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authorUlrich Drepper <drepper@gmail.com>2011-10-14 23:41:47 -0400
committerUlrich Drepper <drepper@gmail.com>2011-10-14 23:41:47 -0400
commit38ad40ceca8ba35761e79cfce4aaef0d0f7583e6 (patch)
tree336de2d8f4b91a770418446fe2c322662d321bcd /sysdeps/i386/fpu/e_log.S
parent396a21b1d016c52e011f8921e0728aa62a1e9df0 (diff)
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Optimize x86-32 log
Diffstat (limited to 'sysdeps/i386/fpu/e_log.S')
-rw-r--r--sysdeps/i386/fpu/e_log.S20
1 files changed, 19 insertions, 1 deletions
diff --git a/sysdeps/i386/fpu/e_log.S b/sysdeps/i386/fpu/e_log.S
index 8110a84..a2e4d89 100644
--- a/sysdeps/i386/fpu/e_log.S
+++ b/sysdeps/i386/fpu/e_log.S
@@ -62,4 +62,22 @@ ENTRY(__ieee754_log)
fstp %st(1)
ret
END (__ieee754_log)
-strong_alias (__ieee754_log, __log_finite)
+
+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)
+ fcompl MO(limit) // x-1 : x : log(2)
+ fnstsw // x-1 : x : log(2)
+ andb $0x45, %ah
+ jz 2b
+ fstp %st(1) // x-1 : log(2)
+ fyl2xp1 // log(x)
+ ret
+END(__log_finite)