2020-06-16 13:38:43 +00:00
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/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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2020-06-15 14:18:57 +00:00
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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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#include "libc/notice.inc"
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.text.startup
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2020-06-16 02:01:28 +00:00
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.source __FILE__
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2020-06-15 14:18:57 +00:00
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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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