50 lines
2.5 KiB
ArmAsm
50 lines
2.5 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.h"
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/ Sets memory to zero w/ accompanying non-optimizing macro.
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/
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/ This is intended for security-conscious applications. This
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/ implementation also hoses every register the abi allows. A
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/ concomitant prototype (str.h) countermands compiler magic.
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/
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/ @param rdi is dest
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/ @param rsi is the number of bytes to set
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explicit_bzero:
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.leafprologue
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mov %rsi,%rcx
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xor %eax,%eax
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rep stosb
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xor %edx,%edx
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xor %edi,%edi
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xor %esi,%esi
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xor %r8,%r8
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xor %r9,%r9
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xor %r10,%r10
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xor %r11,%r11
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pxor %xmm0,%xmm0
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pxor %xmm1,%xmm1
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pxor %xmm2,%xmm2
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pxor %xmm3,%xmm3
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pxor %xmm4,%xmm4
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pxor %xmm5,%xmm5
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.leafepilogue
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.endfn explicit_bzero,globl
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.source __FILE__
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