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113 lines
1.9 KiB
ArmAsm
113 lines
1.9 KiB
ArmAsm
/* Copyright (c) Mark Harmstone 2020
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*
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* This file is part of WinBtrfs.
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*
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* WinBtrfs is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public Licence as published by
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* the Free Software Foundation, either version 3 of the Licence, or
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* (at your option) any later version.
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*
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* WinBtrfs is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public Licence for more details.
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*
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* You should have received a copy of the GNU Lesser General Public Licence
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* along with WinBtrfs. If not, see <http://www.gnu.org/licenses/>. */
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#include <asm.inc>
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EXTERN crctable:QWORD
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.code64
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/* uint32_t __stdcall calc_crc32c_sw(uint32_t seed, uint8_t* msg, uint32_t msglen); */
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PUBLIC calc_crc32c_sw
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calc_crc32c_sw:
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/* rax = crc / seed
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* rdx = buf
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* r8 = len
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* rcx = tmp
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* r10 = tmp2 */
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mov rax, rcx
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crcloop:
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test r8, r8
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jz crcend
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mov rcx, rax
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shr rcx, 8
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mov r10b, byte ptr [rdx]
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xor al, r10b
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and rax, 255
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shl rax, 2
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mov r10, offset crctable
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mov eax, dword ptr [r10 + rax]
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xor rax, rcx
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inc rdx
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dec r8
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jmp crcloop
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crcend:
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ret
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/****************************************************/
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/* uint32_t __stdcall calc_crc32c_hw(uint32_t seed, uint8_t* msg, uint32_t msglen); */
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PUBLIC calc_crc32c_hw
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calc_crc32c_hw:
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/* rax = crc / seed
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* rdx = buf
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* r8 = len */
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mov rax, rcx
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crchw_loop:
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cmp r8, 8
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jl crchw_stragglers
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crc32 rax, qword ptr [rdx]
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add rdx, 8
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sub r8, 8
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jmp crchw_loop
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crchw_stragglers:
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cmp r8, 4
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jl crchw_stragglers2
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crc32 eax, dword ptr [rdx]
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add rdx, 4
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sub r8, 4
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crchw_stragglers2:
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cmp r8, 2
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jl crchw_stragglers3
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crc32 eax, word ptr [rdx]
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add rdx, 2
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sub r8, 2
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crchw_stragglers3:
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test r8, r8
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jz crchw_end
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crc32 eax, byte ptr [rdx]
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inc rdx
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dec r8
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jmp crchw_stragglers3
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crchw_end:
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ret
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END
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