39 lines
2.2 KiB
ArmAsm
39 lines
2.2 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 sw=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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.h"
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/ Performs addition on binary-coded decimals.
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bcdadd: .leafprologue
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.profilable
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lea 0x6666666(%rdi),%ecx
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xor %esi,%ecx
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lea (%rdi,%rsi),%eax
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add $0x6666666,%eax
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xor %eax,%ecx
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not %ecx
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and $0x11111110,%ecx
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mov %ecx,%edx
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shr $2,%edx
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shr $3,%ecx
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orl %edx,%ecx
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sub %ecx,%eax
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.leafepilogue
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.endfn bcdadd,globl
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