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Diffstat (limited to 'Core/CPU/x64/x64AsmLib/MemCpy.asm')
| -rw-r--r-- | Core/CPU/x64/x64AsmLib/MemCpy.asm | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/Core/CPU/x64/x64AsmLib/MemCpy.asm b/Core/CPU/x64/x64AsmLib/MemCpy.asm new file mode 100644 index 0000000..a671ec8 --- /dev/null +++ b/Core/CPU/x64/x64AsmLib/MemCpy.asm @@ -0,0 +1,178 @@ +;************************************************************************* +;************************************************************************* +;** ** +;** (C)Copyright 1985-2009, American Megatrends, Inc. ** +;** ** +;** All Rights Reserved. ** +;** ** +;** 5555 Oakbrook Parkway, Suite 200, Norcross, GA 30093 ** +;** ** +;** Phone: (770)-246-8600 ** +;** ** +;************************************************************************* +;************************************************************************* + +;************************************************************************* +; $Header: /Alaska/SOURCE/Core/Modules/x64Core/x64AsmLib/MemCpy.asm 2 3/09/11 1:58p Felixp $ +; +; $Revision: 2 $ +; +; $Date: 3/09/11 1:58p $ +;************************************************************************* +; Revision History +; ---------------- +; $Log: /Alaska/SOURCE/Core/Modules/x64Core/x64AsmLib/MemCpy.asm $ +; +; 2 3/09/11 1:58p Felixp +; MemCpy is updated to copy 8 bytes at a time (used to be 4) +; +; 1 10/01/10 5:07p Felixp +; +; 1 8/24/06 12:57p Felixp +; +;************************************************************************* +;<AMI_FHDR_START> +; +; Name: +; +; Description: +; +;<AMI_FHDR_END> +;************************************************************************* +.code + +;************************************************************************* +;<AMI_PHDR_START> +; +; Name: MemCpy +; +; Description: +; VOID MemCpy(OUT VOID *pDestination, IN VOID *pSource, IN UINTN Count) +; copies Count bytes of memory from Source to Destination. +; +; Input: +; OUT VOID *pDestination +; Memory address where data shall be copied. User is responsible for +; allocating the necessary memory resources. +; +; IN VOID *pSource +; Memory address from where data shall be copied. +; +; IN UINTN Count +; Number of bytes to copy from pSource. +; +; Output: +; VOID. +; +; Modified: +; +; Referrals: +; +; Notes: +; This function checks for overlapping of source and destination and +; selects copy direction that prevents memory corruption. +; +;<AMI_PHDR_END> +;************************************************************************* +public memcpy +memcpy: +MemCpy proc + push rdi + push rsi + push rbx + pushf + mov rsi, rdx ; pSource + mov rdi, rcx ; pDestination + mov rcx, r8 ; Count + mov dl, 0 + ; if pSource > pDestination CopyForward + mov rax, rsi + sub rax, rdi ; rax = pSource-pDestination + jnb CopyForward; if pSource-pDestination > 0 CopyForward + ; if pSource+Count < pDestination then CopyForward + lea rbx, [rsi+rcx] ; rbx = pSource + Count + neg rax ; rax = pDestination - pSource + cmp rbx, rdi + jb CopyForward ; if (pSource + Count < pDestination ) CopyForward + ; Copy Backward + mov rsi, rbx; rsi = pSource + Count + lea rdi, [rdi+rcx]; rdi = pDestination + Count + mov dl, 1; Flag to indicate that we are copying backward + std; set direction flag to copy backward +CopyForward: + cmp rcx, 8 ; if (Counter<8) copy byte by byte + jb m8 + cmp rax, 8 ; if (pDestination - pSource < 8) copy byte by byte + jb m8 + ; if pSource and pDestination are not 8 byte aligned + ; Calculate 8-(Buffer%8), which is a number of bytes we have to copy to align the buffer + ; if this number if the same for source and destinations + ; copy several bytes to align them + ; otherwise proceed to QWORD copy + mov rax, rsi + mov rbx, rdi + and rax, 7 + and rbx, 7 + test dl, dl + jz skip1 + dec rsi + dec rdi +skip1: + cmp rax, rbx + jne m64 + test rax, rax + jz m64 + test dl, dl + jnz skip_nz1 + neg rax + add rax, 8 +skip_nz1: + xchg rax, rcx + sub rax, rcx + rep movsb + mov rcx, rax +m64: + test dl, dl + jz skip2 + sub rsi, 7 + sub rdi, 7 +skip2: + mov rax, rcx + shr rcx, 3 + rep movsq + and rax, 7 + jz MemCpuEnd + test dl, dl + jz skip3 + add rsi, 8 + add rdi, 8 +skip3: + mov rcx, rax +m8: + test dl, dl + jz skip4 + dec rsi + dec rdi +skip4: + rep movsb +MemCpuEnd: + popf + pop rbx + pop rsi + pop rdi + ret +MemCpy endp + +END +;************************************************************************* +;************************************************************************* +;** ** +;** (C)Copyright 1985-2009, American Megatrends, Inc. ** +;** ** +;** All Rights Reserved. ** +;** ** +;** 5555 Oakbrook Parkway, Suite 200, Norcross, GA 30093 ** +;** ** +;** Phone: (770)-246-8600 ** +;** ** +;************************************************************************* |