glibc/sysdeps/powerpc/powerpc32/fpu/s_truncf.S
Joseph Myers 1f921a93e4 Do not raise "inexact" from powerpc32 ceil, floor, trunc (bug 15479).
Continuing fixes for ceil, floor and trunc functions not to raise the
"inexact" exception, this patch fixes the versions used on older
powerpc32 processors.  As was done with the round implementations some
time ago, the save of floating-point state is moved after the first
floating-point operation on the input to ensure that any "invalid"
exception from signaling NaN input is included in the saved state, and
then the whole state gets restored rather than just the rounding mode.

This has no effect on configurations using the power5+ code, since
such processors can do these operations with a single instruction (and
those instructions do not set "inexact", so are correct for TS 18661-1
semantics).

Tested for powerpc32.

	[BZ #15479]
	* sysdeps/powerpc/powerpc32/fpu/s_ceil.S (__ceil): Move save of
	floating-point state after first floating-point operation on
	input.  Restore full floating-point state instead of just rounding
	mode.
	* sysdeps/powerpc/powerpc32/fpu/s_ceilf.S (__ceilf): Likewise.
	* sysdeps/powerpc/powerpc32/fpu/s_floor.S (__floor): Likewise.
	* sysdeps/powerpc/powerpc32/fpu/s_floorf.S (__floorf): Likewise.
	* sysdeps/powerpc/powerpc32/fpu/s_trunc.S (__trunc): Likewise.
	* sysdeps/powerpc/powerpc32/fpu/s_truncf.S (__truncf): Likewise.
2016-05-25 16:53:23 +00:00

77 lines
2.3 KiB
ArmAsm

/* truncf function. PowerPC32 version.
Copyright (C) 2004-2016 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, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
.section .rodata.cst4,"aM",@progbits,4
.align 2
.LC0: /* 2**23 */
.long 0x4b000000
/* float [fp1] truncf (float x [fp1])
IEEE 1003.1 trunc function. IEEE specifies "trunc to the integer
value, in floating format, nearest to but no larger in magnitude
then the argument."
We set "round toward Zero" mode and trunc by adding +-2**23 then
subtracting +-2**23. */
.section ".text"
ENTRY (__truncf)
#ifdef SHARED
mflr r11
cfi_register(lr,r11)
SETUP_GOT_ACCESS(r9,got_label)
addis r9,r9,.LC0-got_label@ha
lfs fp13,.LC0-got_label@l(r9)
mtlr r11
cfi_same_value (lr)
#else
lis r9,.LC0@ha
lfs fp13,.LC0@l(r9)
#endif
fabs fp0,fp1
fsubs fp12,fp13,fp13 /* generate 0.0 */
fcmpu cr7,fp0,fp13 /* if (fabs(x) > TWO23) */
mffs fp11 /* Save current FPU rounding mode and
"inexact" state. */
fcmpu cr6,fp1,fp12 /* if (x > 0.0) */
bnllr- cr7
mtfsfi 7,1 /* Set rounding toward 0 mode. */
ble- cr6,.L4
fadds fp1,fp1,fp13 /* x+= TWO23; */
fsubs fp1,fp1,fp13 /* x-= TWO23; */
fabs fp1,fp1 /* if (x == 0.0) */
/* x = 0.0; */
mtfsf 0xff,fp11 /* Restore previous rounding mode and
"inexact" state. */
blr
.L4:
bge- cr6,.L9 /* if (x < 0.0) */
fsubs fp1,fp1,fp13 /* x-= TWO23; */
fadds fp1,fp1,fp13 /* x+= TWO23; */
fnabs fp1,fp1 /* if (x == 0.0) */
/* x = -0.0; */
.L9:
mtfsf 0xff,fp11 /* Restore previous rounding mode and
"inexact" state. */
blr
END (__truncf)
weak_alias (__truncf, truncf)