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45 lines
2.6 KiB
ArmAsm
45 lines
2.6 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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│ 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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#include "libc/notice.inc"
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.text.startup
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.source __FILE__
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/ Intel Manual V.1 §10.2.3 - MXCSR Control and Status Register
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#define MXCSR_DE (1 << 1) /* Denormal Flag */
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#define MXCSR_DAZ (1 << 6) /* Denormals Are Zeros */
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#define MXCSR_DM (1 << 8) /* Denormal Operation Mask */
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#define MXCSR_FTZ (1 << 15) /* Flush to Zero */
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/ Initializes fast math.
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/
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/ “Seymour Cray didn't care that 81.0/3.0 did not give exactly
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/ 27.0 on the CDC 6000 class machines, and he was universally
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/ respected for making the fastest machines around.
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/ ──Linus Torvalds
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__fast_math:
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push %rbp
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mov %rsp,%rbp
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push %rax
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stmxcsr (%rsp)
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orl $MXCSR_FTZ+MXCSR_DAZ,(%rsp)
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ldmxcsr (%rsp)
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leave
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ret
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.endfn __fast_math,globl
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