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-rw-r--r--sysdeps/libm-i387/s_log1p.S54
1 files changed, 46 insertions, 8 deletions
diff --git a/sysdeps/libm-i387/s_log1p.S b/sysdeps/libm-i387/s_log1p.S
index ce8665d3a5..10e8a36369 100644
--- a/sysdeps/libm-i387/s_log1p.S
+++ b/sysdeps/libm-i387/s_log1p.S
@@ -7,18 +7,56 @@
RCSID("$NetBSD: s_log1p.S,v 1.7 1995/05/09 00:10:58 jtc Exp $")
+#ifdef __ELF__
+ .section .rodata
+#else
+ .text
+#endif
+ .align ALIGNARG(4)
+ /* The fyl2xp1 can only be used for values in
+ -1 + sqrt(2) / 2 <= x <= 1 - sqrt(2) / 2
+ 0.29 is a safe value.
+ */
+limit: .double 0.29
+one: .double 1.0
+
/*
- * Since the fyl2xp1 instruction has such a limited range:
- * -(1 - (sqrt(2) / 2)) <= x <= sqrt(2) - 1
- * it's not worth trying to use it.
+ * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29,
+ * otherwise fyl2x with the needed extra computation.
*/
-
+ .text
ENTRY(__log1p)
fldln2
- fldl 4(%esp)
- fld1
- faddp
+
+ fldl 4(%esp)
+
+#ifdef PIC
+ call 1f
+1: popl %edx
+ addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx
+#endif
+
+ fld %st
+ fabs
+#ifdef PIC
+ fcompl limit@GOTOFF(%edx)
+#else
+ fcompl limit
+#endif
+ fnstsw
+ sahf
+ jc 2f
+
+#ifdef PIC
+ faddl one@GOTOFF(%edx)
+#else
+ faddl one
+#endif
fyl2x
ret
-PSEUDO_END (__log1p)
+
+2: fyl2xp1
+ ret
+
+END (__log1p)
weak_alias (__log1p, log1p)