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-rw-r--r--sysdeps/libm-i387/e_log10l.S52
1 files changed, 48 insertions, 4 deletions
diff --git a/sysdeps/libm-i387/e_log10l.S b/sysdeps/libm-i387/e_log10l.S
index cfddb5ce2a..f0b8f325a7 100644
--- a/sysdeps/libm-i387/e_log10l.S
+++ b/sysdeps/libm-i387/e_log10l.S
@@ -3,15 +3,59 @@
* Public domain.
*
* Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.
+ *
+ * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>.
*/
#include <machine/asm.h>
RCSID("$NetBSD: $")
+#ifdef __ELF__
+ .section .rodata
+#else
+ .text
+#endif
+ .align ALIGNARG(4)
+ 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_log10l)
- fldlg2
- fldt 4(%esp)
- fyl2x
+ fldlg2 // log10(2)
+ fldt 4(%esp) // x : log10(2)
+#ifdef PIC
+ call 1f
+1: popl %edx
+ addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx
+#endif
+ fld %st // x : x : log10(2)
+ fsubl MO(one) // x-1 : x : log10(2)
+ fld %st // x-1 : x-1 : x : log10(2)
+ fabs // |x-1| : x-1 : x : log10(2)
+ fcompl MO(limit) // x-1 : x : log10(2)
+ fnstsw // x-1 : x : log10(2)
+ sahf
+ ja 2f
+ fstp %st(1) // x-1 : log10(2)
+ fyl2xp1 // log10(x)
+ ret
+
+2: fincstp // x : log10(2)
+ fyl2x // log10(x)
ret
-PSEUDO_END(__ieee754_log10l)
+END(__ieee754_log10l)