1160 lines
20 KiB
Plaintext
1160 lines
20 KiB
Plaintext
program
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# s1 - Contains the current position in the source text.
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const
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SOURCE_BUFFER_SIZE := 20480
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var
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source_code: [20480]Byte
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.section .text
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# Evalutes an expression and saves the result in a0.
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proc _build_expression()
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begin
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_skip_spaces()
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call _read_token
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sw s1, 20(sp)
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sw a0, 16(sp)
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# Integer literal.
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addi a0, s1, 0
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lb a0, (a0)
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call _is_digit
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bnez a0, .Lbuild_expression_number_literal
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# Named identifier.
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li t0, 0x202c30 # 0,_
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sw t0, 12(sp)
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li t0, 0x6120616c # la a
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sw t0, 8(sp)
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addi a0, sp, 8
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li a1, 7
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call _write_out
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lw a0, 20(sp)
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lw a1, 16(sp)
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call _write_out
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li t0, 0x0a # \n
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sw t0, 12(sp)
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addi a0, sp, 12
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li a1, 1
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call _write_out
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j .Lbuild_expression_end
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.Lbuild_expression_number_literal:
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li t0, 0x202c30 # 0,_
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sw t0, 12(sp)
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li t0, 0x6120696c # li a
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sw t0, 8(sp)
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addi a0, sp, 8
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li a1, 7
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call _write_out
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lw a0, 20(sp)
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lw a1, 16(sp)
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call _write_out
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li t0, 0x0a # \n
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sw t0, 12(sp)
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addi a0, sp, 12
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li a1, 1
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call _write_out
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j .Lbuild_expression_end
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.Lbuild_expression_end:
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lw a0, 16(sp)
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add s1, s1, a0
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end
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# Compiles a statement beginning with an identifier.
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#
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# Left values should be variables named "loca n", where n is the offset
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# of the variable on the stack, like loca8 or loca4.
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proc _compile_identifier()
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begin
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call _read_token
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# Save the pointer to the identifier and its length on the stack.
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sw s1, 20(sp)
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sw a0, 16(sp)
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add s1, s1, a0
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_skip_spaces()
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call _read_token
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# Save the pointer and the length of the token following the identifier.
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sw s1, 12(sp)
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sw a0, 8(sp)
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add s1, s1, a0 # Skip that token.
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_skip_spaces()
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li t0, 0x3d3a # :=
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sw t0, 4(sp)
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lw a0, 12(sp)
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lw a1, 8(sp)
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addi a2, sp, 4
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call _token_compare
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beqz a0, .Lcompile_identifier_assign
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/* DEBUG
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mv a0, s1
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li a1, 4
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call _write_error */
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lw t0, 12(sp)
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lbu t0, (t0)
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li t1, 0x28 # (
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beq t0, t1, .Lcompile_identifier_call
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j .Lcompile_identifier_end
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.Lcompile_identifier_call:
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lw a0, 20(sp)
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lw a1, 16(sp)
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call _compile_call
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j .Lcompile_identifier_end
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.Lcompile_identifier_assign:
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call _build_expression
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li t0, 0x202c30 # 0,_
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sw t0, 12(sp)
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li t0, 0x61207773 # sw a
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sw t0, 8(sp)
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addi a0, sp, 8
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li a1, 7
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call _write_out
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lw a0, 20(sp)
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lw a1, 16(sp)
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addi a0, a0, 4 # Skip the "loca" variable prefix.
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addi a1, a1, -4 # Skip the "loca" variable prefix.
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call _write_out
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li t0, 0x0a # \n
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sw t0, 12(sp)
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li t0, 0x29707328 # (sp)
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sw t0, 8(sp)
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addi a0, sp, 8
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li a1, 5
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call _write_out
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j .Lcompile_identifier_end
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.Lcompile_identifier_end:
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end
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# Compiles a procedure call. Expects s1 to point to the first argument.
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# a0 - Pointer to the procedure name.
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# a1 - Length of the procedure name.
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#
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# Returns the procedure result in a0.
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proc _compile_call()
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begin
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sw a0, 20(sp)
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sw a1, 16(sp)
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sw zero, 12(sp) # Argument count for a procedure call.
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.Lcompile_call_paren:
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_skip_spaces()
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call _read_token
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lbu t0, (s1)
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li t1, 0x29 # )
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beq t0, t1, .Lcompile_call_complete
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.Lcompile_call_argument:
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call _build_expression
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li t0, 0x202c30 # 0,_
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sw t0, 8(sp)
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li t0, 0x61207773 # sw a
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sw t0, 4(sp)
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addi a0, sp, 4
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li a1, 7
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call _write_out
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lw t0, 12(sp) # Argument count for a procedure call.
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# Only 8 arguments are supported with a0-a7.
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# Save all arguments on the stack so they aren't overriden afterwards.
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# The offset on the stack always has two digits in this case.
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li t1, -4
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mul t1, t0, t1
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addi t1, t1, 84
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li t2, 10
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div t3, t1, t2
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rem t4, t1, t2
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addi t3, t3, '0'
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addi t4, t4, '0'
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sw t3, 8(sp)
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sw t4, 4(sp)
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addi a0, sp, 8
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li a1, 1
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call _write_out
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addi a0, sp, 4
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li a1, 1
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call _write_out
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li t0, 0x0a # \n
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sw t0, 8(sp)
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li t0, 0x29707328 # (sp)
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sw t0, 4(sp)
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addi a0, sp, 4
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li a1, 5
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call _write_out
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_skip_spaces()
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call _read_token
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lbu t0, (s1)
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li t1, ','
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bne t0, t1, .Lcompile_call_paren
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lw t0, 12(sp) # Argument count for a procedure call.
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addi t0, t0, 1
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sw t0, 12(sp)
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_advance(1) # Skip the comma between the arguments.
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j .Lcompile_call_argument
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.Lcompile_call_complete:
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sw zero, 12(sp)
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.Lcompile_call_restore:
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# Just go through all a0-a7 registers and read them from stack.
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# If this stack value contains garbage, the procedure just shouldn't use it.
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lw t0, 12(sp)
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li t1, 7
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bgt t0, t1, .Lcompile_call_perform
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li t0, 0x6120776c # lw a
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sw t0, 4(sp)
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addi a0, sp, 4
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li a1, 4
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call _write_out
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lw t0, 12(sp) # Argument count for a procedure call.
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li t1, -4
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mul t1, t0, t1
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addi t1, t1, 84
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li t2, 10
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div t3, t1, t2
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rem t4, t1, t2
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addi t3, t3, '0'
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addi t4, t4, '0'
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addi t0, t0, '0'
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li t5, 0x0a # \n
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sb t5, 11(sp)
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li t5, 0x29707328 # (sp)
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sw t5, 7(sp)
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sb t4, 6(sp)
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sb t3, 5(sp)
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li t5, 0x202c # ,_
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sh t5, 3(sp)
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sb t0, 2(sp)
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addi a0, sp, 2
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li a1, 10
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call _write_out
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lw t0, 12(sp) # Increment.
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addi t0, t0, 1
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sw t0, 12(sp)
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j .Lcompile_call_restore
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.Lcompile_call_perform:
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li t0, 0x20
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sw t0, 8(sp)
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li t0, 0x6c6c6163
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sw t0, 4(sp)
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addi a0, sp, 4
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li a1, 5
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call _write_out
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lw a0, 20(sp)
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lw a1, 16(sp)
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call _write_out
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li t0, 0x0a # \n
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sw t0, 8(sp)
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addi a0, sp, 8
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li a1, 1
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call _write_out
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_skip_spaces()
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_advance(1) # Skip the close paren.
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end
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# Reads a token and returns its length in a0.
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# _read_token doesn't change s1, it finds the length of the token s1 is pointing to.
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proc _read_token()
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begin
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lbu t0, (s1) # t0 = Current character.
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sw zero, 4(sp)
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li t1, '.'
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beq t0, t1, .Ltoken_character_single
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li t1, ','
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beq t0, t1, .Ltoken_character_single
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li t1, ':'
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beq t0, t1, .Ltoken_character_colon
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li t1, ';'
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beq t0, t1, .Ltoken_character_single
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li t1, '('
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beq t0, t1, .Ltoken_character_single
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li t1, ')'
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beq t0, t1, .Ltoken_character_single
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li t1, '['
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beq t0, t1, .Ltoken_character_single
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li t1, ']'
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beq t0, t1, .Ltoken_character_single
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.Ltoken_character_loop_do: # Expect an identifier or a number.
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lw t6, 4(sp)
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add t1, s1, t6
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lbu a0, (t1) # a0 = Current character.
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call _is_alnum
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beqz a0, .Ltoken_character_end
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lw t6, 4(sp)
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addi t6, t6, 1
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sw t6, 4(sp)
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j .Ltoken_character_loop_do
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.Ltoken_character_single:
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lw t6, 4(sp)
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addi t6, t6, 1
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sw t6, 4(sp)
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j .Ltoken_character_end
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.Ltoken_character_colon:
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lbu t0, 1(s1) # t0 = The character after the colon.
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lw t6, 4(sp)
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addi t6, t6, 1
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sw t6, 4(sp)
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li t1, '='
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beq t0, t1, .Ltoken_character_single
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j .Ltoken_character_end
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.Ltoken_character_end:
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lw a0, 4(sp)
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end
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# Skips the spaces till the next non space character.
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proc _skip_spaces()
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begin
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.Lspace_loop_do:
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lbu t0, (s1) # t0 = Current character.
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li t1, ' '
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beq t0, t1, .Lspace_loop_repeat
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li t1, '\t'
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beq t0, t1, .Lspace_loop_repeat
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li t1, '\n'
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beq t0, t1, .Lspace_loop_repeat
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li t1, '\r'
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beq t0, t1, .Lspace_loop_repeat
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j .Lspace_loop_end
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.Lspace_loop_repeat:
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_advance(1)
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j .Lspace_loop_do
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.Lspace_loop_end:
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end
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# Skips tabs at the line beginning.
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proc _skip_indentation()
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begin
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.Lskip_indentation_do:
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lbu t0, (s1)
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li t1, '\t'
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beq t0, t1, .Lskip_indentation_skip
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j .Lskip_indentation_end
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.Lskip_indentation_skip:
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_advance(1)
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j .Lskip_indentation_do
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.Lskip_indentation_end:
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end
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# Parameters:
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# a0 - Line length.
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proc _skip_comment()
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begin
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add s1, s1, a0
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_advance(1) # Skip the new line.
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end
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# Parameters:
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# a0 - Line length.
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proc _compile_assembly()
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begin
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sw a0, 4(sp) # a0 - Line length.
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# Write the source to the standard output.
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mv a0, s1
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lw a1, 4(sp)
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call _write_out
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lw t0, 4(sp)
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add s1, s1, t0
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li t0, '\n'
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sb t0, 0(sp)
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addi a0, sp, 0
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li a1, 1
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call _write_out
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_advance(1) # Skip the new line.
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end
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proc _compile_program()
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begin
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# .global _start
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li t0, 0x0a7472 # rt\n
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sw t0, 20(sp)
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li t0, 0x6174735f # _sta
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sw t0, 16(sp)
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li t0, 0x206c6162 # bal_
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sw t0, 12(sp)
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li t0, 0x6f6c672e # .glo
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sw t0, 8(sp)
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addi a0, sp, 8
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li a1, 15
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call _write_out
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_advance(8) # program\n.
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end
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proc _compile_constant_section()
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begin
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# .section .rodata
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li t0, 0x0a # \n
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sw t0, 20(sp)
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li t0, 0x61746164 # data
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sw t0, 16(sp)
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li t0, 0x6f722e20 # _.ro
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sw t0, 12(sp)
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li t0, 0x6e6f6974 # tion
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sw t0, 8(sp)
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li t0, 0x6365732e # .sec
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sw t0, 4(sp)
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addi a0, sp, 4
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li a1, 17
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call _write_out
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_advance(6) # const\n.
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.Lcompile_constant_section_item:
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_skip_spaces()
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lbu a0, (s1)
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call _is_upper
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beqz a0, .Lcompile_constant_section_end
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call _compile_constant
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j .Lcompile_constant_section_item
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.Lcompile_constant_section_end:
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end
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proc _compile_constant()
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begin
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call _read_token
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mv a1, a0 # The identifier length from _read_token should be in a1.
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mv a0, s1 # Save the identifier pointer before advancing it.
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add s1, s1, a1
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call _write_out
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_skip_spaces()
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call _read_token
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_advance(2) # Skip the assignment sign.
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# : .long
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li t0, 0x20676e6f # ong_
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sw t0, 4(sp)
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li t0, 0x6c2e203a # : .l
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sw t0, 0(sp)
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mv a0, sp
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li a1, 8
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call _write_out
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_skip_spaces()
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call _read_token
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mv a1, a0 # The literal length from _read_token should be in a1.
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mv a0, s1 # Save the literal pointer before advancing it.
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add s1, s1, a1
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call _write_out
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li t0, '\n'
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sw t0, 4(sp)
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addi a0, sp, 4
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li a1, 1
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call _write_out
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end
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proc _compile_variable_section()
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begin
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# .section .bss
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li t0, 0x0a73 # s\n
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sw t0, 12(sp)
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li t0, 0x73622e20 # _.bs
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sw t0, 8(sp)
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li t0, 0x6e6f6974 # tion
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sw t0, 4(sp)
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li t0, 0x6365732e # .sec
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sw t0, 0(sp)
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addi a0, sp, 0
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li a1, 14
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call _write_out
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_advance(4) # var\n.
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.Lcompile_variable_section_item:
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_skip_spaces()
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lbu a0, (s1)
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call _is_lower
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beqz a0, .Lcompile_variable_section_end
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call _compile_variable
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j .Lcompile_variable_section_item
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.Lcompile_variable_section_end:
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end
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proc _compile_variable()
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begin
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call _read_token
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# Save the identifier on the stack since it should emitted multiple times.
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sw s1, 28(sp)
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sw a0, 24(sp)
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add s1, s1, a0
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_skip_spaces()
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_advance(1) # Skip the colon in front of the type.
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_skip_spaces()
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_advance(1) # Skip the opening bracket.
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call _read_token
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# Save the array size on the stack since it has to be emitted multiple times.
|
|
sw s1, 20(sp)
|
|
sw a0, 16(sp)
|
|
add s1, s1, a0
|
|
|
|
_skip_spaces()
|
|
_advance(1) # Skip the closing bracket.
|
|
|
|
_skip_spaces()
|
|
call _read_token
|
|
add s1, s1, a0 # Skip the type.
|
|
|
|
# .type identifier, @object
|
|
li t0, 0x2065 # e_
|
|
sw t0, 12(sp)
|
|
li t0, 0x7079742e # .typ
|
|
sw t0, 8(sp)
|
|
addi a0, sp, 8
|
|
li a1, 6
|
|
call _write_out
|
|
|
|
lw a0, 28(sp)
|
|
lw a1, 24(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x0a74 # t\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x63656a62 # bjec
|
|
sw t0, 8(sp)
|
|
li t0, 0x6f40202c # , @o
|
|
sw t0, 4(sp)
|
|
addi a0, sp, 4
|
|
li a1, 10
|
|
call _write_out
|
|
|
|
# .size identifier, size
|
|
li t0, 0x2065 # e_
|
|
sw t0, 12(sp)
|
|
li t0, 0x7a69732e # .siz
|
|
sw t0, 8(sp)
|
|
addi a0, sp, 8
|
|
li a1, 6
|
|
call _write_out
|
|
|
|
lw a0, 28(sp)
|
|
lw a1, 24(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x202c # ,
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 2
|
|
call _write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x0a # \n
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 1
|
|
call _write_out
|
|
|
|
# identifier: .zero size
|
|
lw a0, 28(sp)
|
|
lw a1, 24(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x206f7265 # ero_
|
|
sw t0, 12(sp)
|
|
li t0, 0x7a2e203a # : .z
|
|
sw t0, 8(sp)
|
|
addi a0, sp, 8
|
|
li a1, 8
|
|
call _write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x0a # \n
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 1
|
|
call _write_out
|
|
end
|
|
|
|
proc _compile_procedure()
|
|
begin
|
|
_advance(5) # Skip proc_
|
|
call _read_token
|
|
sw s1, 20(sp)
|
|
sw a0, 16(sp)
|
|
add s1, s1, a0
|
|
|
|
# .type identifier, @function
|
|
li t0, 0x2065 # e_
|
|
sw t0, 12(sp)
|
|
li t0, 0x7079742e # .typ
|
|
sw t0, 8(sp)
|
|
addi a0, sp, 8
|
|
li a1, 6
|
|
call _write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x0a6e6f69 # ion\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x74636e75 # unct
|
|
sw t0, 8(sp)
|
|
li t0, 0x6640202c # , @f
|
|
sw t0, 4(sp)
|
|
addi a0, sp, 4
|
|
li a1, 12
|
|
call _write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call _write_out
|
|
|
|
li t0, 0x0a3a # :\n
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 2
|
|
call _write_out
|
|
|
|
_skip_spaces()
|
|
_advance(1) # Skip opening argument paren.
|
|
_skip_spaces()
|
|
_advance(1) # Skip closing argument paren.
|
|
|
|
li t0, 0x6e # n
|
|
sw t0, 12(sp)
|
|
li t0, 0x69676562 # begi
|
|
sw t0, 8(sp)
|
|
|
|
# Skip all declarations until we find the "begin" keyword, denoting the
|
|
# beginning of the procedure body.
|
|
.Lcompile_procedure_begin:
|
|
_skip_spaces()
|
|
call _read_token
|
|
|
|
mv a1, a0
|
|
mv a0, s1
|
|
addi a2, sp, 8
|
|
add s1, s1, a1
|
|
call _token_compare
|
|
|
|
bnez a0, .Lcompile_procedure_begin
|
|
|
|
# Generate the procedure prologue with a predefined stack size.
|
|
li t0, 0x69646461 # addi
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
li t0, 0x2c707320 # _sp,
|
|
sw t0, 12(sp)
|
|
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
li t0, 0x0a36392d # -96\n
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
li t0, 0x0a29 # )\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x70732832 # 2(sp
|
|
sw t0, 8(sp)
|
|
li t0, 0x39202c61 # a, 9
|
|
sw t0, 4(sp)
|
|
li t0, 0x72207773 # sw r
|
|
sw t0, 0(sp)
|
|
addi a0, sp, 0
|
|
li a1, 14
|
|
call _write_out
|
|
|
|
li t0, 0x0a29 # )\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x70732838 # 2(sp
|
|
sw t0, 8(sp)
|
|
li t0, 0x38202c30 # 0, 8
|
|
sw t0, 4(sp)
|
|
li t0, 0x73207773 # sw s
|
|
sw t0, 0(sp)
|
|
addi a0, sp, 0
|
|
li a1, 14
|
|
call _write_out
|
|
|
|
li t0, 0x0a363920 # _96\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x2c707320 # _sp,
|
|
sw t0, 8(sp)
|
|
li t0, 0x2c307320 # _s0,
|
|
sw t0, 4(sp)
|
|
li t0, 0x69646461 # addi
|
|
sw t0, 0(sp)
|
|
addi a0, sp, 0
|
|
li a1, 16
|
|
call _write_out
|
|
|
|
# Generate the body of the procedure.
|
|
.Lcompile_procedure_body:
|
|
_skip_indentation()
|
|
call _read_line
|
|
sw a0, 12(sp)
|
|
li t0, 0x0a646e65 # end\n
|
|
sw t0, 8(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 8
|
|
li a2, 4
|
|
call _memcmp
|
|
|
|
beqz a0, .Lcompile_procedure_end
|
|
|
|
lw a0, 12(sp)
|
|
call _compile_line
|
|
j .Lcompile_procedure_body
|
|
|
|
.Lcompile_procedure_end:
|
|
add s1, s1, 4 # Skip end\n.
|
|
|
|
# Generate the procedure epilogue with a predefined stack size.
|
|
li t0, 0x0a29 # )\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x70732832 # 2(sp
|
|
sw t0, 8(sp)
|
|
li t0, 0x39202c61 # a, 9
|
|
sw t0, 4(sp)
|
|
li t0, 0x7220776c # lw r
|
|
sw t0, 0(sp)
|
|
addi a0, sp, 0
|
|
li a1, 14
|
|
call _write_out
|
|
|
|
li t0, 0x0a29 # )\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x70732838 # 2(sp
|
|
sw t0, 8(sp)
|
|
li t0, 0x38202c30 # 0, 8
|
|
sw t0, 4(sp)
|
|
li t0, 0x7320776c # lw s
|
|
sw t0, 0(sp)
|
|
addi a0, sp, 0
|
|
li a1, 14
|
|
call _write_out
|
|
|
|
li t0, 0x69646461 # addi
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
li t0, 0x2c707320 # _sp,
|
|
sw t0, 12(sp)
|
|
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
|
|
li t0, 0x0a3639 # 96\n
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 3
|
|
call _write_out
|
|
|
|
li t0, 0x0a746572 # ret\n
|
|
sw t0, 12(sp)
|
|
addi a0, sp, 12
|
|
li a1, 4
|
|
call _write_out
|
|
end
|
|
|
|
# Compares two string, which of one has a length, the other one is null-terminated.
|
|
#
|
|
# a0 - The address of the token string.
|
|
# a1 - The length of the string in a0.
|
|
# a2 - The address of the null-terminated string.
|
|
#
|
|
# If the strings match sets a0 to 0, otherwise sets it to 1.
|
|
proc _token_compare()
|
|
begin
|
|
addi t0, a0, 0
|
|
addi t1, a1, 0
|
|
addi t2, a2, 0
|
|
|
|
.Ltoken_compare_loop:
|
|
lbu t3, (t2)
|
|
|
|
# Will only be 0 if the current character in the null terminated string is \0 and the remaining length of the
|
|
# another string is 0.
|
|
or t4, t3, t1
|
|
beqz t4, .Ltoken_compare_equal
|
|
|
|
beqz t1, .Ltoken_compare_not_equal
|
|
beqz t3, .Ltoken_compare_not_equal
|
|
|
|
lbu t4, (t0)
|
|
bne t3, t4, .Ltoken_compare_not_equal
|
|
|
|
addi t0, t0, 1
|
|
addi t1, t1, -1
|
|
addi t2, t2, 1
|
|
j .Ltoken_compare_loop
|
|
|
|
.Ltoken_compare_not_equal:
|
|
li a0, 1
|
|
j .Ltoken_compare_end
|
|
|
|
.Ltoken_compare_equal:
|
|
li a0, 0
|
|
|
|
.Ltoken_compare_end:
|
|
end
|
|
|
|
# Parameters:
|
|
# a0 - Line length.
|
|
# Returns 1 in a0 if the parsed line contained a text section element such a
|
|
# procedure or the program entry point. Otherwise sets a0 to 0.
|
|
proc _compile_line()
|
|
begin
|
|
sw a0, 20(sp) # a0 - Line length.
|
|
|
|
beqz a0, .Lcompile_line_empty # Skip an empty line.
|
|
|
|
lbu t0, (s1)
|
|
li t1, '#'
|
|
beq t0, t1, .Lcompile_line_comment
|
|
|
|
li t0, 0x0a6d6172 # ram\n
|
|
sw t0, 16(sp)
|
|
li t0, 0x676f7270 # prog
|
|
sw t0, 12(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 12
|
|
li a2, 8
|
|
call _memcmp
|
|
beqz a0, .Lcompile_line_program
|
|
|
|
li t0, 0x0a74 # t\n
|
|
sw t0, 16(sp)
|
|
li t0, 0x736e6f63 # cons
|
|
sw t0, 12(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 12
|
|
li a2, 6
|
|
call _memcmp
|
|
beqz a0, .Lcompile_line_const
|
|
|
|
li t0, 0x0a726176 # var\n
|
|
sw t0, 16(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 16
|
|
li a2, 4
|
|
call _memcmp;
|
|
beqz a0, .Lcompile_line_var
|
|
|
|
li t0, 0x20 # _
|
|
sw t0, 16(sp)
|
|
li t0, 0x636f7270 # proc
|
|
sw t0, 12(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 12
|
|
li a2, 5
|
|
call _memcmp
|
|
beqz a0, .Lcompile_line_procedure
|
|
|
|
li t0, 0x0a6e # n\n
|
|
sw t0, 16(sp)
|
|
li t0, 0x69676562 # begi
|
|
sw t0, 12(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 12
|
|
li a2, 6
|
|
call _memcmp
|
|
beqz a0, .Lcompile_line_begin
|
|
|
|
li t0, 0x2e646e65 # end.
|
|
sw t0, 16(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 16
|
|
li a2, 4
|
|
call _memcmp
|
|
beqz a0, .Lcompile_line_exit
|
|
|
|
li t0, 0x61636f6c # loca
|
|
sw t0, 16(sp)
|
|
mv a0, s1
|
|
addi a1, sp, 16
|
|
li a2, 4
|
|
call _memcmp
|
|
beqz a0, .Lcompile_line_identifier
|
|
|
|
lbu t0, (s1)
|
|
li t1, '_'
|
|
beq t0, t1, .Lcompile_line_identifier
|
|
|
|
j .Lcompile_line_unchanged # Else.
|
|
|
|
.Lcompile_line_identifier:
|
|
call _compile_identifier
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_exit:
|
|
call _compile_exit
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_begin:
|
|
call _compile_entry_point
|
|
li a0, 1
|
|
j .Lcompile_line_end
|
|
|
|
.Lcompile_line_const:
|
|
call _compile_constant_section
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_procedure:
|
|
call _compile_procedure
|
|
li a0, 1
|
|
j .Lcompile_line_end
|
|
|
|
.Lcompile_line_var:
|
|
call _compile_variable_section
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_program:
|
|
call _compile_program
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_comment:
|
|
lw a0, 20(sp)
|
|
call _skip_comment
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_empty:
|
|
_advance(1)
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_unchanged:
|
|
lw a0, 20(sp)
|
|
call _compile_assembly
|
|
j .Lcompile_line_section
|
|
|
|
.Lcompile_line_section:
|
|
mv a0, zero
|
|
|
|
.Lcompile_line_end:
|
|
end
|
|
|
|
proc _compile_text_section()
|
|
begin
|
|
# .section .text
|
|
li t0, 0x0a7478 # xt\n
|
|
sw t0, 12(sp)
|
|
li t0, 0x65742e20 # _.te
|
|
sw t0, 8(sp)
|
|
li t0, 0x6e6f6974 # tion
|
|
sw t0, 4(sp)
|
|
li t0, 0x6365732e # .sec
|
|
sw t0, 0(sp)
|
|
|
|
addi a0, sp, 0
|
|
li a1, 15
|
|
call _write_out
|
|
end
|
|
|
|
proc _compile_entry_point()
|
|
begin
|
|
# .type _start, @function
|
|
li t0, 0x0a3a7472 # rt:\n
|
|
sw t0, 52(sp)
|
|
li t0, 0x6174735f # _sta
|
|
sw t0, 48(sp)
|
|
li t0, 0x0a6e6f69 # ion\n
|
|
sw t0, 44(sp)
|
|
li t0, 0x74636e75 # unct
|
|
sw t0, 40(sp)
|
|
li t0, 0x6640202c # , @f
|
|
sw t0, 36(sp)
|
|
li t0, 0x74726174 # tart
|
|
sw t0, 32(sp)
|
|
li t0, 0x735f2065 # e _s
|
|
sw t0, 28(sp)
|
|
li t0, 0x7079742e # .typ
|
|
sw t0, 24(sp)
|
|
addi a0, sp, 24
|
|
li a1, 32
|
|
call _write_out
|
|
|
|
_advance(6) # Skip begin\n.
|
|
end
|
|
|
|
proc _compile_exit()
|
|
begin
|
|
# li a0, 0
|
|
# li a7, SYS_EXIT
|
|
# ecall
|
|
li t0, 0x0a # \n
|
|
sw t0, 52(sp)
|
|
li t0, 0x6c6c6163 # call
|
|
sw t0, 48(sp)
|
|
li t0, 0x650a3339 # 93\ne
|
|
sw t0, 44(sp)
|
|
li t0, 0x202c3761 # a7,_
|
|
sw t0, 40(sp)
|
|
li t0, 0x20696c0a # \nli_
|
|
sw t0, 36(sp)
|
|
li t0, 0x30202c30 # 0, 0
|
|
sw t0, 32(sp)
|
|
li t0, 0x6120696c # li a
|
|
sw t0, 28(sp)
|
|
addi a0, sp, 28
|
|
li a1, 25
|
|
call _write_out
|
|
|
|
_advance(4) # Skip end.
|
|
_skip_spaces() # Read the possible new line at the end of the file.
|
|
end
|
|
|
|
# Finds the end of the line and returns its length in a0.
|
|
proc _read_line()
|
|
begin
|
|
mv t0, s1 # Local position in the source text.
|
|
|
|
.Lread_line_do:
|
|
lbu t1, (t0) # t1 = Current character.
|
|
beqz t1, .Lread_line_end # Exit the loop on the NUL character.
|
|
li t2, '\n'
|
|
beq t1, t2, .Lread_line_end # Exit the loop on the new line.
|
|
|
|
addi t0, t0, 1
|
|
j .Lread_line_do
|
|
|
|
.Lread_line_end:
|
|
sub a0, t0, s1 # Return the line length.
|
|
end
|
|
|
|
proc _compile()
|
|
begin
|
|
.Lcompile_do:
|
|
lbu t0, (s1) # t0 = Current character.
|
|
beqz t0, .Lcompile_end # Exit the loop on the NUL character.
|
|
|
|
_skip_indentation()
|
|
call _read_line
|
|
call _compile_line
|
|
|
|
j .Lcompile_do
|
|
.Lcompile_end:
|
|
end
|
|
|
|
# Returns the pointer to the current position in the source text in a0.
|
|
proc _current()
|
|
begin
|
|
mv a0, s1
|
|
end
|
|
|
|
# a0 is the number of bytes to advance in the source text.
|
|
proc _advance()
|
|
begin
|
|
add s1, s1, a0
|
|
end
|
|
|
|
# Entry point.
|
|
begin
|
|
# Read the source from the standard input.
|
|
la a0, source_code
|
|
la a1, SOURCE_BUFFER_SIZE # Buffer size.
|
|
lw a1, (a1)
|
|
call _read_file
|
|
|
|
la s1, source_code # s1 = Source code position.
|
|
call _compile
|
|
end.
|