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60c414c346
The branch prediction hints is actually hurts performance in this case. The assembly implementation make two assumptions: 1. 'fabs (x) < 2^52' is unlikely and 2. 'x > 0.0' is unlike (if 1. is true). Since it a general floating point function, expected input is not bounded and then it is better to let the hardware handle the branches.
71 lines
2.0 KiB
ArmAsm
71 lines
2.0 KiB
ArmAsm
/* Round to int floating-point values. PowerPC32 version.
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Copyright (C) 2004-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* This has been coded in assembler because GCC makes such a mess of it
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when it's coded in C. */
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#include <sysdep.h>
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#include <math_ldbl_opt.h>
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.section .rodata.cst4,"aM",@progbits,4
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.align 2
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.LC0: /* 2**52 */
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.long 0x59800000
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.section ".text"
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ENTRY (__rint)
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#ifdef SHARED
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mflr r11
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cfi_register(lr,r11)
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SETUP_GOT_ACCESS(r9,got_label)
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addis r9,r9,.LC0-got_label@ha
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lfs fp13,.LC0-got_label@l(r9)
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mtlr r11
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cfi_same_value (lr)
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#else
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lis r9,.LC0@ha
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lfs fp13,.LC0@l(r9)
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#endif
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fabs fp0,fp1
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fsub fp12,fp13,fp13 /* generate 0.0 */
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fcmpu cr7,fp0,fp13 /* if (fabs(x) > TWO52) */
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fcmpu cr6,fp1,fp12 /* if (x > 0.0) */
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bnllr cr7
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bng cr6,.L4
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fadd fp1,fp1,fp13 /* x+= TWO52; */
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fsub fp1,fp1,fp13 /* x-= TWO52; */
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fabs fp1,fp1 /* if (x == 0.0) */
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blr /* x = 0.0; */
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.L4:
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bnllr cr6 /* if (x < 0.0) */
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fsub fp1,fp1,fp13 /* x-= TWO52; */
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fadd fp1,fp1,fp13 /* x+= TWO52; */
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fnabs fp1,fp1 /* if (x == 0.0) */
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blr /* x = -0.0; */
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END (__rint)
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weak_alias (__rint, rint)
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#ifdef NO_LONG_DOUBLE
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weak_alias (__rint, rintl)
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strong_alias (__rint, __rintl)
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#endif
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#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
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compat_symbol (libm, __rint, rintl, GLIBC_2_0)
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#endif
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