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;------------------------------------------------------------------------------
;
; Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
; This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php.
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
; IsZeroBuffer.nasm
;
; Abstract:
;
; IsZeroBuffer function
;
; Notes:
;
;------------------------------------------------------------------------------
SECTION .text
;------------------------------------------------------------------------------
; BOOLEAN
; EFIAPI
; InternalMemIsZeroBuffer (
; IN CONST VOID *Buffer,
; IN UINTN Length
; );
;------------------------------------------------------------------------------
global ASM_PFX(InternalMemIsZeroBuffer)
ASM_PFX(InternalMemIsZeroBuffer):
push edi
mov edi, [esp + 8] ; edi <- Buffer
mov ecx, [esp + 12] ; ecx <- Length
mov edx, ecx ; edx <- ecx
shr ecx, 2 ; ecx <- number of dwords
and edx, 3 ; edx <- number of trailing bytes
xor eax, eax ; eax <- 0, also set ZF
repe scasd
jnz @ReturnFalse ; ZF=0 means non-zero element found
mov ecx, edx
repe scasb
jnz @ReturnFalse
pop edi
mov eax, 1 ; return TRUE
ret
@ReturnFalse:
pop edi
xor eax, eax
ret ; return FALSE
|
