diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/MdePkg/Library/BaseMemoryLibSse2/Ia32/IsZeroBuffer.nasm | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/MdePkg/Library/BaseMemoryLibSse2/Ia32/IsZeroBuffer.nasm')
| -rw-r--r-- | roms/edk2/MdePkg/Library/BaseMemoryLibSse2/Ia32/IsZeroBuffer.nasm | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/roms/edk2/MdePkg/Library/BaseMemoryLibSse2/Ia32/IsZeroBuffer.nasm b/roms/edk2/MdePkg/Library/BaseMemoryLibSse2/Ia32/IsZeroBuffer.nasm new file mode 100644 index 000000000..c3bfb7110 --- /dev/null +++ b/roms/edk2/MdePkg/Library/BaseMemoryLibSse2/Ia32/IsZeroBuffer.nasm @@ -0,0 +1,68 @@ +;------------------------------------------------------------------------------
+;
+; 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 edx, [esp + 12] ; edx <- Length
+ xor ecx, ecx ; ecx <- 0
+ sub ecx, edi
+ and ecx, 15 ; ecx + edi aligns on 16-byte boundary
+ jz @Is16BytesZero
+ cmp ecx, edx
+ cmova ecx, edx ; bytes before the 16-byte boundary
+ sub edx, ecx
+ xor eax, eax ; eax <- 0, also set ZF
+ repe scasb
+ jnz @ReturnFalse ; ZF=0 means non-zero element found
+@Is16BytesZero:
+ mov ecx, edx
+ and edx, 15
+ shr ecx, 4
+ jz @IsBytesZero
+.0:
+ pxor xmm0, xmm0 ; xmm0 <- 0
+ pcmpeqb xmm0, [edi] ; check zero for 16 bytes
+ pmovmskb eax, xmm0 ; eax <- compare results
+ cmp eax, 0xffff
+ jnz @ReturnFalse
+ add edi, 16
+ loop .0
+@IsBytesZero:
+ mov ecx, edx
+ xor eax, eax ; eax <- 0, also set ZF
+ repe scasb
+ jnz @ReturnFalse ; ZF=0 means non-zero element found
+ pop edi
+ mov eax, 1 ; return TRUE
+ ret
+@ReturnFalse:
+ pop edi
+ xor eax, eax
+ ret ; return FALSE
+
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