mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
e75ffde09e
You can now build Cosmopolitan with Clang:
make -j8 MODE=llvm
o/llvm/examples/hello.com
The assembler and linker code is now friendly to LLVM too.
So it's not needed to configure Clang to use binutils under
the hood. If you love LLVM then you can now use pure LLVM.
63 lines
2.8 KiB
ArmAsm
63 lines
2.8 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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#define BIAS 0x84
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// Encodes audio sample with µ-Law.
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//
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// This is both the highest quality and most widely supported
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// telephony codec, whose use was phased out in the 2000's in
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// favor of cost-saving GSM audio compression that was so bad
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// consumers were willing to pay more cash, for the privilege
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// of saving telcos even more money w/ text messaging. Mu Law
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// reduces PCM data to half its original size, by diminishing
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// audio bands not vocalized by human voice.
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//
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// @param %edi is pcm sample
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// @return %eax is uint8_t encoded sample
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mulaw: .leafprologue
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.profilable
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mov $BIAS,%eax
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xor %edx,%edx
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test %edi,%edi
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js 1f
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lea (%edi,%eax),%eax
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mov $0xFF,%dl
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jmp 2f
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1: sub %edi,%eax
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mov $0x7F,%dl
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2: mov %eax,%esi
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or $0xFF,%sil
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bsr %esi,%esi
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sub $7,%esi
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cmp $8,%esi
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jge 4f
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lea 3(%rdx),%ecx
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sar %cl,%eax
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and $0xF,%eax
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shl $4,%esi
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or %esi,%eax
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xor %edx,%eax
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3: .leafepilogue
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4: xor $0x7F,%dl
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mov %edx,%eax
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jmp 3b
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.endfn mulaw,globl
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.source __FILE__
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