56 lines
2.4 KiB
ArmAsm
56 lines
2.4 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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/ Compares strings w/ limit & no-clobber greg abi.
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/
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/ @param %rdi is first string
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/ @param %rsi is second string
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/ @param %rdx is max length
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/ @return <0, 0, or >0 depending on comparison
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/ @clob flags only
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/ @asyncsignalsafe
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tinystrncmp:
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.leafprologue
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push %rbx
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push %rcx
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xor %eax,%eax
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xor %ebx,%ebx
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xor %ecx,%ecx
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test %edx,%edx
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jz 2f
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cmp %rdi,%rsi
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je 2f
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0: cmp %edx,%ecx
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jae 1f
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movzbl (%rdi,%rcx,1),%eax
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movzbl (%rsi,%rcx,1),%ebx
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test %al,%al
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jz 1f
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cmp %bl,%al
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jne 1f
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inc %ecx
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jmp 0b
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1: sub %ebx,%eax
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2: pop %rcx
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pop %rbx
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.leafepilogue
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.endfn tinystrncmp,globl
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.source __FILE__
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