mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-18 15:27:48 +01:00
50 lines
1.5 KiB
NASM
50 lines
1.5 KiB
NASM
;------------------------------------------------------------------------------
|
|
;
|
|
; Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
|
|
; SPDX-License-Identifier: BSD-2-Clause-Patent
|
|
;
|
|
; 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
|
|
|