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https://github.com/jart/cosmopolitan.git
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68 lines
2.9 KiB
ArmAsm
68 lines
2.9 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.internal.h"
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#include "libc/bits/smmintrin.internal.h"
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#include "libc/nexgen32e/x86feature.h"
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// Rounds to nearest integer, away from zero.
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//
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// @param 𝑥 is double scalar in low half of %xmm0
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// @return double scalar in low half of %xmm0
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// @define round(𝑥) = copysign(trunc(fabs(𝑥)+.5),𝑥)
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// round(𝑥) = trunc(𝑥+copysign(.5,𝑥))
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round:
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#if !X86_NEED(SSE4_2)
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testb X86_HAVE(SSE4_2)+kCpuids(%rip)
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jz round$k8
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.text.antiquity
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round$k8:
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.leafprologue
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.profilable
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movapd %xmm0,%xmm1
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movsd D(%rip),%xmm2
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movsd C(%rip),%xmm3
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andpd %xmm2,%xmm1
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ucomisd %xmm1,%xmm3
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jbe 2f
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addsd A(%rip),%xmm1
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andnpd %xmm0,%xmm2
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movapd %xmm2,%xmm0
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cvttsd2siq %xmm1,%rax
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pxor %xmm1,%xmm1
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cvtsi2sdq %rax,%xmm1
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orpd %xmm1,%xmm0
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2: .leafepilogue
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.endfn round$k8,globl,hidden
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.previous
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.rodata.cst16
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C: .quad 0x4330000000000000,0
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D: .quad 0x7fffffffffffffff,0
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.previous
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#endif
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movapd %xmm0,%xmm1
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andpd B(%rip),%xmm0
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orpd A(%rip),%xmm0
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addsd %xmm1,%xmm0
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roundsd $_MM_FROUND_TO_ZERO,%xmm0,%xmm0
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ret
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.endfn round,globl
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.rodata.cst16
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A: .quad 0x3fdfffffffffffff,0
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B: .quad 0x8000000000000000,0
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