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No need for boundary case handling in x86-32 __ieee_logf

This commit is contained in:
Ulrich Drepper 2011-10-15 18:09:12 -04:00
parent e9b25bd930
commit ba1a0d5938
2 changed files with 4 additions and 52 deletions
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3
ChangeLog
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@ -1,5 +1,8 @@
2011-10-15 Ulrich Drepper <drepper@gmail.com>
* sysdeps/i386/i686/fpu/e_logf.S: No need for the fyl2xp1 use, fyl2x
is sufficient, at least on modern CPUs.
* ctype/ctype-info.c (__ctype_init): Define.
* include/ctype.h (__ctype_init): Declare.
(__ctype_b_loc): The variable is always initialized.

53
sysdeps/i386/i686/fpu/e_logf.S
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@ -3,34 +3,11 @@
* Public domain.
* Adapted for float by Ulrich Drepper <drepper@cygnus.com>.
*
* Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>.
* Adapted for i686 instructions.
*/
#include <machine/asm.h>
#ifdef __ELF__
.section .rodata.cst8,"aM",@progbits,8
#else
.text
#endif
.p2align 3
ASM_TYPE_DIRECTIVE(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. */
ASM_TYPE_DIRECTIVE(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_logf)
@ -38,22 +15,6 @@ ENTRY(__ieee754_logf)
flds 4(%esp) // x : log(2)
fucomi %st
jp 3f
#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)
fld MO(limit) // 0.29 : |x-1| : x-1 : x : log(2)
fcomip %st(1) // |x-1| : x-1 : x : log(2)
fstp %st(0) // x-1 : x : log(2)
jc 2f
fstp %st(1) // x-1 : log(2)
fyl2xp1 // log(x)
ret
2: fstp %st(0) // x : log(2)
fyl2x // log(x)
ret
@ -64,18 +25,6 @@ END (__ieee754_logf)
ENTRY(__logf_finite)
fldln2 // log(2)
flds 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)
fld MO(limit) // 0.29 : |x-1| : x-1 : x : log(2)
fcomip %st(1) // |x-1| : x-1 : x : log(2)
fstp %st(0) // x-1 : x : log(2)
jc 2b
fstp %st(1) // x-1 : log(2)
fyl2xp1 // log(x)
fyl2x // log(x)
ret
END(__logf_finite)