glibc/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S

61 lines
2.1 KiB
ArmAsm

/* llroundf function. PowerPC64 version.
Copyright (C) 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
.section ".toc","aw"
.LC0: /* -0.0 */
.tc FD_00000000_0[TC],0x0000000000000000
.LC1: /* 0.5 */
.tc FD_3fe00000_0[TC],0x3fe0000000000000
.section ".text"
/* long long [r3] llroundf (float x [fp1])
IEEE 1003.1 llroundf function. IEEE specifies "roundf to the nearest
integer value, roundfing halfway cases away from zero, regardless of
the current roundfing mode." However PowerPC Architecture defines
"roundf to Nearest" as "Choose the best approximation. In case of a
tie, choose the one that is even (least significant bit o).".
So we can't use the PowerPC "round to Nearest" mode. Instead we set
"round toward Zero" mode and round by adding +-0.5 before rounding
to the integer value. */
ENTRY (__llroundf)
CALL_MCOUNT 0
lfd fp12,.LC0@toc(2)
lfd fp10,.LC1@toc(2)
fcmpu cr6,fp1,fp12 /* if (x < 0.0) */
fsubs fp3,fp1,fp10 /* x-= 0.5; */
ble- cr6,.L9
fadds fp3,fp1,fp10 /* x+= 0.5; */
.L9:
fctidz fp2,fp3 /* Convert To Integer DW round toward 0. */
stfd fp2,-16(r1)
nop /* Insure the following load is in a different dispatch group */
nop /* to avoid pipe stall on POWER4&5. */
nop
ld r3,-16(r1)
blr
END (__llroundf)
strong_alias (__llroundf, __lroundf)
weak_alias (__llroundf, llroundf)
weak_alias (__lroundf, lroundf)