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https://github.com/CloverHackyColor/CloverBootloader.git
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79 lines
2.3 KiB
NASM
79 lines
2.3 KiB
NASM
;------------------------------------------------------------------------------
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;
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; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
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; SPDX-License-Identifier: BSD-2-Clause-Patent
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;
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; Module Name:
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;
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; CopyMem.nasm
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;
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; Abstract:
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;
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; CopyMem function
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;
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; Notes:
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;
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;------------------------------------------------------------------------------
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SECTION .text
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;------------------------------------------------------------------------------
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; VOID *
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; InternalMemCopyMem (
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; IN VOID *Destination,
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; IN VOID *Source,
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; IN UINTN Count
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; );
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;------------------------------------------------------------------------------
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global ASM_PFX(InternalMemCopyMem)
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ASM_PFX(InternalMemCopyMem):
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push esi
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push edi
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mov esi, [esp + 16] ; esi <- Source
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mov edi, [esp + 12] ; edi <- Destination
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mov edx, [esp + 20] ; edx <- Count
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lea eax, [esi + edx - 1] ; eax <- End of Source
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cmp esi, edi
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jae .0
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cmp eax, edi ; Overlapped?
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jae @CopyBackward ; Copy backward if overlapped
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.0:
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xor ecx, ecx
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sub ecx, edi
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and ecx, 15 ; ecx + edi aligns on 16-byte boundary
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jz .1
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cmp ecx, edx
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cmova ecx, edx
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sub edx, ecx ; edx <- remaining bytes to copy
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rep movsb
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.1:
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mov ecx, edx
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and edx, 15
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shr ecx, 4 ; ecx <- # of DQwords to copy
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jz @CopyBytes
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add esp, -16
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movdqu [esp], xmm0 ; save xmm0
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.2:
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movdqu xmm0, [esi] ; esi may not be 16-bytes aligned
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movntdq [edi], xmm0 ; edi should be 16-bytes aligned
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add esi, 16
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add edi, 16
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loop .2
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mfence
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movdqu xmm0, [esp] ; restore xmm0
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add esp, 16 ; stack cleanup
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jmp @CopyBytes
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@CopyBackward:
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mov esi, eax ; esi <- Last byte in Source
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lea edi, [edi + edx - 1] ; edi <- Last byte in Destination
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std
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@CopyBytes:
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mov ecx, edx
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rep movsb
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cld
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mov eax, [esp + 12] ; eax <- Destination as return value
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pop edi
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pop esi
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ret
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