74 lines
1.0 KiB
NASM
74 lines
1.0 KiB
NASM
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proc crash.crc32 _crc, _data, _len, _callback, _msglen
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.begin:
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mov ecx, [_len]
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test ecx, ecx
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jz .callback
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mov eax, [_crc]
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mov eax, [eax]
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mov esi, [_data]
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.head:
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mov ebx, [_data]
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and ebx, 3
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jz .body
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@@:
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dec ecx
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js .done
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movzx edx, al
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xor dl, byte[esi]
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add esi, 1
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shr eax, 8
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xor eax, [crash._.crc32_table + edx*4]
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dec ebx
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jnz @b
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.body:
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mov ebx, ecx
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and ecx, 15
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shr ebx, 4
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test ebx, ebx
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jz .tail
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@@:
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repeat 4
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mov edx, eax
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mov eax, [esi]
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add esi, 4
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xor eax, edx
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repeat 4
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movzx edx, al
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shr eax, 8
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xor eax, [crash._.crc32_table + edx*4]
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end repeat
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end repeat
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dec ebx
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jnz @b
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.tail:
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test ecx, ecx
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jz .done
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@@:
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movzx edx, al
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xor dl, byte[esi]
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add esi, 1
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shr eax, 8
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xor eax, [crash._.crc32_table + edx*4]
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dec ecx
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jnz @b
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.done:
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mov ecx, [_crc]
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mov [ecx], eax
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.callback:
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mov eax, [_callback]
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test eax, eax
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jz @f
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call eax
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mov [_len], eax
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test eax, eax
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jnz .begin
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@@:
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mov ecx, [_crc]
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mov eax, [ecx]
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xor eax, 0xffffffff
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bswap eax
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mov [ecx], eax
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ret
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endp
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