908 lines
15 KiB
ArmAsm
908 lines
15 KiB
ArmAsm
# s1 - Contains the current position in the source text.
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.global _start # Program entry point.
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.section .rodata
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.equ SOURCE_BUFFER_SIZE, 2048
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asm_begin: .ascii ".text\n.global _start\n_start:\naddi sp, sp, -64\nsw ra, 60(sp)\nsw s0, 56(sp)\naddi s0, sp, 64\n"
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.equ ASM_BEGIN_SIZE, . - asm_begin
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asm_end: .ascii "addi a0, zero, 0\naddi a7, zero, 93\necall\nlw ra, 60(sp)\nlw s0, 56(sp)\naddi sp, sp, 64\nret\n"
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.equ ASM_END_SIZE, . - asm_end
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asm_program: .ascii ".bss\n"
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.equ ASM_PROGRAM_SIZE, . - asm_program
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asm_type: .ascii ".type "
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.equ ASM_TYPE_SIZE, . - asm_type
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asm_object: .ascii ", @object\n"
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.equ ASM_OBJECT_SIZE, . - asm_object
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asm_size: .ascii ".size "
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.equ ASM_SIZE_SIZE, . - asm_size
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asm_zero: .ascii ".zero "
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.equ ASM_ZERO_SIZE, . - asm_zero
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asm_global: .ascii ".global "
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.equ ASM_GLOBAL_SIZE, . - asm_global
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token_begin: .string "begin"
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token_end: .string "end"
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token_import: .string "import"
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token_open_paren: .string "("
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token_close_paren: .string ")"
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token_open_square: .string "["
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token_assign: .string ":="
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token_var: .string "var"
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token_comma: .string ","
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space: .ascii " "
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comma: .ascii ","
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new_line: .ascii "\n"
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colon: .ascii ":"
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digit_zero: .ascii "0"
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instruction_la: .ascii "la"
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instruction_call: .ascii "call"
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instruction_addi: .ascii "addi"
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instruction_li: .ascii "li"
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instruction_sw: .ascii "sw"
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instruction_lw: .ascii "lw"
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register_a0: .ascii "a0"
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register_sp: .ascii "sp"
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register_a: .ascii "a"
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.section .bss
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.global source_code
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.type source_code, @object
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.size source_code, SOURCE_BUFFER_SIZE
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source_code: .zero SOURCE_BUFFER_SIZE
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.section .text
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.type _skip_spaces, @function
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_skip_spaces:
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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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addi s1, s1, 1
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j .Lspace_loop_do
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.Lspace_loop_end:
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ret
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# Compares two string, which of one has a length, the other one is null-terminated.
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#
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# a0 - The address of the token string.
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# a1 - The length of the string in a0.
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# a2 - The address of the null-terminated string.
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#
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# If the strings match sets a0 to 0, otherwise sets it to 1.
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.type _token_compare, @function
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_token_compare:
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addi t0, a0, 0
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addi t1, a1, 0
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addi t2, a2, 0
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.Ltoken_compare_loop:
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lbu t3, (t2)
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# Will only be 0 if the current character in the null terminated string is \0 and the remaining length of the
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# another string is 0.
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or t4, t3, t1
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beqz t4, .Ltoken_compare_equal
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beqz t1, .Ltoken_compare_not_equal
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beqz t3, .Ltoken_compare_not_equal
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lbu t4, (t0)
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bne t3, t4, .Ltoken_compare_not_equal
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addi t0, t0, 1
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addi t1, t1, -1
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addi t2, t2, 1
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j .Ltoken_compare_loop
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.Ltoken_compare_not_equal:
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li a0, 1
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j .Ltoken_compare_end
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.Ltoken_compare_equal:
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li a0, 0
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.Ltoken_compare_end:
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ret
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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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.type _read_token, @function
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_read_token:
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# Prologue.
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addi sp, sp, -16
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sw ra, 12(sp)
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sw s0, 8(sp)
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addi s0, sp, 16
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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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# Epilogue.
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lw ra, 12(sp)
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lw s0, 8(sp)
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addi sp, sp, 16
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ret
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# Generate entry point symbol.
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.type _compile_begin, @function
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_compile_begin:
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# Prologue.
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addi sp, sp, -8
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sw ra, 4(sp)
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sw s0, 0(sp)
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addi s0, sp, 8
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# Write initial assembler.
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la a0, asm_begin
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addi a1, zero, ASM_BEGIN_SIZE
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call write_out
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addi s1, s1, 5
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# Epilogue.
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lw ra, 4(sp)
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lw s0, 0(sp)
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addi sp, sp, 8
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ret
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# Generate program termination code.
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.type _compile_end, @function
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_compile_end:
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# Prologue.
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addi sp, sp, -8
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sw ra, 4(sp)
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sw s0, 0(sp)
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addi s0, sp, 8
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# Write closing assembler.
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la a0, asm_end
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addi a1, zero, ASM_END_SIZE
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call write_out
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addi s1, s1, 3
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# Epilogue.
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lw ra, 4(sp)
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lw s0, 0(sp)
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addi sp, sp, 8
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ret
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# Ignores the import.
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.type _compile_import, @function
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_compile_import:
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# Prologue.
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addi sp, sp, -8
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sw ra, 4(sp)
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sw s0, 0(sp)
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addi s0, sp, 8
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addi s1, s1, 6
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call _skip_spaces
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call _read_token
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add s1, s1, a0 # Skip the imported module name.
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# Epilogue.
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lw ra, 4(sp)
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lw s0, 0(sp)
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addi sp, sp, 8
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ret
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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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.type _compile_call, @function
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_compile_call:
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# Prologue.
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addi sp, sp, -32
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sw ra, 28(sp)
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sw s0, 24(sp)
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addi s0, sp, 32
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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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call _skip_spaces
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call _read_token
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addi a1, a0, 0
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addi a0, s1, 0
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la a2, token_close_paren
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call _token_compare
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beqz a0, .Lcompile_call_complete
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.Lcompile_call_argument:
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call _build_expression
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la a0, instruction_sw
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li a1, 2
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call write_out
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la a0, space
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li a1, 1
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call write_out
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la a0, register_a0
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li a1, 2
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call write_out
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la a0, comma
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li a1, 1
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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, 52
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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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la a0, token_open_paren
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li a1, 1
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call write_out
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la a0, register_sp
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li a1, 2
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call write_out
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la a0, token_close_paren
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li a1, 1
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call write_out
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la a0, new_line
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li a1, 1
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call write_out
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call _skip_spaces
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call _read_token
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addi a1, a0, 0
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addi a0, s1, 0
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la a2, token_comma
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call _token_compare
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/* DEBUG. Write the current token to stderr.
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addi a0, zero, STDERR
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addi a1, s1, 0
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li a2, 4 #(sp)
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addi a7, zero, SYS_WRITE
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ecall
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addi a0, zero, STDERR
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la a1, token_open_square
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li a2, 1
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addi a7, zero, SYS_WRITE
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ecall
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DEBUG. End */
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bnez a0, .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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addi s1, s1, 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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la a0, instruction_lw
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li a1, 2
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call write_out
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la a0, space
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li a1, 1
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call write_out
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la a0, register_a
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li a1, 1
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call write_out
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lw t0, 12(sp)
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addi t0, t0, '0'
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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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la a0, comma
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li a1, 1
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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, 52
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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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la a0, token_open_paren
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li a1, 1
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call write_out
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la a0, register_sp
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li a1, 2
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call write_out
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la a0, token_close_paren
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li a1, 1
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call write_out
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la a0, new_line
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li a1, 1
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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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la a0, instruction_call
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li a1, 4
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call write_out
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la a0, space
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li a1, 1
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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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la a0, new_line
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li a1, 1
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call write_out
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call _skip_spaces
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addi s1, s1, 1 # Skip the close paren.
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# Epilogue.
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lw ra, 28(sp)
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lw s0, 24(sp)
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addi sp, sp, 32
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ret
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.type _compile, @function
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compile:
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# Prologue.
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addi sp, sp, -16
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sw ra, 12(sp)
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sw s0, 8(sp)
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addi s0, sp, 16
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# Write .bss section header for global variables.
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la a0, asm_program
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addi a1, zero, ASM_PROGRAM_SIZE
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call write_out
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call _skip_spaces
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addi s1, s1, 7 # Skip "program" keyword.
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.Lcharacter_loop_do:
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call _skip_spaces
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lbu t0, (s1) # t0 = Current character.
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beqz t0, .Lcharacter_loop_end
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call _read_token
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sw a0, 4(sp) # Save the token length on the stack.
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beqz a0, .Lcharacter_loop_end # No token read, there is unrecognized input.
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lw a0, 4(sp)
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call _handle_token
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j .Lcharacter_loop_do
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.Lcharacter_loop_end:
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# Epilogue.
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lw ra, 12(sp)
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lw s0, 8(sp)
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addi sp, sp, 16
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ret
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# Evalutes an expression and saves the result in a0.
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.type _build_expression, @function
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_build_expression:
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# Prologue.
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addi sp, sp, -16
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sw ra, 12(sp)
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sw s0, 8(sp)
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addi s0, sp, 16
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call _skip_spaces
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call _read_token
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sw s1, 4(sp)
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sw a0, 0(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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la a0, instruction_la
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li a1, 2
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call write_out
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la a0, space
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li a1, 1
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call write_out
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la a0, register_a0
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li a1, 2
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call write_out
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la a0, comma
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li a1, 1
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call write_out
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lw a0, 4(sp)
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lw a1, 0(sp)
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call write_out
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la a0, new_line
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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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la a0, instruction_li
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li a1, 2
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call write_out
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la a0, space
|
|
li a1, 1
|
|
call write_out
|
|
|
|
la a0, register_a0
|
|
li a1, 2
|
|
call write_out
|
|
|
|
la a0, comma
|
|
li a1, 1
|
|
call write_out
|
|
|
|
lw a0, 4(sp)
|
|
lw a1, 0(sp)
|
|
call write_out
|
|
|
|
la a0, new_line
|
|
li a1, 1
|
|
call write_out
|
|
|
|
j .Lbuild_expression_end
|
|
|
|
.Lbuild_expression_end:
|
|
lw a0, 0(sp)
|
|
add s1, s1, a0
|
|
|
|
# Epilogue.
|
|
lw ra, 12(sp)
|
|
lw s0, 8(sp)
|
|
addi sp, sp, 16
|
|
ret
|
|
|
|
# Compiles a statement beginning with an identifier.
|
|
.type _compile_identifier, @function
|
|
_compile_identifier:
|
|
# Prologue.
|
|
addi sp, sp, -32
|
|
sw ra, 28(sp)
|
|
sw s0, 24(sp)
|
|
addi s0, sp, 32
|
|
|
|
# Save the pointer to the identifier and its length on the stack.
|
|
sw a0, 20(sp)
|
|
sw a1, 16(sp)
|
|
|
|
add s1, s1, a1
|
|
call _skip_spaces
|
|
call _read_token
|
|
|
|
# Save the pointer and the length of the token following the identifier.
|
|
sw s1, 12(sp)
|
|
sw a0, 8(sp)
|
|
|
|
add s1, s1, a0 # Skip that token.
|
|
call _skip_spaces
|
|
|
|
lw a0, 12(sp)
|
|
lw a1, 8(sp)
|
|
la a2, token_assign
|
|
call _token_compare
|
|
beqz a0, .Lcompile_identifier_assign
|
|
|
|
lw a0, 12(sp)
|
|
lw a1, 8(sp)
|
|
la a2, token_open_paren
|
|
call _token_compare
|
|
beqz a0, .Lcompile_identifier_call
|
|
|
|
j .Lcompile_identifier_end
|
|
|
|
.Lcompile_identifier_call:
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call _compile_call
|
|
|
|
j .Lcompile_identifier_end
|
|
|
|
.Lcompile_identifier_assign:
|
|
call _build_expression
|
|
|
|
la a0, instruction_addi
|
|
li a1, 4
|
|
call write_out
|
|
|
|
la a0, space
|
|
li a1, 1
|
|
call write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call write_out
|
|
|
|
la a0, comma
|
|
li a1, 1
|
|
call write_out
|
|
|
|
la a0, register_a0
|
|
li a1, 2
|
|
call write_out
|
|
|
|
la a0, comma
|
|
li a1, 1
|
|
call write_out
|
|
|
|
la a0, digit_zero
|
|
li a1, 1
|
|
call write_out
|
|
|
|
la a0, new_line
|
|
li a1, 1
|
|
call write_out
|
|
|
|
j .Lcompile_identifier_end
|
|
|
|
.Lcompile_identifier_end:
|
|
# Epilogue.
|
|
lw ra, 28(sp)
|
|
lw s0, 24(sp)
|
|
addi sp, sp, 32
|
|
ret
|
|
|
|
.type _compile_var, @function
|
|
_compile_var:
|
|
# Prologue.
|
|
addi sp, sp, -32
|
|
sw ra, 28(sp)
|
|
sw s0, 24(sp)
|
|
addi s0, sp, 32
|
|
|
|
# Variable name.
|
|
addi s1, s1, 3
|
|
call _skip_spaces
|
|
call _read_token
|
|
sw s1, 20(sp)
|
|
sw a0, 16(sp)
|
|
add s1, s1, a0
|
|
|
|
# Skip the colon.
|
|
call _skip_spaces
|
|
call _read_token
|
|
add s1, s1, a0
|
|
|
|
call _skip_spaces
|
|
call _read_token
|
|
sw a0, 12(sp)
|
|
|
|
addi a0, s1, 0
|
|
lw a1, 12(sp)
|
|
la a2, token_open_square
|
|
call _token_compare
|
|
beqz a0, .Lcompile_var_array
|
|
|
|
j .Lcompile_var_end
|
|
|
|
.Lcompile_var_array:
|
|
call _skip_spaces
|
|
add s1, s1, 1 # Skip the opening square bracket.
|
|
|
|
call _skip_spaces
|
|
call _read_token
|
|
sw a0, 8(sp)
|
|
|
|
la a0, asm_type
|
|
li a1, ASM_TYPE_SIZE
|
|
call write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call write_out
|
|
|
|
la a0, asm_object
|
|
li a1, ASM_OBJECT_SIZE
|
|
call write_out
|
|
|
|
la a0, asm_size
|
|
li a1, ASM_SIZE_SIZE
|
|
call write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call write_out
|
|
|
|
la a0, comma
|
|
li a1, 1
|
|
call write_out
|
|
|
|
addi a0, s1, 0
|
|
lw a1, 8(sp)
|
|
call write_out
|
|
|
|
la a0, new_line
|
|
li a1, 1
|
|
call write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call write_out
|
|
|
|
la a0, colon
|
|
li a1, 1
|
|
call write_out
|
|
|
|
la a0, asm_zero
|
|
li a1, ASM_ZERO_SIZE
|
|
call write_out
|
|
|
|
addi a0, s1, 0
|
|
lw a1, 8(sp)
|
|
call write_out
|
|
|
|
la a0, new_line
|
|
li a1, 1
|
|
call write_out
|
|
|
|
la a0, asm_global
|
|
li a1, ASM_GLOBAL_SIZE
|
|
call write_out
|
|
|
|
lw a0, 20(sp)
|
|
lw a1, 16(sp)
|
|
call write_out
|
|
|
|
la a0, new_line
|
|
li a1, 1
|
|
call write_out
|
|
|
|
lw a0, 8(sp)
|
|
add s1, s1, a0
|
|
|
|
call _skip_spaces
|
|
add s1, s1, 1 # Skip the closing square bracket.
|
|
|
|
call _skip_spaces
|
|
call _read_token
|
|
|
|
sw a0, 12(sp)
|
|
j .Lcompile_var_end
|
|
|
|
.Lcompile_var_end:
|
|
lw a0, 12(sp)
|
|
add s1, s1, a0
|
|
|
|
# Epilogue.
|
|
lw ra, 28(sp)
|
|
lw s0, 24(sp)
|
|
addi sp, sp, 32
|
|
ret
|
|
|
|
.type _handle_token, @function
|
|
_handle_token:
|
|
# Prologue.
|
|
addi sp, sp, -32
|
|
sw ra, 28(sp)
|
|
sw s0, 24(sp)
|
|
addi s0, sp, 32
|
|
|
|
sw a0, 20(sp)
|
|
|
|
# Detect what token has been read.
|
|
addi a0, s1, 0
|
|
lw a1, 20(sp)
|
|
la a2, token_begin
|
|
call _token_compare
|
|
beqz a0, .Lhandle_token_begin
|
|
|
|
addi a0, s1, 0
|
|
lw a1, 20(sp)
|
|
la a2, token_end
|
|
call _token_compare
|
|
beqz a0, .Lhandle_token_end
|
|
|
|
addi a0, s1, 0
|
|
lw a1, 20(sp)
|
|
la a2, token_import
|
|
call _token_compare
|
|
beqz a0, .Lhandle_token_import
|
|
|
|
addi a0, s1, 0
|
|
lw a1, 20(sp)
|
|
la a2, token_var
|
|
call _token_compare
|
|
beqz a0, .Lhandle_token_var
|
|
|
|
# If the first symbol in the token is a character, assume an identifier.
|
|
addi a0, s1, 0
|
|
lb a0, (a0)
|
|
call is_alpha
|
|
bnez a0, .Lhandle_token_identifier
|
|
|
|
# Ignore the unknown token.
|
|
lw t0, 20(sp)
|
|
add s1, s1, t0
|
|
j .Lhandle_token_return
|
|
|
|
.Lhandle_token_begin:
|
|
call _compile_begin
|
|
j .Lhandle_token_return
|
|
|
|
.Lhandle_token_end:
|
|
call _compile_end
|
|
j .Lhandle_token_return
|
|
|
|
.Lhandle_token_import:
|
|
call _compile_import
|
|
j .Lhandle_token_return
|
|
|
|
.Lhandle_token_var:
|
|
call _compile_var
|
|
j .Lhandle_token_return
|
|
|
|
.Lhandle_token_identifier:
|
|
addi a0, s1, 0
|
|
lw a1, 20(sp)
|
|
call _compile_identifier
|
|
j .Lhandle_token_return
|
|
|
|
.Lhandle_token_return:
|
|
# Epilogue.
|
|
lw ra, 28(sp)
|
|
lw s0, 24(sp)
|
|
addi sp, sp, 32
|
|
ret
|
|
|
|
_start:
|
|
# Read the source from the standard input.
|
|
la a0, source_code
|
|
li a1, SOURCE_BUFFER_SIZE # Buffer size.
|
|
call read_file
|
|
|
|
la s1, source_code # s1 = Source code position.
|
|
call compile
|
|
|
|
# Call exit.
|
|
li a0, 0 # Use 0 return code.
|
|
call exit
|