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cosmopolitan/libc/intrin/bsr128.S

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Polish up repository and other revisions
2020-06-16 13:38:43 +00:00
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
Initial import
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│vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
Change license
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│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
Initial import
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│ │
Change license
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
Initial import
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╚─────────────────────────────────────────────────────────────────────────────*/
Remove more nonstandard stuff from cosmopolitan.h Fixes #61
2021-03-01 07:42:35 +00:00
#include "libc/macros.internal.h"
Initial import
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Get codebase completely working with LLVM 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.
2021-02-08 17:19:00 +00:00
// Returns binary logarithm of integer 𝑥.
//
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
2022-09-13 06:10:38 +00:00
// uint32 𝑥 _bsf(𝑥) tzcnt(𝑥) ffs(𝑥) bsr(𝑥) lzcnt(𝑥)
Get codebase completely working with LLVM 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.
2021-02-08 17:19:00 +00:00
// 0x00000000 wut 32 0 wut 32
// 0x00000001 0 0 1 0 31
// 0x80000001 0 0 1 31 0
// 0x80000000 31 31 32 31 0
// 0x00000010 4 4 5 4 27
// 0x08000010 4 4 5 27 4
// 0x08000000 27 27 28 27 4
// 0xffffffff 0 0 1 31 0
//
// @param rsi:rdi is 128-bit unsigned 𝑥 value
// @return eax number in range [0,128) or undef if 𝑥 is 0
// @see also treasure trove of nearly identical functions
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
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_bsr128:
.leafprologue
Initial import
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.profilable
bsr %rsi,%rax
jnz 2f
bsr %rdi,%rax
1: .leafepilogue
2: add $64,%eax
jmp 1b
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
2022-09-13 06:10:38 +00:00
.endfn _bsr128,globl
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