153 lines
2.6 KiB
NASM
153 lines
2.6 KiB
NASM
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mem_copy:
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; todo(perf): Copy multiple bytes at once
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.prolog:
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push esi
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sub esp, 64
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mov esi, esp
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; Save registers
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mov [esi + (64 - 4)], eax
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mov [esi + (64 - 8)], ebx
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mov [esi + (64 - 12)], ecx
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mov [esi + (64 - 16)], edx
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mov [esi + (64 - 20)], edi
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.body:
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mov edx, [ebp - 4] ; Destination
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mov edi, [ebp - 8] ; Source
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xor eax, eax ; Current Byte Offset
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.body.copy_loop:
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mov ebx, edi
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add ebx, eax
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mov cl, [ebx]
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mov ebx, edx
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add ebx, eax
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mov [ebx], cl
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inc eax
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cmp eax, [ebp - 12]
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jb .body.copy_loop
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.epilog:
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; Restore registers
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mov eax, [esi + (64 - 4)]
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mov ebx, [esi + (64 - 8)]
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mov ecx, [esi + (64 - 12)]
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mov edx, [esi + (64 - 16)]
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mov edi, [esi + (64 - 20)]
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add esp, 64
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pop esi
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ret
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; Furthest from EBP
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; 3. Length of block 1 and block 2
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; 2. Block 2
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; 1. Block 1
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; Nearest to EBP
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mem_equal:
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.prolog:
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push esi
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sub esp, 32
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mov esi, esp
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; Save registers
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mov [esi + (32 - 4)], ebx
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mov [esi + (32 - 8)], ecx
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mov [esi + (32 - 12)], edx
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mov [esi + (32 - 16)], edi
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.body:
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mov edx, [ebp - 4] ; Block 1
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mov edi, [ebp - 8] ; Block 2
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xor eax, eax ; Current Byte Offset
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.body.compare_loop:
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mov ebx, edx
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add ebx, eax
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mov dl, [ebx]
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mov ebx, edi
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add ebx, eax
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mov dh, [ebx]
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inc eax
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cmp dl, dh
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je .body.compare_loop.condition
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; On NOT equal
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xor eax, eax
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jmp .epilog
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.body.compare_loop.condition:
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inc eax
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cmp eax, [ebp - 12]
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jb .body.compare_loop
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mov eax, 1
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.epilog:
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; Restore registers
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mov ebx, [esi + (32 - 4)]
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mov ecx, [esi + (32 - 8)]
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mov edx, [esi + (32 - 12)]
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mov edi, [esi + (32 - 16)]
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add esp, 32
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pop esi
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ret
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; ebp - 4: Area Pointer
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; ebp - 8: Length of Area
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; ebp - 12: Byte Value to set
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mem_set:
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.prolog:
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push esi
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sub esp, 64
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mov esi, esp
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; Save registers
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mov [esi + (64 - 4)], eax
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mov [esi + (64 - 8)], ebx
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mov [esi + (64 - 12)], ecx
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mov [esi + (64 - 16)], edx
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mov [esi + (64 - 20)], edi
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.body:
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mov ebx, [ebp - 4]
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mov dl, [ebp - 12]
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; Make EDI the Last Byte Pointer
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mov edi, [ebp - 4]
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add edi, [ebp - 8]
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.body.setter_loop:
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cmp ebx, edi
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jae .epilog
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mov [ebx], dl
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inc ebx
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jb .body.setter_loop
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.epilog:
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; Restore registers
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mov eax, [esi + (64 - 4)]
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mov ebx, [esi + (64 - 8)]
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mov ecx, [esi + (64 - 12)]
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mov edx, [esi + (64 - 16)]
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mov edi, [esi + (64 - 20)]
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add esp, 64
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pop esi
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ret
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