mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-02 13:03:28 +01:00
620401dca6
Signed-off-by: Sergey Isakov <isakov-sl@bk.ru>
73 lines
1.8 KiB
NASM
73 lines
1.8 KiB
NASM
;------------------------------------------------------------------------------
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; @file
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; Copyright (C) 2020, vit9696. All rights reserved.
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;
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; All rights reserved.
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;
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution. The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;------------------------------------------------------------------------------
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BITS 32
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DEFAULT REL
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SECTION .text
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;------------------------------------------------------------------------------
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; UINT64
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; EFIAPI
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; AsmAddRngJitter (
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; IN UINT64 Value
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; );
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;------------------------------------------------------------------------------
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align 8
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global ASM_PFX(AsmAddRngJitter)
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ASM_PFX(AsmAddRngJitter):
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; This assembly code corresponds to Hamming Weight implementation for targets
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; with fast multiplication.
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; REF: https://en.wikipedia.org/wiki/Hamming_weight#Efficient_implementation
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push esi
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mov edx, [esp+8]
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mov eax, [esp+12]
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mov ecx, edx
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shr ecx, 1
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mov esi, eax
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shr esi, 1
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and esi, 55555555h
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and ecx, 55555555h
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sub edx, ecx
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sbb eax, esi
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mov ecx, eax
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and ecx, 33333333h
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mov esi, edx
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and esi, 33333333h
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shr edx, 2
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shr eax, 2
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and eax, 33333333h
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add eax, ecx
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and edx, 33333333h
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add edx, esi
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mov ecx, eax
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shld ecx, edx, 1Ch
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mov esi, eax
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shr esi, 4
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add ecx, edx
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adc esi, eax
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and esi, 0F0F0F0Fh
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and ecx, 0F0F0F0Fh
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mov edx, 1010101h
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mov eax, ecx
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mul edx
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imul ecx, 1010101h
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add ecx, edx
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imul eax, esi, 1010101h
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add eax, ecx
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shr eax, 18h
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pop esi
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ret
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