audk/MdePkg/Library/BaseMemoryLibMmx/X64/SetMem.nasm

;------------------------------------------------------------------------------
;
; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
;   SetMem.nasm
;
; Abstract:
;
;   SetMem function
;
; Notes:
;
;------------------------------------------------------------------------------

    DEFAULT REL
    SECTION .text

;------------------------------------------------------------------------------
; VOID *
; EFIAPI
; InternalMemSetMem (
;   OUT     VOID                      *Buffer,
;   IN      UINTN                     Length,
;   IN      UINT8                     Value
;   );
;------------------------------------------------------------------------------
global ASM_PFX(InternalMemSetMem)
ASM_PFX(InternalMemSetMem):
    push    rdi
    mov     rax, r8
    mov     ah, al
    DB      0x48, 0xf, 0x6e, 0xc0         ; movd mm0, rax
    mov     r8, rcx
    mov     rdi, r8                     ; rdi <- Buffer
    mov     rcx, rdx
    and     edx, 7
    shr     rcx, 3
    jz      @SetBytes
    DB      0xf, 0x70, 0xC0, 0x0         ; pshufw mm0, mm0, 0h
.0:
    DB      0xf, 0xe7, 0x7              ; movntq [rdi], mm0
    add     rdi, 8
    loop    .0
    mfence
@SetBytes:
    mov     ecx, edx
    rep     stosb
    mov     rax, r8
    pop     rdi
    ret