43 lines
2.2 KiB
ArmAsm
43 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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/ Converts binary-coded-decimal to integer.
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/
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/ @param rdi is the string copied into a word
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bcd2i: .leafprologue
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.profilable
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test %rdi,%rdi
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je 2f
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mov $1,%ecx
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xor %eax,%eax
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1: mov %edi,%edx
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and $15,%edx
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imul %rcx,%rdx
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add %rdx,%rax
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add %rcx,%rcx
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lea (%rcx,%rcx,4),%rcx
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shr $4,%rdi
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jne 1b
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ret
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2: xor %eax,%eax
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.leafepilogue
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.endfn bcd2i,globl
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