64 lines
1.2 KiB
NASM
64 lines
1.2 KiB
NASM
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; integer routines
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; convert ASCII string into an integer
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; thanks to lua for helping with this :3
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; inputs:
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; r0: pointer to null-terminated string
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; r1: radix (i.e. 10 for decimal, 16 for hexadecimal)
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; outputs:
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; r0: integer
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string_to_int:
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push r2
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push r3
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mov r3, 0
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string_to_int_loop:
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movz.8 r2, [r0]
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inc r0
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cmp r2, 0
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ifz jmp string_to_int_end
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; if (digit >= '0' && digit <= '9') {
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; digit -= '0';
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; } else if (digit >= 'A' && digit <= 'Z') {
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; digit -= 'A' - 10
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; } else if (digit >= 'a' && digit <= 'z') {
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; digit -= 'a' - 10
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; } else {
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; continue;
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; }
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cmp r2, '0'
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iflt jmp string_to_int_loop_2
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cmp r2, '9'
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ifgt jmp string_to_int_loop_2
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sub r2, '0'
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jmp string_to_int_loop_end
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string_to_int_loop_2:
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cmp r2, 'A'
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iflt jmp string_to_int_loop_3
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cmp r2, 'Z'
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ifgt jmp string_to_int_loop_3
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sub r2, 0x37 ; 'A' - 10
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jmp string_to_int_loop_end
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string_to_int_loop_3:
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cmp r2, 'a'
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iflt jmp string_to_int_loop
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cmp r2, 'z'
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ifgt jmp string_to_int_loop
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sub r2, 0x57 ; 'a' - 10
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string_to_int_loop_end:
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mul r3, r1
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add r3, r2
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jmp string_to_int_loop
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string_to_int_end:
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mov r0, r3
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pop r3
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pop r2
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ret
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