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Diffstat (limited to 'sysdeps/i386/fpu/s_log2f.S')
-rw-r--r--sysdeps/i386/fpu/s_log2f.S11
1 files changed, 10 insertions, 1 deletions
diff --git a/sysdeps/i386/fpu/s_log2f.S b/sysdeps/i386/fpu/s_log2f.S
index bfdd0ef88e..111dc9c1d9 100644
--- a/sysdeps/i386/fpu/s_log2f.S
+++ b/sysdeps/i386/fpu/s_log2f.S
@@ -40,8 +40,12 @@ ENTRY(__log2f)
 #endif
 	fldl	MO(one)
 	flds	4(%esp)		// x : 1
+	fxam
+	fnstsw
 	fld	%st		// x : x : 1
-	fsub	%st(2), %st	// x-1 : x : 1
+	sahf
+	jc	3f		// in case x is NaN or ħInf
+4:	fsub	%st(2), %st	// x-1 : x : 1
 	fld	%st		// x-1 : x-1 : x : 1
 	fabs			// |x-1| : x-1 : x : 1
 	fcompl	MO(limit)	// x-1 : x : 1
@@ -55,5 +59,10 @@ ENTRY(__log2f)
 2:	fstp	%st(0)		// x : 1
 	fyl2x			// log(x)
 	ret
+
+3:	jp	4b		// in case x is ħInf
+	fstp	%st(1)
+	fstp	%st(1)
+	ret
 END (__log2f)
 weak_alias (__log2f, log2f)