mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 08:40:07 +00:00
01189b083b
For the -ffinite-math-only versions of various x86_64 and x86 log* functions, a zero result from log* (1) is returned with incorrect sign in round-downward mode. This patch fixes this in a similar way to the previous fixes for the non-*_finite versions of the functions. Tested for x86_64 and x86 (including an i586 build), together with a patch that will be applied separately to enable the main libm-test.inc tests for the finite-math-only functions. [BZ #19213] * sysdeps/i386/fpu/e_log.S (__log_finite): Ensure +0 is always returned for argument 1. * sysdeps/i386/fpu/e_logf.S (__logf_finite): Likewise. * sysdeps/i386/fpu/e_logl.S (__logl_finite): Likewise. * sysdeps/i386/i686/fpu/e_logl.S (__logl_finite): Likewise. * sysdeps/x86_64/fpu/e_log10l.S (__log10l_finite): Likewise. * sysdeps/x86_64/fpu/e_log2l.S (__log2l_finite): Likewise. * sysdeps/x86_64/fpu/e_logl.S (__logl_finite): Likewise.
93 lines
1.8 KiB
ArmAsm
93 lines
1.8 KiB
ArmAsm
/*
|
|
* Written by J.T. Conklin <jtc@netbsd.org>.
|
|
* Public domain.
|
|
*
|
|
* 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_log)
|
|
fldln2 // log(2)
|
|
fldl 4(%esp) // x : log(2)
|
|
fxam
|
|
fnstsw
|
|
#ifdef PIC
|
|
LOAD_PIC_REG (dx)
|
|
#endif
|
|
fld %st // x : x : log(2)
|
|
sahf
|
|
jc 3f // in case x is NaN or +-Inf
|
|
4: fsubl MO(one) // x-1 : x : log(2)
|
|
fld %st // x-1 : x-1 : x : log(2)
|
|
fabs // |x-1| : x-1 : x : log(2)
|
|
fcompl MO(limit) // x-1 : x : log(2)
|
|
fnstsw // x-1 : x : log(2)
|
|
andb $0x45, %ah
|
|
jz 2f
|
|
fxam
|
|
fnstsw
|
|
andb $0x45, %ah
|
|
cmpb $0x40, %ah
|
|
jne 5f
|
|
fabs // log(1) is +0 in all rounding modes.
|
|
5: fstp %st(1) // x-1 : log(2)
|
|
fyl2xp1 // log(x)
|
|
ret
|
|
|
|
2: fstp %st(0) // x : log(2)
|
|
fyl2x // log(x)
|
|
ret
|
|
|
|
3: jp 4b // in case x is +-Inf
|
|
fstp %st(1)
|
|
fstp %st(1)
|
|
ret
|
|
END (__ieee754_log)
|
|
|
|
ENTRY(__log_finite)
|
|
fldln2 // log(2)
|
|
fldl 4(%esp) // x : log(2)
|
|
#ifdef PIC
|
|
LOAD_PIC_REG (dx)
|
|
#endif
|
|
fld %st // x : x : log(2)
|
|
fsubl MO(one) // x-1 : x : log(2)
|
|
fld %st // x-1 : x-1 : x : log(2)
|
|
fabs // |x-1| : x-1 : x : log(2)
|
|
fcompl MO(limit) // x-1 : x : log(2)
|
|
fnstsw // x-1 : x : log(2)
|
|
andb $0x45, %ah
|
|
jz 2b
|
|
fxam
|
|
fnstsw
|
|
andb $0x45, %ah
|
|
cmpb $0x40, %ah
|
|
jne 6f
|
|
fabs // log(1) is +0 in all rounding modes.
|
|
6: fstp %st(1) // x-1 : log(2)
|
|
fyl2xp1 // log(x)
|
|
ret
|
|
END(__log_finite)
|