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authorUlrich Drepper <drepper@gmail.com>2011-10-15 22:21:53 -0400
committerUlrich Drepper <drepper@gmail.com>2011-10-15 22:21:53 -0400
commit79b195b55af84a9044dfb26ebdc49d9f308829af (patch)
tree954c8b77f3b5eca80ae14e24a2fb2e7fd4a27ff3
parentd4a285692ae21debd4518a6d4980fa7e36d104b5 (diff)
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No need for boundary case handling in x86-32 __ieee_log
-rw-r--r--ChangeLog3
-rw-r--r--sysdeps/i386/i686/fpu/e_log.S53
2 files changed, 4 insertions, 52 deletions
diff --git a/ChangeLog b/ChangeLog
index 426b69f425..96ebe99f3f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
2011-10-15 Ulrich Drepper <drepper@gmail.com>
+ * sysdeps/i386/i686/fpu/e_log.S: No need for the fyl2xp1 use, fyl2x
+ is sufficient, at least on modern CPUs.
+
* sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c: New file.
* sysdeps/ieee754/dbl-64/e_cosh.c: Cleanup.
diff --git a/sysdeps/i386/i686/fpu/e_log.S b/sysdeps/i386/i686/fpu/e_log.S
index c6524b1854..73060b088c 100644
--- a/sysdeps/i386/i686/fpu/e_log.S
+++ b/sysdeps/i386/i686/fpu/e_log.S
@@ -2,34 +2,11 @@
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*
- * 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_log)
@@ -37,22 +14,6 @@ ENTRY(__ieee754_log)
fldl 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
@@ -63,18 +24,6 @@ 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)
- 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(__log_finite)