1980 lines
39 KiB
Plaintext
1980 lines
39 KiB
Plaintext
# This Source Code Form is subject to the terms of the Mozilla Public License,
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# v. 2.0. If a copy of the MPL was not distributed with this file, You can
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# obtain one at https://mozilla.org/MPL/2.0/.
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# Stage 8 compiler.
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#
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# - Procedure calls in expressions.
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# - Comments between (* and *) are supported. These are still single line
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# comments and they should be on a separate line.
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const
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symbol_builtin_name_int := "Int";
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symbol_builtin_name_word := "Word";
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symbol_builtin_name_pointer := "Pointer";
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symbol_builtin_name_char := "Char";
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symbol_builtin_name_bool := "Bool";
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# Every type info starts with a word describing what type it is.
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#
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# PRIMITIVE_TYPE = 1
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#
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# Primitive types have only type size.
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symbol_builtin_type_int := S(1, 4);
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symbol_builtin_type_word := S(1, 4);
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symbol_builtin_type_pointer := S(1, 4);
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symbol_builtin_type_char := S(1, 1);
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symbol_builtin_type_bool := S(1, 1);
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# Info objects start with a word describing its type.
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#
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# INFO_TYPE = 1
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#
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# Type info has the type it belongs to.
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symbol_type_info_int := S(1, @symbol_builtin_type_int);
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symbol_type_info_word := S(1, @symbol_builtin_type_word);
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symbol_type_info_pointer := S(1, @symbol_builtin_type_pointer);
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symbol_type_info_char := S(1, @symbol_builtin_type_char);
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symbol_type_info_bool := S(1, @symbol_builtin_type_bool);
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var
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source_code: Array;
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compiler_strings: Array;
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symbol_table_global: Array;
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symbol_table_local: Array;
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classification: Array;
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compiler_strings_position: Pointer := @compiler_strings;
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compiler_strings_length: Word := 0;
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source_code_position: Pointer := @source_code;
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# Calculates and returns the string token length between quotes, including the
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# escaping slash characters.
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#
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# Parameters:
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# a0 - String token pointer.
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#
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# Returns the length in a0.
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proc _string_length();
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begin
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# Reset the counter.
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v0 := 0;
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.string_length_loop:
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v88 := v88 + 1;
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lw t0, 88(sp)
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lb t0, (t0)
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li t1, '"'
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beq t0, t1, .string_length_end
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v0 := v0 + 1;
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goto .string_length_loop;
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.string_length_end:
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return v0
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end;
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# Adds a string to the global, read-only string storage.
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#
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# Parameters:
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# a0 - String token.
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#
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# Returns the offset from the beginning of the storage to the new string in a0.
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proc _add_string();
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begin
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v0 := v88 + 1;
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v4 := compiler_strings_length;
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.add_string_loop:
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lw t0, 0(sp)
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lb t1, (t0)
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li t2, '"'
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beq t1, t2, .add_string_end
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la t2, compiler_strings_position
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lw t3, (t2)
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sb t1, (t3)
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addi t3, t3, 1
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sw t3, (t2)
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addi t0, t0, 1
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sw t0, 0(sp)
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li t2, '\\'
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bne t1, t2, .add_string_increment
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goto .add_string_loop;
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.add_string_increment:
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la t2, compiler_strings_length
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lw t4, (t2)
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addi t4, t4, 1
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sw t4, (t2)
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goto .add_string_loop;
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.add_string_end:
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return v4
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end;
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# Reads standard input into a buffer.
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# a0 - Buffer pointer.
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# a1 - Buffer size.
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#
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# Returns the amount of bytes written in a0.
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proc _read_file();
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begin
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mv a2, a1
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mv a1, a0
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# STDIN.
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li a0, 0
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# SYS_READ.
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li a7, 63
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ecall
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end;
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# Writes to the standard output.
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#
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# Parameters:
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# a0 - Buffer.
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# a1 - Buffer length.
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proc _write_s();
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begin
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mv a2, a1
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mv a1, a0
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# STDOUT.
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li a0, 1
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# SYS_WRITE.
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li a7, 64
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ecall
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end;
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# Writes a number to a string buffer.
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#
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# t0 - Local buffer.
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# t1 - Constant 10.
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# t2 - Current character.
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# t3 - Whether the number is negative.
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#
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# Parameters:
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# a0 - Whole number.
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# a1 - Buffer pointer.
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#
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# Sets a0 to the length of the written number.
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proc _print_i();
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begin
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li t1, 10
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addi t0, s0, -9
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li t3, 0
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bgez a0, .print_i_digit10
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li t3, 1
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neg a0, a0
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.print_i_digit10:
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rem t2, a0, t1
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addi t2, t2, '0'
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sb t2, 0(t0)
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div a0, a0, t1
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addi t0, t0, -1
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bne zero, a0, .print_i_digit10
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beq zero, t3, .print_i_write_call
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addi t2, zero, '-'
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sb t2, 0(t0)
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addi t0, t0, -1
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.print_i_write_call:
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mv a0, a1
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addi a1, t0, 1
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sub a2, s0, t0
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addi a2, a2, -9
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sw a2, 0(sp)
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_memcpy();
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return v0
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end;
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# Writes a number to the standard output.
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#
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# Parameters:
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# a0 - Whole number.
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proc _write_i();
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begin
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_print_i(v88, @v0);
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mv a1, a0
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addi a0, sp, 0
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_write_s();
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end;
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# Writes a character from a0 into the standard output.
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proc _write_c();
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begin
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_write_s(@v88, 1);
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end;
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# Write null terminated string.
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#
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# Parameters:
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# a0 - String.
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proc _write_z();
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begin
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.write_z_loop:
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# Check for 0 character.
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lw a0, 88(sp)
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lb a0, (a0)
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beqz a0, .write_z_end
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# Print a character.
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_write_c();
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# Advance the input string by one byte.
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v88 := v88 + 1;
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goto .write_z_loop;
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.write_z_end:
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end;
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# Detects if a0 is an uppercase character. Sets a0 to 1 if so, otherwise to 0.
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proc _is_upper();
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begin
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v0 := v88 >= 'A';
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v4 := v88 <= 'Z';
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return v0 & v4
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end;
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# Detects if a0 is an lowercase character. Sets a0 to 1 if so, otherwise to 0.
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proc _is_lower();
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begin
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v0 := v88 >= 'a';
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v4 := v88 <= 'z';
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return v0 & v4
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end;
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# Detects if the passed character is a 7-bit alpha character or an underscore.
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#
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# Paramters:
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# a0 - Tested character.
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#
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# Sets a0 to 1 if the character is an alpha character or underscore, sets it to 0 otherwise.
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proc _is_alpha();
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begin
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sw a0, 0(sp)
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_is_upper();
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sw a0, 4(sp)
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_is_lower(v0);
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lw t0, 0(sp)
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xori t1, t0, '_'
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seqz t1, t1
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lw t0, 4(sp)
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or a0, a0, t0
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or a0, a0, t1
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end;
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# Detects whether the passed character is a digit
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# (a value between 0 and 9).
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#
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# Parameters:
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# a0 - Exemined value.
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#
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# Sets a0 to 1 if it is a digit, to 0 otherwise.
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proc _is_digit();
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begin
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v0 := v88 >= '0';
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v4 := v88 <= '9';
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return v0 & v4
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end;
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proc _is_alnum();
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begin
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sw a0, 4(sp)
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_is_alpha();
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sw a0, 0(sp)
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_is_digit(v4);
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lw a1, 0(sp)
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or a0, a0, a1
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end;
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# Reads the next token.
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#
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# Returns token length in a0.
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proc _read_token();
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begin
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# Current token position.
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v0 := source_code_position;
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# Token length.
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v4 := 0;
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.read_token_loop:
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lw t0, 0(sp)
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# Current character.
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lb t0, (t0)
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# First we try to read a derictive.
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# A derictive can contain a dot and characters.
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li t1, '.'
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beq t0, t1, .read_token_next
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lw a0, 0(sp)
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lb a0, (a0)
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_is_alnum();
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bnez a0, .read_token_next
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goto .read_token_end;
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.read_token_next:
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# Advance the source code position and token length.
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v4 := v4 + 1;
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v0 := v0 + 1;
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goto .read_token_loop;
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.read_token_end:
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return v4
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end;
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# a0 - First pointer.
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# a1 - Second pointer.
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# a2 - The length to compare.
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#
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# Returns 0 in a0 if memory regions are equal.
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proc _memcmp();
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begin
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mv t0, a0
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li a0, 0
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.memcmp_loop:
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beqz a2, .memcmp_end
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lbu t1, (t0)
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lbu t2, (a1)
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sub a0, t1, t2
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bnez a0, .memcmp_end
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addi t0, t0, 1
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addi a1, a1, 1
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addi a2, a2, -1
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goto .memcmp_loop;
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.memcmp_end:
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end;
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# Copies memory.
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#
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# Parameters:
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# a0 - Destination.
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# a1 - Source.
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# a2 - Size.
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#
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# Preserves a0.
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proc _memcpy();
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begin
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mv t0, a0
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.memcpy_loop:
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beqz a2, .memcpy_end
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lbu t1, (a1)
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sb t1, (a0)
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addi a0, a0, 1
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addi a1, a1, 1
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addi a2, a2, -1
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goto .memcpy_loop
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.memcpy_end:
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mv a0, t0
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end;
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# Advances the token stream by a0 bytes.
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proc _advance_token();
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begin
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la t0, source_code_position
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lw t1, (t0)
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add t1, t1, a0
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sw t1, (t0)
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end;
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# Prints the current token.
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#
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# Parameters:
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# a0 - Token length.
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#
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# Returns a0 unchanged.
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proc _write_token();
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begin
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_write_s(source_code_position, v88);
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return v88
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end;
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# Prints and skips a line.
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proc _compile_line();
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begin
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.compile_line_loop:
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la a0, source_code_position
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lw a1, (a0)
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lb t0, (a1)
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li t1, '\n'
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beq t0, t1, .compile_line_end
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# Print a character.
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lw a0, (a1)
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_write_c();
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# Advance the input string by one byte.
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_advance_token(1);
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goto .compile_line_loop;
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.compile_line_end:
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_write_c('\n');
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_advance_token(1);
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end;
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proc _compile_integer_literal();
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begin
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_write_z("\tli t0, \0");
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_read_token();
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_write_token();
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_advance_token();
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_write_c('\n');
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end;
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proc _compile_character_literal();
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begin
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_write_z("\tli t0, \0");
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_write_c('\'');
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_advance_token(1);
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la t0, source_code_position
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lw t0, (t0)
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lb a0, (t0)
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li t1, '\\'
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bne a0, t1, .compile_character_literal_end
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_write_c('\\');
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_advance_token(1);
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.compile_character_literal_end:
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la t0, source_code_position
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lw t0, (t0)
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lb a0, (t0)
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_write_c();
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_write_c('\'');
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_write_c('\n');
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_advance_token(2);
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end;
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proc _compile_variable_expression();
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begin
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_compile_designator();
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_write_z("\tlw t0, (t0)\n\0");
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end;
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proc _compile_address_expression();
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begin
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# Skip the "@" sign.
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_advance_token(1);
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_compile_designator();
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end;
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proc _compile_negate_expression();
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begin
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# Skip the "-" sign.
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_advance_token(1);
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_compile_term();
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_write_z("\tneg t0, t0\n\0");
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end;
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proc _compile_not_expression();
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begin
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# Skip the "~" sign.
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_advance_token(1);
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_compile_term();
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_write_z("\tnot t0, t0\n\0");
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end;
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proc _compile_string_literal();
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begin
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_string_length(source_code_position);
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sw a0, 0(sp)
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_add_string(source_code_position);
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sw a0, 4(sp)
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_advance_token(v0 + 2);
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_write_z("\tla t0, strings\n\0");
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_write_z("\tli t1, \0");
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_write_i(v4);
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_write_c('\n');
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_write_z("\tadd t0, t0, t1\n\0");
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end;
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proc _compile_term();
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begin
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la t0, source_code_position
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lw t0, (t0)
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lb a0, (t0)
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sw a0, 0(sp)
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li t1, '\''
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beq a0, t1, .compile_term_character_literal
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li t1, '@'
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beq a0, t1, .compile_term_address
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li t1, '-'
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beq a0, t1, .compile_term_negation
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li t1, '~'
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beq a0, t1, .compile_term_not
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li t1, '"'
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beq a0, t1, .compile_term_string_literal
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li t1, '_'
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beq a0, t1, .compile_term_call
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_is_digit(v0);
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bnez a0, .compile_term_integer_literal
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goto .compile_term_variable;
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.compile_term_character_literal:
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_compile_character_literal();
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goto .compile_term_end;
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.compile_term_integer_literal:
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_compile_integer_literal();
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goto .compile_term_end;
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.compile_term_address:
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_compile_address_expression();
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goto .compile_term_end;
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.compile_term_negation:
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_compile_negate_expression();
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goto .compile_term_end;
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.compile_term_not:
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_compile_not_expression();
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goto .compile_term_end;
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.compile_term_string_literal:
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_compile_string_literal();
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goto .compile_term_end;
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.compile_term_call:
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_compile_call();
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_write_z("\nmv t0, a0\n\0");
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goto .compile_term_end;
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.compile_term_variable:
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_compile_variable_expression();
|
|
goto .compile_term_end;
|
|
|
|
.compile_term_end:
|
|
end;
|
|
|
|
proc _compile_binary_rhs();
|
|
begin
|
|
# Skip the whitespace after the binary operator.
|
|
_advance_token(1);
|
|
_compile_term();
|
|
|
|
# Load the left expression from the stack;
|
|
_write_z("\tlw t1, 24(sp)\n\0");
|
|
end;
|
|
|
|
proc _compile_expression();
|
|
begin
|
|
_compile_term();
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb a0, (t0)
|
|
|
|
li t1, ' '
|
|
bne a0, t1, .compile_expression_end
|
|
|
|
# It is a binary expression.
|
|
|
|
# Save the value of the left expression on the stack.
|
|
_write_z("sw t0, 24(sp)\n\0");
|
|
|
|
# Skip surrounding whitespace in front of the operator.
|
|
_advance_token(1);
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, '+'
|
|
beq t0, t1, .compile_expression_add
|
|
|
|
li t1, '*'
|
|
beq t0, t1, .compile_expression_mul
|
|
|
|
li t1, '&'
|
|
beq t0, t1, .compile_expression_and
|
|
|
|
li t1, 'o'
|
|
beq t0, t1, .compile_expression_or
|
|
|
|
li t1, 'x'
|
|
beq t0, t1, .compile_expression_xor
|
|
|
|
li t1, '='
|
|
beq t0, t1, .compile_expression_equals
|
|
|
|
li t1, '<'
|
|
beq t0, t1, .compile_expression_less
|
|
|
|
li t1, '>'
|
|
beq t0, t1, .compile_expression_greater
|
|
|
|
# Unknown binary operator.
|
|
unimp
|
|
|
|
.compile_expression_add:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("add t0, t0, t1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_mul:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("\tmul t0, t0, t1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_and:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("\tand t0, t0, t1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_or:
|
|
_advance_token(2);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("or t0, t0, t1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_xor:
|
|
_advance_token(3);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("xor t0, t0, t1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_equals:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("xor t0, t0, t1\nseqz t0, t0\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_less:
|
|
_advance_token(1);
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, '>'
|
|
beq t0, t1, .compile_expression_not_equal
|
|
|
|
li t1, '='
|
|
beq t0, t1, .compile_expression_less_equal
|
|
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("slt t0, t0, t1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_not_equal:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("\txor t0, t0, t1\nsnez t0, t0\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_less_equal:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("\tslt t0, t0, t1\nxori t0, t0, 1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_greater:
|
|
_advance_token(1);
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, '='
|
|
beq t0, t1, .compile_expression_greater_equal
|
|
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("\tslt t0, t1, t0\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_greater_equal:
|
|
_advance_token(1);
|
|
_compile_binary_rhs();
|
|
|
|
# Execute the operation.
|
|
_write_z("\tslt t0, t1, t0\nxori t0, t0, 1\n\0");
|
|
|
|
goto .compile_expression_end;
|
|
|
|
.compile_expression_end:
|
|
end;
|
|
|
|
proc _compile_call();
|
|
begin
|
|
# Stack variables:
|
|
# v0 - Procedure name length.
|
|
# v4 - Procedure name pointer.
|
|
# v8 - Argument count.
|
|
|
|
_read_token();
|
|
sw a0, 0(sp)
|
|
v4 := source_code_position;
|
|
v8 := 0;
|
|
|
|
# Skip the identifier and left paren.
|
|
_advance_token(v0 + 1);
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, ')'
|
|
beq t0, t1, .compile_call_finalize
|
|
|
|
.compile_call_loop:
|
|
_compile_expression();
|
|
|
|
# Save the argument on the stack.
|
|
_write_z("\tsw t0, \0");
|
|
|
|
# Calculate the stack offset: 116 - (4 * argument_counter)
|
|
v12 := v8 * 4;
|
|
v12 := 116 + -v12;
|
|
_write_i(v12);
|
|
|
|
_write_z("(sp)\n\0");
|
|
|
|
# Add one to the argument counter.
|
|
v8 := v8 + 1;
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, ','
|
|
bne t0, t1, .compile_call_finalize
|
|
|
|
_advance_token(2);
|
|
goto .compile_call_loop;
|
|
|
|
.compile_call_finalize:
|
|
# Load the argument from the stack.
|
|
|
|
lw t0, 8(sp)
|
|
beqz t0, .compile_call_end
|
|
|
|
# Decrement the argument counter.
|
|
v8 := v8 + -1;
|
|
|
|
_write_z("\tlw a\0");
|
|
_write_i(v8);
|
|
|
|
_write_z(", \0");
|
|
|
|
# Calculate the stack offset: 116 - (4 * argument_counter)
|
|
v12 := v8 * 4;
|
|
v12 := 116 + -v12;
|
|
_write_i(v12);
|
|
|
|
_write_z("(sp)\n\0");
|
|
|
|
goto .compile_call_finalize;
|
|
|
|
.compile_call_end:
|
|
_write_z("\tcall \0");
|
|
_write_s(v4, v0);
|
|
|
|
# Skip the right paren.
|
|
_advance_token(1);
|
|
end;
|
|
|
|
proc _compile_goto();
|
|
begin
|
|
_advance_token(5);
|
|
|
|
_read_token();
|
|
sw a0, 0(sp)
|
|
|
|
_write_z("\tj \0");
|
|
|
|
_write_token(v0);
|
|
_advance_token();
|
|
end;
|
|
|
|
proc _compile_local_designator();
|
|
begin
|
|
# Skip "v" in the local variable name.
|
|
_advance_token(1);
|
|
_write_z("\t addi t0, sp, \0");
|
|
|
|
# Read local variable stack offset and save it.
|
|
_read_token();
|
|
_write_token();
|
|
_advance_token();
|
|
_write_c('\n');
|
|
end;
|
|
|
|
proc _compile_global_designator();
|
|
begin
|
|
_write_z("\tla t0, \0");
|
|
|
|
_read_token();
|
|
_write_token();
|
|
_advance_token();
|
|
|
|
_write_c('\n');
|
|
end;
|
|
|
|
proc _compile_designator();
|
|
begin
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb a0, (t0)
|
|
|
|
li t1, 'v'
|
|
beq a0, t1, .compile_designator_local
|
|
|
|
goto .compile_designator_global;
|
|
|
|
.compile_designator_local:
|
|
_compile_local_designator();
|
|
goto .compile_designator_end;
|
|
|
|
.compile_designator_global:
|
|
_compile_global_designator();
|
|
goto .compile_designator_end;
|
|
|
|
.compile_designator_end:
|
|
end;
|
|
|
|
proc _compile_assignment();
|
|
begin
|
|
_compile_designator();
|
|
|
|
# Save the assignee address on the stack.
|
|
_write_z("\tsw t0, 20(sp)\n\0");
|
|
|
|
# Skip the assignment sign (:=) with surrounding whitespaces.
|
|
_advance_token(4);
|
|
|
|
# Compile the assignment.
|
|
_compile_expression();
|
|
|
|
_write_z("\tlw t1, 20(sp)\nsw t0, (t1)\n\0");
|
|
end;
|
|
|
|
proc _compile_return_statement();
|
|
begin
|
|
# Skip "return" keyword and whitespace after it.
|
|
_advance_token(7);
|
|
_compile_expression();
|
|
|
|
_write_z("mv a0, t0\n\0");
|
|
end;
|
|
|
|
proc _compile_statement();
|
|
begin
|
|
# This is a call if the statement starts with an underscore.
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
# First character after alignment tab.
|
|
addi t0, t0, 1
|
|
lb t0, (t0)
|
|
|
|
li t1, '_'
|
|
beq t0, t1, .compile_statement_call
|
|
|
|
li t1, 'g'
|
|
beq t0, t1, .compile_statement_goto
|
|
|
|
li t1, 'v'
|
|
beq t0, t1, .compile_statement_assignment
|
|
|
|
# keyword_ret contains "\tret", so it's 4 bytes long.
|
|
_memcmp(source_code_position, "\treturn", 7);
|
|
beqz a0, .compile_statement_return
|
|
|
|
_compile_line();
|
|
goto .compile_statement_end;
|
|
|
|
.compile_statement_call:
|
|
_advance_token(1);
|
|
_compile_call();
|
|
|
|
goto .compile_statement_semicolon;
|
|
|
|
.compile_statement_goto:
|
|
_advance_token(1);
|
|
_compile_goto();
|
|
|
|
goto .compile_statement_semicolon;
|
|
|
|
.compile_statement_assignment:
|
|
_advance_token(1);
|
|
_compile_assignment();
|
|
|
|
goto .compile_statement_semicolon;
|
|
|
|
.compile_statement_return:
|
|
_advance_token(1);
|
|
_compile_return_statement();
|
|
_write_c('\n');
|
|
|
|
goto .compile_statement_end;
|
|
|
|
.compile_statement_semicolon:
|
|
_advance_token(2);
|
|
_write_c('\n');
|
|
|
|
.compile_statement_end:
|
|
end;
|
|
|
|
proc _compile_procedure_body();
|
|
begin
|
|
.compile_procedure_body_loop:
|
|
_skip_empty_lines();
|
|
|
|
# 3 is "end" length.
|
|
_memcmp(source_code_position, "end", 3);
|
|
|
|
beqz a0, .compile_procedure_body_epilogue
|
|
|
|
_compile_statement();
|
|
goto .compile_procedure_body_loop;
|
|
|
|
.compile_procedure_body_epilogue:
|
|
end;
|
|
|
|
# Writes a regster name to the standard output.
|
|
#
|
|
# Parameters:
|
|
# a0 - Register character.
|
|
# a1 - Register number.
|
|
proc _write_register();
|
|
begin
|
|
_write_c(v88);
|
|
v84 := v84 + '0';
|
|
_write_c(v84);
|
|
end;
|
|
|
|
proc _compile_procedure_prologue();
|
|
begin
|
|
_write_z("\taddi sp, sp, -128\n\tsw ra, 124(sp)\n\tsw s0, 120(sp)\n\taddi s0, sp, 128\n\0");
|
|
v0 := 0;
|
|
|
|
.compile_procedure_prologue_loop:
|
|
_write_z("\tsw a\0");
|
|
_write_i(v0);
|
|
_write_z(", \0");
|
|
|
|
# Calculate the stack offset: 88 - (4 * parameter_counter)
|
|
v4 := v0 * 4;
|
|
v4 := 88 + -v4;
|
|
_write_i(v4);
|
|
|
|
_write_z("(sp)\n\0");
|
|
|
|
v0 := v0 + 1;
|
|
lw a0, 0(sp)
|
|
|
|
li t0, 8
|
|
bne a0, t0, .compile_procedure_prologue_loop
|
|
end;
|
|
|
|
proc _compile_procedure();
|
|
begin
|
|
# Skip "proc ".
|
|
_advance_token(5);
|
|
|
|
_read_token();
|
|
# Save the procedure name length.
|
|
sw a0, 0(sp)
|
|
|
|
# Write .type _procedure_name, @function.
|
|
_write_z(".type \0");
|
|
|
|
_write_token(v0);
|
|
_write_z(", @function\n\0");
|
|
|
|
# Write procedure label, _procedure_name:
|
|
_write_token(v0);
|
|
_write_z(":\n\0");
|
|
|
|
# Skip the function name and trailing parens, semicolon, "begin" and newline.
|
|
_advance_token(v0 + 10);
|
|
|
|
_compile_procedure_prologue();
|
|
_compile_procedure_body();
|
|
|
|
# Write the epilogue.
|
|
_write_z("\tlw ra, 124(sp)\n\tlw s0, 120(sp)\n\taddi sp, sp, 128\n\tret\n\0");
|
|
|
|
# Skip the "end" keyword, semicolon and newline.
|
|
_advance_token(5);
|
|
end;
|
|
|
|
proc _skip_newlines();
|
|
begin
|
|
# Skip newlines.
|
|
la t0, source_code_position
|
|
lw t1, (t0)
|
|
|
|
.skip_newlines_loop:
|
|
lb t2, (t1)
|
|
li t3, '\n'
|
|
bne t2, t3, .skip_newlines_end
|
|
beqz t2, .skip_newlines_end
|
|
|
|
addi t1, t1, 1
|
|
sw t1, (t0)
|
|
|
|
goto .skip_newlines_loop;
|
|
|
|
.skip_newlines_end:
|
|
end;
|
|
|
|
# Prints and skips a line.
|
|
proc _skip_comment();
|
|
begin
|
|
la t0, source_code_position
|
|
lw t1, (t0)
|
|
|
|
.skip_comment_loop:
|
|
# Check for newline character.
|
|
lb t2, (t1)
|
|
li t3, '\n'
|
|
beq t2, t3, .skip_comment_end
|
|
|
|
# Advance the input string by one byte.
|
|
addi t1, t1, 1
|
|
sw t1, (t0)
|
|
|
|
goto .skip_comment_loop;
|
|
|
|
.skip_comment_end:
|
|
# Skip the newline.
|
|
addi t1, t1, 1
|
|
sw t1, (t0)
|
|
end;
|
|
|
|
# Skip newlines and comments.
|
|
proc _skip_empty_lines();
|
|
begin
|
|
.skip_empty_lines_rerun:
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
sw t0, 0(sp)
|
|
|
|
.skip_empty_lines_loop:
|
|
lw t2, 0(sp)
|
|
lb t0, (t2)
|
|
|
|
li t1, '#'
|
|
beq t0, t1, .skip_empty_lines_comment
|
|
|
|
li t1, '\n'
|
|
beq t0, t1, .skip_empty_lines_newline
|
|
|
|
li t1, '\t'
|
|
beq t0, t1, .skip_empty_lines_tab
|
|
|
|
li t1, '('
|
|
bne t0, t1, .skip_empty_lines_end
|
|
addi t2, t2, 1
|
|
lb t0, (t2)
|
|
li t1, '*'
|
|
beq t0, t1, .skip_empty_lines_comment
|
|
|
|
goto .skip_empty_lines_end;
|
|
|
|
.skip_empty_lines_comment:
|
|
la t0, source_code_position
|
|
lw t1, 0(sp)
|
|
sw t1, (t0)
|
|
_skip_comment();
|
|
goto .skip_empty_lines_rerun;
|
|
|
|
.skip_empty_lines_newline:
|
|
la t0, source_code_position
|
|
lw t1, 0(sp)
|
|
addi t1, t1, 1
|
|
sw t1, (t0)
|
|
goto .skip_empty_lines_rerun;
|
|
|
|
.skip_empty_lines_tab:
|
|
v0 := v0 + 1;
|
|
goto .skip_empty_lines_loop
|
|
|
|
.skip_empty_lines_end:
|
|
end;
|
|
|
|
proc _compile_global_initializer();
|
|
begin
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, '"'
|
|
beq t0, t1, .compile_global_initializer_string
|
|
|
|
li t1, 'S'
|
|
beq t0, t1, .compile_global_initializer_record
|
|
|
|
li t1, '@'
|
|
beq t0, t1, .compile_global_initializer_pointer
|
|
|
|
la a0, source_code_position
|
|
lw a0, (a0)
|
|
lb a0, (a0)
|
|
_is_digit();
|
|
bnez a0, .compile_global_initializer_number
|
|
|
|
unimp
|
|
|
|
.compile_global_initializer_pointer:
|
|
# Skip @.
|
|
_advance_token(1);
|
|
_write_z("\n\t.word \0");
|
|
_read_token();
|
|
_write_token();
|
|
_advance_token();
|
|
|
|
goto .compile_global_initializer_end;
|
|
|
|
.compile_global_initializer_number:
|
|
_write_z("\n\t.word \0");
|
|
_read_token();
|
|
_write_token();
|
|
_advance_token(1);
|
|
|
|
goto .compile_global_initializer_end;
|
|
|
|
.compile_global_initializer_record:
|
|
# Skip "S(".
|
|
_advance_token(2);
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
li t1, ')'
|
|
beq t0, t1, .compile_global_initializer_closing
|
|
|
|
.compile_global_initializer_loop:
|
|
_compile_global_initializer();
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
li t1, ')'
|
|
beq t0, t1, .compile_global_initializer_closing
|
|
|
|
# Skip comma and whitespace after it.
|
|
_advance_token(2);
|
|
|
|
goto .compile_global_initializer_loop;
|
|
|
|
.compile_global_initializer_closing:
|
|
# Skip ")"
|
|
_advance_token(1);
|
|
|
|
goto .compile_global_initializer_end;
|
|
|
|
.compile_global_initializer_string:
|
|
_write_z("\n\t.word strings + \0");
|
|
_string_length(source_code_position);
|
|
sw a0, 4(sp)
|
|
|
|
_add_string(source_code_position);
|
|
_write_i();
|
|
|
|
# Skip the quoted string.
|
|
_advance_token(v4 + 2);
|
|
|
|
goto .compile_global_initializer_end;
|
|
|
|
.compile_global_initializer_end:
|
|
end;
|
|
|
|
proc _compile_constant_declaration();
|
|
begin
|
|
_read_token();
|
|
sw a0, 0(sp)
|
|
|
|
_write_z(".type \0");
|
|
_write_token(v0);
|
|
_write_z(", @object\n\0");
|
|
|
|
_write_token(v0);
|
|
_write_c(':');
|
|
|
|
# Skip the constant name with assignment sign and surrounding whitespaces.
|
|
_advance_token(v0 + 4);
|
|
_compile_global_initializer();
|
|
# Skip semicolon and newline.
|
|
_advance_token(2);
|
|
_write_c('\n');
|
|
end;
|
|
|
|
proc _compile_const_part();
|
|
begin
|
|
_skip_empty_lines();
|
|
|
|
_memcmp(source_code_position, "const\0", 5);
|
|
bnez a0, .compile_const_part_end
|
|
|
|
# Skip "const" with the newline after it.
|
|
_advance_token(6);
|
|
_write_z(".section .rodata # Compiled from const section.\n\n\0");
|
|
|
|
.compile_const_part_loop:
|
|
_skip_empty_lines();
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
# If the character at the line beginning is not indentation,
|
|
# it is probably the next code section.
|
|
li t1, '\t'
|
|
bne t0, t1, .compile_const_part_end
|
|
|
|
_advance_token(1);
|
|
|
|
_compile_constant_declaration();
|
|
goto .compile_const_part_loop;
|
|
|
|
.compile_const_part_end:
|
|
end;
|
|
|
|
proc _compile_variable_declaration();
|
|
begin
|
|
_read_token();
|
|
sw a0, 0(sp)
|
|
|
|
_write_z(".type \0");
|
|
_write_token(v0);
|
|
_write_z(", @object\n\0");
|
|
|
|
_write_token(v0);
|
|
_write_c(':');
|
|
|
|
# Skip the variable name and colon with space before the type.
|
|
_advance_token(v0 + 2);
|
|
|
|
# Skip the type name.
|
|
_read_token();
|
|
_advance_token();
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
li t1, ' '
|
|
beq t0, t1, .compile_variable_declaration_initializer
|
|
|
|
# Else we assume this is a zeroed 81920 bytes big array.
|
|
_write_z(" .zero 81920\0");
|
|
goto .compile_variable_declaration_finalize;
|
|
|
|
.compile_variable_declaration_initializer:
|
|
# Skip the assignment sign with surrounding whitespaces.
|
|
_advance_token(4);
|
|
_compile_global_initializer();
|
|
goto .compile_variable_declaration_finalize;
|
|
|
|
.compile_variable_declaration_finalize:
|
|
# Skip semicolon and newline.
|
|
_advance_token(2);
|
|
_write_c('\n');
|
|
end;
|
|
|
|
proc _compile_var_part();
|
|
begin
|
|
_memcmp(source_code_position, "var\0", 3);
|
|
bnez a0, .compile_var_part_end
|
|
|
|
# Skip "var" and newline.
|
|
_advance_token(4);
|
|
_write_z(".section .data\n\0");
|
|
|
|
.compile_var_part_loop:
|
|
_skip_empty_lines();
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
|
|
li t1, '\t'
|
|
beq t0, t1, .compile_var_part_declaration
|
|
|
|
goto .compile_var_part_end;
|
|
|
|
.compile_var_part_declaration:
|
|
_advance_token(1);
|
|
_compile_variable_declaration();
|
|
goto .compile_var_part_loop;
|
|
|
|
.compile_var_part_end:
|
|
end;
|
|
|
|
# Process the source code and print the generated code.
|
|
proc _compile_module();
|
|
begin
|
|
_compile_const_part();
|
|
_skip_empty_lines();
|
|
_compile_var_part();
|
|
|
|
_write_z(".section .text\n\0");
|
|
.compile_module_loop:
|
|
_skip_empty_lines();
|
|
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
lb t0, (t0)
|
|
beqz t0, .compile_module_end
|
|
|
|
# 5 is "proc " length. Space is needed to distinguish from "procedure".
|
|
_memcmp(source_code_position, "proc ", 5);
|
|
beqz a0, .compile_module_procedure
|
|
|
|
# Not a known token, exit.
|
|
goto .compile_module_end;
|
|
|
|
.compile_module_procedure:
|
|
_compile_procedure();
|
|
|
|
goto .compile_module_loop;
|
|
|
|
.compile_module_end:
|
|
end;
|
|
|
|
proc _compile();
|
|
begin
|
|
_write_z(".globl _start\n\n\0");
|
|
_compile_module();
|
|
|
|
_write_z(".section .rodata\n.type strings, @object\nstrings: .ascii \0");
|
|
_write_c('"');
|
|
|
|
la t0, compiler_strings
|
|
sw t0, 0(sp)
|
|
|
|
.compile_loop:
|
|
lw t0, 0(sp)
|
|
la t1, compiler_strings_position
|
|
lw t1, (t1)
|
|
bge t0, t1, .compile_end
|
|
|
|
lb a0, (t0)
|
|
|
|
addi t0, t0, 1
|
|
sw t0, 0(sp)
|
|
|
|
_write_c();
|
|
|
|
j .compile_loop
|
|
|
|
.compile_end:
|
|
_write_c('"');
|
|
_write_c('\n');
|
|
end;
|
|
|
|
# Terminates the program. a0 contains the return code.
|
|
#
|
|
# Parameters:
|
|
# a0 - Status code.
|
|
proc _exit();
|
|
begin
|
|
li a7, 93 # SYS_EXIT
|
|
ecall
|
|
end;
|
|
|
|
# Inserts a symbol into the table.
|
|
#
|
|
# Parameters:
|
|
# a0 - Symbol pointer.
|
|
# a1 - Symbol name length.
|
|
# a2 - Symbol name pointer.
|
|
# a3 - Symbol table.
|
|
proc _symbol_table_enter();
|
|
begin
|
|
# The first word in the symbol table is its length, get it.
|
|
lw a0, 76(sp)
|
|
lw a0, (a0)
|
|
sw a0, 0(sp)
|
|
|
|
# Calculate the offset for the new symbol.
|
|
v4 := v0 * 4;
|
|
v4 := v4 + 4;
|
|
v4 := v76 + 4;
|
|
|
|
_memcpy(v4, @v80, 12);
|
|
|
|
# Increment the symbol table length.
|
|
v0 := v0 + 1;
|
|
lw t0, 0(sp)
|
|
lw t1, 76(sp)
|
|
sw t0, (t1)
|
|
end;
|
|
|
|
proc _symbol_table_build();
|
|
begin
|
|
_symbol_table_enter(@symbol_type_info_int, 3, symbol_builtin_name_int, @symbol_table_global);
|
|
_symbol_table_enter(@symbol_type_info_word, 4, symbol_builtin_name_word, @symbol_table_global);
|
|
_symbol_table_enter(@symbol_type_info_pointer, 7, symbol_builtin_name_pointer, @symbol_table_global);
|
|
_symbol_table_enter(@symbol_type_info_char, 4, symbol_builtin_name_char, @symbol_table_global);
|
|
_symbol_table_enter(@symbol_type_info_bool, 4, symbol_builtin_name_bool, @symbol_table_global);
|
|
end;
|
|
|
|
#
|
|
# Classification table assigns each possible character to a group (class). All
|
|
# characters of the same group a handled equivalently.
|
|
#
|
|
# Classification:
|
|
#
|
|
# TransitionClass = (
|
|
# transitionClassInvalid = 1,
|
|
# transitionClassDigit = 2,
|
|
# transitionClassAlpha = 3,
|
|
# transitionClassSpace = 4,
|
|
# transitionClassColon = 5,
|
|
# transitionClassEquals = 6,
|
|
# transitionClassLeftParen = 7,
|
|
# transitionClassRightParen = 8,
|
|
# transitionClassAsterisk = 9,
|
|
# transitionClassUnderscore = 10,
|
|
# transitionClassSingle = 11,
|
|
# transitionClassHex = 12,
|
|
# transitionClassZero = 13,
|
|
# transitionClassX = 14,
|
|
# transitionClassEof = 15,
|
|
# transitionClassDot = 16,
|
|
# transitionClassMinus = 17,
|
|
# transitionClassSingleQuote = 18,
|
|
# transitionClassDoubleQuote = 19,
|
|
# transitionClassGreater = 20,
|
|
# transitionClassLess = 21,
|
|
# transitionClassOther = 22
|
|
# );
|
|
# TransitionState = (
|
|
# transitionStateStart = 1,
|
|
# transitionStateColon = 2,
|
|
# transitionStateIdentifier = 3,
|
|
# transitionStateDecimal = 4,
|
|
# transitionStateGreater = 5,
|
|
# transitionStateMinus = 6,
|
|
# transitionStateLeftParen = 7,
|
|
# transitionStateLess = 8,
|
|
# transitionStateDot = 9,
|
|
# transitionStateComment = 10,
|
|
# transitionStateClosingComment = 11,
|
|
# transitionStateCharacter = 12,
|
|
# transitionStateString = 13,
|
|
# transitionStateLeadingZero = 14,
|
|
# transitionStateDecimalSuffix = 15,
|
|
# transitionStateEnd = 16
|
|
# );
|
|
# Transition = record
|
|
# action: TransitionAction;
|
|
# next_state: TransitionState
|
|
# end;
|
|
# TransitionAction = (
|
|
# none = 1,
|
|
# accumulate = 2,
|
|
# skip = 3,
|
|
# single = 4,
|
|
# eof = 5,
|
|
# finalize = 6,
|
|
# composite = 7,
|
|
# key_id = 8,
|
|
# integer = 9,
|
|
# delimited = 10
|
|
# );
|
|
|
|
# Assigns some value to at array index.
|
|
#
|
|
# Parameters:
|
|
# a0 - Array pointer.
|
|
# a1 - Index (word offset into the array).
|
|
# a2 - Data to assign.
|
|
proc _assign_at();
|
|
begin
|
|
v0 := v84 + -1;
|
|
v0 := v0 * 4;
|
|
v0 := v88 + v0;
|
|
|
|
lw t0, 0(sp)
|
|
lw t1, 80(sp)
|
|
sw t1, (t0)
|
|
end;
|
|
|
|
proc _initialize_classification();
|
|
begin
|
|
_assign_at(@classification, 1, 15);
|
|
_assign_at(@classification, 2, 1);
|
|
_assign_at(@classification, 3, 1);
|
|
_assign_at(@classification, 4, 1);
|
|
_assign_at(@classification, 5, 1);
|
|
_assign_at(@classification, 6, 1);
|
|
_assign_at(@classification, 7, 1);
|
|
_assign_at(@classification, 8, 1);
|
|
_assign_at(@classification, 9, 1);
|
|
_assign_at(@classification, 10, 4);
|
|
_assign_at(@classification, 11, 4);
|
|
_assign_at(@classification, 12, 1);
|
|
_assign_at(@classification, 13, 1);
|
|
_assign_at(@classification, 14, 4);
|
|
_assign_at(@classification, 15, 1);
|
|
_assign_at(@classification, 16, 1);
|
|
_assign_at(@classification, 17, 1);
|
|
_assign_at(@classification, 18, 1);
|
|
_assign_at(@classification, 19, 1);
|
|
_assign_at(@classification, 20, 1);
|
|
_assign_at(@classification, 21, 1);
|
|
_assign_at(@classification, 22, 1);
|
|
_assign_at(@classification, 23, 1);
|
|
_assign_at(@classification, 24, 1);
|
|
_assign_at(@classification, 25, 1);
|
|
_assign_at(@classification, 26, 1);
|
|
_assign_at(@classification, 27, 1);
|
|
_assign_at(@classification, 28, 1);
|
|
_assign_at(@classification, 29, 1);
|
|
_assign_at(@classification, 30, 1);
|
|
_assign_at(@classification, 31, 1);
|
|
_assign_at(@classification, 32, 1);
|
|
_assign_at(@classification, 33, 4);
|
|
_assign_at(@classification, 34, 11);
|
|
_assign_at(@classification, 35, 19);
|
|
_assign_at(@classification, 36, 22);
|
|
_assign_at(@classification, 37, 22);
|
|
_assign_at(@classification, 38, 11);
|
|
_assign_at(@classification, 39, 11);
|
|
_assign_at(@classification, 40, 18);
|
|
_assign_at(@classification, 41, 7);
|
|
_assign_at(@classification, 42, 8);
|
|
_assign_at(@classification, 43, 9);
|
|
_assign_at(@classification, 44, 11);
|
|
_assign_at(@classification, 45, 11);
|
|
_assign_at(@classification, 46, 17);
|
|
_assign_at(@classification, 47, 16);
|
|
_assign_at(@classification, 48, 11);
|
|
_assign_at(@classification, 49, 13);
|
|
_assign_at(@classification, 50, 2);
|
|
_assign_at(@classification, 51, 2);
|
|
_assign_at(@classification, 52, 2);
|
|
_assign_at(@classification, 53, 2);
|
|
_assign_at(@classification, 54, 2);
|
|
_assign_at(@classification, 55, 2);
|
|
_assign_at(@classification, 56, 2);
|
|
_assign_at(@classification, 57, 2);
|
|
_assign_at(@classification, 58, 2);
|
|
_assign_at(@classification, 59, 5);
|
|
_assign_at(@classification, 60, 11);
|
|
_assign_at(@classification, 61, 21);
|
|
_assign_at(@classification, 62, 6);
|
|
_assign_at(@classification, 63, 20);
|
|
_assign_at(@classification, 64, 22);
|
|
_assign_at(@classification, 65, 11);
|
|
_assign_at(@classification, 66, 3);
|
|
_assign_at(@classification, 67, 3);
|
|
_assign_at(@classification, 68, 3);
|
|
_assign_at(@classification, 69, 3);
|
|
_assign_at(@classification, 70, 3);
|
|
_assign_at(@classification, 71, 3);
|
|
_assign_at(@classification, 72, 3);
|
|
_assign_at(@classification, 73, 3);
|
|
_assign_at(@classification, 74, 3);
|
|
_assign_at(@classification, 75, 3);
|
|
_assign_at(@classification, 76, 3);
|
|
_assign_at(@classification, 77, 3);
|
|
_assign_at(@classification, 78, 3);
|
|
_assign_at(@classification, 79, 3);
|
|
_assign_at(@classification, 80, 3);
|
|
_assign_at(@classification, 81, 3);
|
|
_assign_at(@classification, 82, 3);
|
|
_assign_at(@classification, 83, 3);
|
|
_assign_at(@classification, 84, 3);
|
|
_assign_at(@classification, 85, 3);
|
|
_assign_at(@classification, 86, 3);
|
|
_assign_at(@classification, 87, 3);
|
|
_assign_at(@classification, 88, 3);
|
|
_assign_at(@classification, 89, 3);
|
|
_assign_at(@classification, 90, 3);
|
|
_assign_at(@classification, 91, 3);
|
|
_assign_at(@classification, 92, 11);
|
|
_assign_at(@classification, 93, 22);
|
|
_assign_at(@classification, 94, 11);
|
|
_assign_at(@classification, 95, 11);
|
|
_assign_at(@classification, 96, 10);
|
|
_assign_at(@classification, 97, 22);
|
|
_assign_at(@classification, 98, 12);
|
|
_assign_at(@classification, 99, 12);
|
|
_assign_at(@classification, 100, 12);
|
|
_assign_at(@classification, 101, 12);
|
|
_assign_at(@classification, 102, 12);
|
|
_assign_at(@classification, 103, 12);
|
|
_assign_at(@classification, 104, 3);
|
|
_assign_at(@classification, 105, 3);
|
|
_assign_at(@classification, 106, 3);
|
|
_assign_at(@classification, 107, 3);
|
|
_assign_at(@classification, 108, 3);
|
|
_assign_at(@classification, 109, 3);
|
|
_assign_at(@classification, 110, 3);
|
|
_assign_at(@classification, 111, 3);
|
|
_assign_at(@classification, 112, 3);
|
|
_assign_at(@classification, 113, 3);
|
|
_assign_at(@classification, 114, 3);
|
|
_assign_at(@classification, 115, 3);
|
|
_assign_at(@classification, 116, 3);
|
|
_assign_at(@classification, 117, 3);
|
|
_assign_at(@classification, 118, 3);
|
|
_assign_at(@classification, 119, 3);
|
|
_assign_at(@classification, 120, 3);
|
|
_assign_at(@classification, 121, 14);
|
|
_assign_at(@classification, 122, 3);
|
|
_assign_at(@classification, 123, 3);
|
|
_assign_at(@classification, 124, 22);
|
|
_assign_at(@classification, 125, 11);
|
|
_assign_at(@classification, 126, 22);
|
|
_assign_at(@classification, 127, 11);
|
|
_assign_at(@classification, 128, 1);
|
|
|
|
v0 := 129;
|
|
|
|
# Set the remaining 129 - 256 bytes to transitionClassOther.
|
|
.initialize_classification_loop:
|
|
_assign_at(@classification, v0, 22);
|
|
v0 := v0 + 1;
|
|
|
|
lw t0, 0(sp)
|
|
li t1, 257
|
|
blt t0, t1, .initialize_classification_loop
|
|
end;
|
|
|
|
# Parameters:
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# a0 - Current state (first index into transitions table).
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# a1 - Transition (second index into transitions table)..
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# a2 - Action to assign.
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# a3 - Next state to assign.
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proc _set_transition();
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begin
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# Transitions start at offset in classification array. Save the transitions start in v0.
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la t0, classification
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addi t0, t0, 256
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sw t0, 0(sp)
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# Each state is 8 bytes long (2 words: action and next state).
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# There are 16 transition classes, so a transition 8 * 16 = 128 bytes long.
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v4 := v88 + -1;
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v4 := v4 * 128;
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v8 := v84 + -1;
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v8 := v8 * 8;
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v12 := v0 + v4;
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v12 := v12 + v8;
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lw t0, 12(sp)
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lw t1, 80(sp)
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lw t2, 76(sp)
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sw t1, (t0)
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addi t0, t0, 4
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sw t2, (t0)
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end;
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# Parameters:
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# a0 - Current state (Transition state enumeration).
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# a1 - Default action (Callback).
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# a2 - Next state (Transition state enumeration).
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proc _set_default_transition();
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begin
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_set_transition(v88, 1, v84, v80);
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_set_transition(v88, 2, v84, v80);
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_set_transition(v88, 3, v84, v80);
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_set_transition(v88, 4, v84, v80);
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_set_transition(v88, 5, v84, v80);
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_set_transition(v88, 6, v84, v80);
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_set_transition(v88, 7, v84, v80);
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_set_transition(v88, 8, v84, v80);
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_set_transition(v88, 9, v84, v80);
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|
_set_transition(v88, 10, v84, v80);
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_set_transition(v88, 11, v84, v80);
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_set_transition(v88, 12, v84, v80);
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_set_transition(v88, 13, v84, v80);
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|
_set_transition(v88, 14, v84, v80);
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_set_transition(v88, 15, v84, v80);
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_set_transition(v88, 16, v84, v80);
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_set_transition(v88, 17, v84, v80);
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_set_transition(v88, 18, v84, v80);
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_set_transition(v88, 19, v84, v80);
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_set_transition(v88, 20, v84, v80);
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_set_transition(v88, 21, v84, v80);
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_set_transition(v88, 22, v84, v80);
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end;
|
|
|
|
|
|
# The transition table describes transitions from one state to another, given
|
|
# a symbol (character class).
|
|
#
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|
# The table has m rows and n columns, where m is the amount of states and n is
|
|
# the amount of classes. So given the current state and a classified character
|
|
# the table can be used to look up the next state.
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|
#
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|
# Each cell is a word long.
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|
# - The least significant byte of the word is a row number (beginning with 0).
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|
# It specifies the target state. "ff" means that this is an end state and no
|
|
# transition is possible.
|
|
# - The next byte is the action that should be performed when transitioning.
|
|
# For the meaning of actions see labels in the lex_next function, which
|
|
# handles each action.
|
|
proc _initialize_transitions();
|
|
begin
|
|
# Start state.
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|
_set_transition(1, 1, 1, 16);
|
|
_set_transition(1, 2, 2, 4);
|
|
_set_transition(1, 3, 2, 3);
|
|
_set_transition(1, 4, 3, 1);
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|
_set_transition(1, 5, 2, 5);
|
|
_set_transition(1, 6, 4, 16);
|
|
_set_transition(1, 7, 2, 7);
|
|
_set_transition(1, 8, 4, 16);
|
|
_set_transition(1, 9, 4, 16);
|
|
_set_transition(1, 10, 2, 3);
|
|
_set_transition(1, 11, 4, 16);
|
|
_set_transition(1, 12, 2, 3);
|
|
_set_transition(1, 13, 2, 14);
|
|
_set_transition(1, 14, 2, 3);
|
|
_set_transition(1, 15, 5, 16);
|
|
_set_transition(1, 16, 2, 9);
|
|
_set_transition(1, 17, 2, 6);
|
|
_set_transition(1, 18, 2, 12);
|
|
_set_transition(1, 19, 2, 13);
|
|
_set_transition(1, 20, 2, 5);
|
|
_set_transition(1, 21, 2, 8);
|
|
_set_transition(1, 22, 1, 16);
|
|
|
|
# Colon state.
|
|
_set_default_transition(2, 6, 16);
|
|
_set_transition(2, 6, 7, 16);
|
|
|
|
# Identifier state.
|
|
_set_default_transition(3, 8, 16);
|
|
_set_transition(3, 2, 2, 3);
|
|
_set_transition(3, 3, 2, 3);
|
|
_set_transition(3, 10, 2, 3);
|
|
_set_transition(3, 12, 2, 3);
|
|
_set_transition(3, 13, 2, 3);
|
|
_set_transition(3, 14, 2, 3);
|
|
|
|
# Decimal state.
|
|
_set_default_transition(4, 9, 16);
|
|
_set_transition(4, 2, 2, 4);
|
|
_set_transition(4, 3, 2, 15);
|
|
_set_transition(4, 10, 1, 16);
|
|
_set_transition(4, 12, 2, 15);
|
|
_set_transition(4, 13, 2, 4);
|
|
_set_transition(4, 14, 2, 15);
|
|
|
|
# Greater state.
|
|
_set_default_transition(5, 6, 16);
|
|
_set_transition(5, 6, 7, 16);
|
|
|
|
# Minus state.
|
|
_set_default_transition(6, 6, 16);
|
|
_set_transition(6, 20, 7, 16);
|
|
|
|
# Left paren state.
|
|
_set_default_transition(7, 6, 16);
|
|
_set_transition(7, 9, 2, 10);
|
|
|
|
# Less state.
|
|
_set_default_transition(8, 6, 16);
|
|
_set_transition(8, 6, 7, 16);
|
|
_set_transition(8, 20, 7, 16);
|
|
|
|
# Hexadecimal after 0x.
|
|
_set_default_transition(9, 6, 16);
|
|
_set_transition(9, 16, 7, 16);
|
|
|
|
# Comment.
|
|
_set_default_transition(10, 2, 10);
|
|
_set_transition(10, 9, 2, 11);
|
|
_set_transition(10, 15, 1, 16);
|
|
|
|
# Closing comment.
|
|
_set_default_transition(11, 2, 10);
|
|
_set_transition(11, 1, 1, 16);
|
|
_set_transition(11, 8, 10, 16);
|
|
_set_transition(11, 9, 2, 11);
|
|
_set_transition(11, 15, 1, 16);
|
|
|
|
# Character.
|
|
_set_default_transition(12, 2, 12);
|
|
_set_transition(12, 1, 1, 16);
|
|
_set_transition(12, 15, 1, 16);
|
|
_set_transition(12, 18, 10, 16);
|
|
|
|
# String.
|
|
_set_default_transition(13, 2, 13);
|
|
_set_transition(13, 1, 1, 16);
|
|
_set_transition(13, 15, 1, 16);
|
|
_set_transition(13, 19, 10, 16);
|
|
|
|
# Leading zero.
|
|
_set_default_transition(14, 9, 16);
|
|
_set_transition(14, 2, 1, 16);
|
|
_set_transition(14, 3, 1, 16);
|
|
_set_transition(14, 10, 1, 16);
|
|
_set_transition(14, 12, 1, 16);
|
|
_set_transition(14, 13, 1, 16);
|
|
_set_transition(14, 14, 1, 16);
|
|
|
|
# Digit with a character suffix.
|
|
_set_default_transition(15, 9, 16);
|
|
_set_transition(15, 3, 1, 16);
|
|
_set_transition(15, 2, 1, 16);
|
|
_set_transition(15, 12, 1, 16);
|
|
_set_transition(15, 13, 1, 16);
|
|
_set_transition(15, 14, 1, 16);
|
|
end;
|
|
|
|
proc _lexer_get_state();
|
|
begin
|
|
# Lexer state is saved after the transition tables. The offset is 256 + 16 * 22.
|
|
v0 := @classification;
|
|
v4 := 16 * 22;
|
|
v0 := v0 + 256;
|
|
|
|
return v0 + v4
|
|
end;
|
|
|
|
# Gets pointer to the current source text.
|
|
proc _lexer_get_current();
|
|
begin
|
|
_lexer_get_state();
|
|
sw a0, 0(sp)
|
|
|
|
return v0 + 4
|
|
end;
|
|
|
|
# Resets the lexer state for reading the next token.
|
|
proc _lexer_reset();
|
|
begin
|
|
# Transition start state is 1.
|
|
_lexer_get_state();
|
|
li t0, 1
|
|
sw t0, (a0)
|
|
sw a0, 0(sp)
|
|
|
|
# Text pointer to the beginning of the currently read token.
|
|
_lexer_get_current();
|
|
la t0, source_code_position
|
|
lw t0, (t0)
|
|
sw t0, (a0)
|
|
|
|
# Initial length of the token is 0.
|
|
addi t0, t0, 4
|
|
sw zero, (t0)
|
|
end;
|
|
|
|
# One time lexer initialization.
|
|
proc _lexer_initialize();
|
|
begin
|
|
_initialize_classification();
|
|
_initialize_transitions();
|
|
end;
|
|
|
|
# Entry point.
|
|
proc _start();
|
|
begin
|
|
_lexer_initialize();
|
|
_symbol_table_build();
|
|
|
|
# Read the source from the standard input.
|
|
# Second argument is buffer size. Modifying update the source_code definition.
|
|
_read_file(@source_code, 81920);
|
|
_compile();
|
|
|
|
_exit(0);
|
|
end;
|