Move stages into subdirectories

1 files changed, 1989 insertions, 0 deletions

diff --git a/boot/stage8/cl.elna b/boot/stage8/cl.elna
new file mode 100644
index 0000000..75c24d7
--- /dev/null
+++ b/boot/stage8/cl.elna
@@ -0,0 +1,1989 @@
+# This Source Code Form is subject to the terms of the Mozilla Public License,
+# v. 2.0. If a copy of the MPL was not distributed with this file, You can
+# obtain one at https://mozilla.org/MPL/2.0/.
+
+# Stage 8 compiler.
+#
+# - Procedure calls in expressions.
+# - Comments between (* and *) are supported. These are still single line
+#   comments and they should be on a separate line.
+# - _syscall builtin. _syscall takes 7 arguments,
+#   the 7th argument gets stored in a7 before invoking ecall.
+#   Other arguments are saved in a0 through a5.
+# - New intrinsics: _load_byte, _load_word, _store_byte, _store_word.
+const
+	symbol_builtin_name_int := "Int";
+	symbol_builtin_name_word := "Word";
+	symbol_builtin_name_pointer := "Pointer";
+	symbol_builtin_name_char := "Char";
+	symbol_builtin_name_bool := "Bool";
+
+	# Every type info starts with a word describing what type it is.
+	#
+	# PRIMITIVE_TYPE = 1
+	#
+	# Primitive types have only type size.
+	symbol_builtin_type_int := S(1, 4);
+	symbol_builtin_type_word := S(1, 4);
+	symbol_builtin_type_pointer := S(1, 4);
+	symbol_builtin_type_char := S(1, 1);
+	symbol_builtin_type_bool := S(1, 1);
+
+	# Info objects start with a word describing its type.
+	#
+	# INFO_TYPE = 1
+	#
+	# Type info has the type it belongs to.
+	symbol_type_info_int := S(1, @symbol_builtin_type_int);
+	symbol_type_info_word := S(1, @symbol_builtin_type_word);
+	symbol_type_info_pointer := S(1, @symbol_builtin_type_pointer);
+	symbol_type_info_char := S(1, @symbol_builtin_type_char);
+	symbol_type_info_bool := S(1, @symbol_builtin_type_bool);
+
+var
+	source_code: Array;
+	compiler_strings: Array;
+	symbol_table_global: Array;
+	symbol_table_local: Array;
+	classification: Array;
+
+	compiler_strings_position: Pointer := @compiler_strings;
+	compiler_strings_length: Word := 0;
+	source_code_position: Pointer := @source_code;
+
+# Calculates and returns the string token length between quotes, including the
+# escaping slash characters.
+#
+# Parameters:
+# a0 - String token pointer.
+#
+# Returns the length in a0.
+proc _string_length();
+begin
+	# Reset the counter.
+	v0 := 0;
+
+.string_length_loop:
+	v88 := v88 + 1;
+
+	lw t0, 88(sp)
+	lb t0, (t0)
+
+	li t1, '"'
+	beq t0, t1, .string_length_end
+
+	v0 := v0 + 1;
+	goto .string_length_loop;
+
+.string_length_end:
+	return v0
+end;
+
+# Adds a string to the global, read-only string storage.
+#
+# Parameters:
+# a0 - String token.
+#
+# Returns the offset from the beginning of the storage to the new string in a0.
+proc _add_string();
+begin
+	v0 := v88 + 1;
+	v4 := compiler_strings_length;
+
+.add_string_loop:
+	lw t0, 0(sp)
+	lb t1, (t0)
+	li t2, '"'
+
+	beq t1, t2, .add_string_end
+
+	la t2, compiler_strings_position
+	lw t3, (t2)
+	sb t1, (t3)
+
+	addi t3, t3, 1
+	sw t3, (t2)
+
+	addi t0, t0, 1
+	sw t0, 0(sp)
+
+	li t2, '\\'
+	bne t1, t2, .add_string_increment
+
+	goto .add_string_loop;
+
+.add_string_increment:
+	la t2, compiler_strings_length
+	lw t4, (t2)
+	addi t4, t4, 1
+	sw t4, (t2)
+
+	goto .add_string_loop;
+
+.add_string_end:
+	return v4
+end;
+
+# Reads standard input into a buffer.
+# a0 - Buffer pointer.
+# a1 - Buffer size.
+#
+# Returns the amount of bytes written in a0.
+proc _read_file();
+begin
+	mv a2, a1
+	mv a1, a0
+	# STDIN.
+	li a0, 0
+	# SYS_READ.
+	li a7, 63
+	ecall
+end;
+
+# Writes to the standard output.
+#
+# Parameters:
+# a0 - Buffer.
+# a1 - Buffer length.
+proc _write_s();
+begin
+	mv a2, a1
+	mv a1, a0
+	# STDOUT.
+	li a0, 1
+	# SYS_WRITE.
+	li a7, 64
+	ecall
+end;
+
+# Writes a number to a string buffer.
+#
+# t0 - Local buffer.
+# t1 - Constant 10.
+# t2 - Current character.
+# t3 - Whether the number is negative.
+#
+# Parameters:
+# a0 - Whole number.
+# a1 - Buffer pointer.
+#
+# Sets a0 to the length of the written number.
+proc _print_i();
+begin
+	li t1, 10
+	addi t0, s0, -9
+
+	li t3, 0
+	bgez a0, .print_i_digit10
+	li t3, 1
+	neg a0, a0
+
+.print_i_digit10:
+	rem t2, a0, t1
+	addi t2, t2, '0'
+	sb t2, 0(t0)
+	div a0, a0, t1
+	addi t0, t0, -1
+	bne zero, a0, .print_i_digit10
+
+	beq zero, t3, .print_i_write_call
+	addi t2, zero, '-'
+	sb t2, 0(t0)
+	addi t0, t0, -1
+
+.print_i_write_call:
+	mv a0, a1
+	addi a1, t0, 1
+	sub a2, s0, t0
+	addi a2, a2, -9
+	sw a2, 0(sp)
+
+	_memcpy();
+
+	return v0
+end;
+
+# Writes a number to the standard output.
+#
+# Parameters:
+# a0 - Whole number.
+proc _write_i();
+begin
+	_print_i(v88, @v0);
+
+	mv a1, a0
+	addi a0, sp, 0
+	_write_s();
+
+end;
+
+# Writes a character from a0 into the standard output.
+proc _write_c();
+begin
+	_write_s(@v88, 1);
+end;
+
+# Write null terminated string.
+#
+# Parameters:
+# a0 - String.
+proc _write_z();
+begin
+.write_z_loop:
+	# Check for 0 character.
+	lw a0, 88(sp)
+	lb a0, (a0)
+	beqz a0, .write_z_end
+
+	# Print a character.
+	_write_c();
+
+	# Advance the input string by one byte.
+	v88 := v88 + 1;
+
+	goto .write_z_loop;
+
+.write_z_end:
+end;
+
+# Detects if a0 is an uppercase character. Sets a0 to 1 if so, otherwise to 0.
+proc _is_upper();
+begin
+	v0 := v88 >= 'A';
+	v4 := v88 <= 'Z';
+
+	return v0 & v4
+
+end;
+
+# Detects if a0 is an lowercase character. Sets a0 to 1 if so, otherwise to 0.
+proc _is_lower();
+begin
+	v0 := v88 >= 'a';
+	v4 := v88 <= 'z';
+
+	return v0 & v4
+
+end;
+
+# Detects if the passed character is a 7-bit alpha character or an underscore.
+#
+# Paramters:
+# a0 - Tested character.
+#
+# Sets a0 to 1 if the character is an alpha character or underscore, sets it to 0 otherwise.
+proc _is_alpha();
+begin
+	sw a0, 0(sp)
+
+	_is_upper();
+	sw a0, 4(sp)
+
+	_is_lower(v0);
+
+	lw t0, 0(sp)
+	xori t1, t0, '_'
+	seqz t1, t1
+
+	lw t0, 4(sp)
+	or a0, a0, t0
+	or a0, a0, t1
+end;
+
+# Detects whether the passed character is a digit
+# (a value between 0 and 9).
+#
+# Parameters:
+# a0 - Exemined value.
+#
+# Sets a0 to 1 if it is a digit, to 0 otherwise.
+proc _is_digit();
+begin
+	v0 := v88 >= '0';
+	v4 := v88 <= '9';
+
+	return v0 & v4
+end;
+
+proc _is_alnum();
+begin
+	sw a0, 4(sp)
+
+	_is_alpha();
+	sw a0, 0(sp)
+
+	_is_digit(v4);
+
+	lw a1, 0(sp)
+	or a0, a0, a1
+end;
+
+# Reads the next token.
+#
+# Returns token length in a0.
+proc _read_token();
+begin
+	# Current token position.
+	v0 := source_code_position;
+	# Token length.
+	v4 := 0;
+
+.read_token_loop:
+	lw t0, 0(sp)
+	# Current character.
+	lb t0, (t0)
+
+	# First we try to read a derictive.
+	# A derictive can contain a dot and characters.
+	li t1, '.'
+	beq t0, t1, .read_token_next
+
+	lw a0, 0(sp)
+	lb a0, (a0)
+	_is_alnum();
+	bnez a0, .read_token_next
+
+	goto .read_token_end;
+
+.read_token_next:
+	# Advance the source code position and token length.
+	v4 := v4 + 1;
+	v0 := v0 + 1;
+
+	goto .read_token_loop;
+
+.read_token_end:
+	return v4
+end;
+
+# a0 - First pointer.
+# a1 - Second pointer.
+# a2 - The length to compare.
+#
+# Returns 0 in a0 if memory regions are equal.
+proc _memcmp();
+begin
+	mv t0, a0
+	li a0, 0
+
+.memcmp_loop:
+	beqz a2, .memcmp_end
+
+	lbu t1, (t0)
+	lbu t2, (a1)
+	sub a0, t1, t2
+
+	bnez a0, .memcmp_end
+
+	addi t0, t0, 1
+	addi a1, a1, 1
+	addi a2, a2, -1
+
+	goto .memcmp_loop;
+
+.memcmp_end:
+end;
+
+# Copies memory.
+#
+# Parameters:
+# a0 - Destination.
+# a1 - Source.
+# a2 - Size.
+#
+# Preserves a0.
+proc _memcpy();
+begin
+	mv t0, a0
+
+.memcpy_loop:
+	beqz a2, .memcpy_end
+
+	lbu t1, (a1)
+	sb t1, (a0)
+
+	addi a0, a0, 1
+	addi a1, a1, 1
+	addi a2, a2, -1
+
+	goto .memcpy_loop
+
+.memcpy_end:
+	mv a0, t0
+end;
+
+# Advances the token stream by a0 bytes.
+proc _advance_token();
+begin
+	la t0, source_code_position
+	lw t1, (t0)
+	add t1, t1, a0
+	sw t1, (t0)
+end;
+
+# Prints the current token.
+#
+# Parameters:
+# a0 - Token length.
+#
+# Returns a0 unchanged.
+proc _write_token();
+begin
+	_write_s(source_code_position, v88);
+	return v88
+end;
+
+# Prints and skips a line.
+proc _compile_line();
+begin
+.compile_line_loop:
+	la a0, source_code_position
+	lw a1, (a0)
+
+	lb t0, (a1)
+	li t1, '\n'
+	beq t0, t1, .compile_line_end
+
+	# Print a character.
+	lw a0, (a1)
+	_write_c();
+
+	# Advance the input string by one byte.
+	_advance_token(1);
+
+	goto .compile_line_loop;
+
+.compile_line_end:
+	_write_c('\n');
+
+	_advance_token(1);
+end;
+
+proc _compile_integer_literal();
+begin
+	_write_z("\tli t0, \0");
+
+	_read_token();
+	_write_token();
+	_advance_token();
+
+	_write_c('\n');
+end;
+
+proc _compile_character_literal();
+begin
+	_write_z("\tli t0, \0");
+
+	_write_c('\'');
+	_advance_token(1);
+
+	la t0, source_code_position
+	lw t0, (t0)
+	lb a0, (t0)
+	li t1, '\\'
+	bne a0, t1, .compile_character_literal_end
+	
+	_write_c('\\');
+	_advance_token(1);
+
+.compile_character_literal_end:
+	la t0, source_code_position
+	lw t0, (t0)
+	lb a0, (t0)
+	_write_c();
+
+	_write_c('\'');
+	_write_c('\n');
+
+	_advance_token(2);
+
+end;
+
+proc _compile_variable_expression();
+begin
+	_compile_designator();
+	_write_z("\tlw t0, (t0)\n\0");
+end;
+
+proc _compile_address_expression();
+begin
+	# Skip the "@" sign.
+	_advance_token(1);
+	_compile_designator();
+
+end;
+
+proc _compile_negate_expression();
+begin
+	# Skip the "-" sign.
+	_advance_token(1);
+	_compile_term();
+
+	_write_z("\tneg t0, t0\n\0");
+end;
+
+proc _compile_not_expression();
+begin
+	# Skip the "~" sign.
+	_advance_token(1);
+	_compile_term();
+
+	_write_z("\tnot t0, t0\n\0");
+end;
+
+proc _compile_string_literal();
+begin
+	_string_length(source_code_position);
+	sw a0, 0(sp)
+
+	_add_string(source_code_position);
+	sw a0, 4(sp)
+
+	_advance_token(v0 + 2);
+	_write_z("\tla t0, strings\n\0");
+
+	_write_z("\tli t1, \0");
+	_write_i(v4);
+	_write_c('\n');
+
+	_write_z("\tadd t0, t0, t1\n\0");
+end;
+
+proc _compile_term();
+begin
+	la t0, source_code_position
+	lw t0, (t0)
+	lb a0, (t0)
+	sw a0, 0(sp)
+
+	li t1, '\''
+	beq a0, t1, .compile_term_character_literal
+
+	li t1, '@'
+	beq a0, t1, .compile_term_address
+
+	li t1, '-'
+	beq a0, t1, .compile_term_negation
+
+	li t1, '~'
+	beq a0, t1, .compile_term_not
+
+	li t1, '"'
+	beq a0, t1, .compile_term_string_literal
+
+	li t1, '_'
+	beq a0, t1, .compile_term_call
+
+	_is_digit(v0);
+	bnez a0, .compile_term_integer_literal
+
+	goto .compile_term_variable;
+
+.compile_term_character_literal:
+	_compile_character_literal();
+	goto .compile_term_end;
+
+.compile_term_integer_literal:
+	_compile_integer_literal();
+	goto .compile_term_end;
+
+.compile_term_address:
+	_compile_address_expression();
+	goto .compile_term_end;
+
+.compile_term_negation:
+	_compile_negate_expression();
+	goto .compile_term_end;
+
+.compile_term_not:
+	_compile_not_expression();
+	goto .compile_term_end;
+
+.compile_term_string_literal:
+	_compile_string_literal();
+	goto .compile_term_end;
+
+.compile_term_call:
+	_compile_call();
+	_write_z("\nmv t0, a0\n\0");
+	goto .compile_term_end;
+
+.compile_term_variable:
+	_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\n\0");
+	_write_z(".type _syscall, @function\n_syscall:\n\tmv a7, a6\n\tecall\n\tret\n\n\0");
+	_write_z(".type _load_byte, @function\n_load_byte:\n\tlb a0, (a0)\nret\n\n\0");
+	_write_z(".type _load_word, @function\n_load_word:\n\tlw a0, (a0)\nret\n\n\0");
+	_write_z(".type _store_byte, @function\n_store_byte:\n\tsb a0, (a1)\nret\n\n\0");
+	_write_z(".type _store_word, @function\n_store_word:\n\tsw a0, (a1)\nret\n\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:
+# a0 - Current state (first index into transitions table).
+# a1 - Transition (second index into transitions table)..
+# a2 - Action to assign.
+# a3 - Next state to assign.
+proc _set_transition();
+begin
+	# Transitions start at offset in classification array. Save the transitions start in v0.
+	la t0, classification
+	addi t0, t0, 256
+	sw t0, 0(sp)
+
+	# Each state is 8 bytes long (2 words: action and next state).
+	# There are 16 transition classes, so a transition 8 * 16 = 128 bytes long.
+
+	v4 := v88 + -1;
+	v4 := v4 * 128;
+
+	v8 := v84 + -1;
+	v8 := v8 * 8;
+
+	v12 := v0 + v4;
+	v12 := v12 + v8;
+
+	lw t0, 12(sp)
+	lw t1, 80(sp)
+	lw t2, 76(sp)
+	sw t1, (t0)
+	addi t0, t0, 4
+	sw t2, (t0)
+end;
+
+# Parameters:
+# a0 - Current state (Transition state enumeration).
+# a1 - Default action (Callback).
+# a2 - Next state (Transition state enumeration).
+proc _set_default_transition();
+begin
+	_set_transition(v88, 1, v84, v80);
+	_set_transition(v88, 2, v84, v80);
+	_set_transition(v88, 3, v84, v80);
+	_set_transition(v88, 4, v84, v80);
+	_set_transition(v88, 5, v84, v80);
+	_set_transition(v88, 6, v84, v80);
+	_set_transition(v88, 7, v84, v80);
+	_set_transition(v88, 8, v84, v80);
+	_set_transition(v88, 9, v84, v80);
+	_set_transition(v88, 10, v84, v80);
+	_set_transition(v88, 11, v84, v80);
+	_set_transition(v88, 12, v84, v80);
+	_set_transition(v88, 13, v84, v80);
+	_set_transition(v88, 14, v84, v80);
+	_set_transition(v88, 15, v84, v80);
+	_set_transition(v88, 16, v84, v80);
+	_set_transition(v88, 17, v84, v80);
+	_set_transition(v88, 18, v84, v80);
+	_set_transition(v88, 19, v84, v80);
+	_set_transition(v88, 20, v84, v80);
+	_set_transition(v88, 21, v84, v80);
+	_set_transition(v88, 22, v84, v80);
+end;
+
+
+# The transition table describes transitions from one state to another, given
+# a symbol (character class).
+#
+# 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.
+#
+# Each cell is a word long.
+# - The least significant byte of the word is a row number (beginning with 0).
+#   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.
+	_set_transition(1, 1, 1, 16);
+	_set_transition(1, 2, 2, 4);
+	_set_transition(1, 3, 2, 3);
+	_set_transition(1, 4, 3, 1);
+	_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;