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.
* 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)
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
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)