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96 lines
2.8 KiB
ArmAsm
96 lines
2.8 KiB
ArmAsm
/* round function. 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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#include <sysdep.h>
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#include <math_ldbl_opt.h>
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.section .rodata.cst8,"aM",@progbits,8
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.align 2
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.LC0: /* 2**52 */
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.long 0x59800000
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.LC1: /* 0.5 */
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.long 0x3f000000
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/* double [fp1] round (double x [fp1])
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IEEE 1003.1 round function. IEEE specifies "round to the nearest
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integer value, rounding halfway cases away from zero, regardless of
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the current rounding mode." However PowerPC Architecture defines
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"Round to Nearest" as "Choose the best approximation. In case of a
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tie, choose the one that is even (least significant bit o).".
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So we can't use the PowerPC "Round to Nearest" mode. Instead we set
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"Round toward Zero" mode and round by adding +-0.5 before rounding
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to the integer value. */
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.section ".text"
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ENTRY (__round)
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mffs fp11 /* Save current FPU rounding mode. */
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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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addi r9,r9,.LC0-got_label@l
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mtlr r11
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cfi_same_value (lr)
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lfs fp13,0(r9)
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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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mtfsfi 7,1 /* Set rounding mode toward 0. */
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#ifdef SHARED
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lfs fp10,.LC1-.LC0(r9)
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#else
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lis r9,.LC1@ha
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lfs fp10,.LC1@l(r9)
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#endif
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ble- cr6,.L4
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fadd fp1,fp1,fp10 /* x+= 0.5; */
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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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/* x = 0.0; */
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mtfsf 0x01,fp11 /* restore previous rounding mode. */
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blr
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.L4:
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fsub fp9,fp1,fp10 /* x+= 0.5; */
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bge- cr6,.L9 /* if (x < 0.0) */
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fsub fp1,fp9,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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/* x = -0.0; */
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.L9:
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mtfsf 0x01,fp11 /* restore previous rounding mode. */
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blr
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END (__round)
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weak_alias (__round, round)
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#ifdef NO_LONG_DOUBLE
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weak_alias (__round, roundl)
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strong_alias (__round, __roundl)
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#endif
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#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
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compat_symbol (libm, __round, roundl, GLIBC_2_1)
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#endif
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