From: Ulrich Drepper <drepper@gmail.com>
Date: Sat, 15 Oct 2011 22:09:12 +0000 (-0400)
Subject: No need for boundary case handling in x86-32 __ieee_logf
X-Git-Tag: upstream/2.30~11995
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ba1a0d5938b53454a249d679ab90baf541cd91ad;p=external%2Fglibc.git

No need for boundary case handling in x86-32 __ieee_logf
---

diff --git a/ChangeLog b/ChangeLog
index 3e71646..44580a5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -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.
diff --git a/sysdeps/i386/i686/fpu/e_logf.S b/sysdeps/i386/i686/fpu/e_logf.S
index 64f8807..6fd39d5 100644
--- a/sysdeps/i386/i686/fpu/e_logf.S
+++ b/sysdeps/i386/i686/fpu/e_logf.S
@@ -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)