glibc/sysdeps/i386/fpu/e_log10l.S
Joseph Myers 09096b3615 Fix i386/x86_64 log10l (sNaN) (bug 20228).
The i386/x86_64 versions of log10l return sNaN for sNaN input.  This
patch fixes them to add a NaN input to itself so that qNaN is returned
in this case.

Tested for x86_64 and x86.

	[BZ #20228]
	* sysdeps/i386/fpu/e_log10l.S (__ieee754_log10l): Add NaN input to
	itself.
	* sysdeps/x86_64/fpu/e_log10l.S (__ieee754_log10l): Likewise.
	* math/libm-test.inc (log10_test_data): Add sNaN tests.
2016-06-08 22:59:18 +00:00

72 lines
1.4 KiB
ArmAsm

/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*
* Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.
*
* Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>.
*/
#include <machine/asm.h>
.section .rodata.cst8,"aM",@progbits,8
.p2align 3
.type one,@object
one: .double 1.0
ASM_SIZE_DIRECTIVE(one)
/* It is not important that this constant is precise. It is only
a value which is known to be on the safe side for using the
fyl2xp1 instruction. */
.type limit,@object
limit: .double 0.29
ASM_SIZE_DIRECTIVE(limit)
#ifdef PIC
# define MO(op) op##@GOTOFF(%edx)
#else
# define MO(op) op
#endif
.text
ENTRY(__ieee754_log10l)
fldlg2 // log10(2)
fldt 4(%esp) // x : log10(2)
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fxam
fnstsw
fld %st // x : x : log10(2)
sahf
jc 3f // in case x is NaN or ±Inf
4: fsubl MO(one) // x-1 : x : log10(2)
fld %st // x-1 : x-1 : x : log10(2)
fabs // |x-1| : x-1 : x : log10(2)
fcompl MO(limit) // x-1 : x : log10(2)
fnstsw // x-1 : x : log10(2)
andb $0x45, %ah
jz 2f
fxam
fnstsw
andb $0x45, %ah
cmpb $0x40, %ah
jne 5f
fabs // log10(1) is +0 in all rounding modes.
5: fstp %st(1) // x-1 : log10(2)
fyl2xp1 // log10(x)
ret
2: fstp %st(0) // x : log10(2)
fyl2x // log10(x)
ret
3: jp 4b // in case x is ±Inf
fstp %st(1)
fstp %st(1)
fadd %st(0)
ret
END(__ieee754_log10l)
strong_alias (__ieee754_log10l, __log10l_finite)