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-rw-r--r--sysdeps/i386/fpu/e_ilogbl.S44
1 files changed, 44 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/e_ilogbl.S b/sysdeps/i386/fpu/e_ilogbl.S
new file mode 100644
index 0000000000..6e2be9a300
--- /dev/null
+++ b/sysdeps/i386/fpu/e_ilogbl.S
@@ -0,0 +1,44 @@
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Changes for long double by Ulrich Drepper <drepper@cygnus.com>
+ * Public domain.
+ */
+
+#include <machine/asm.h>
+
+RCSID("$NetBSD: $")
+
+ENTRY(__ieee754_ilogbl)
+	fldt	4(%esp)
+/* I added the following ugly construct because ilogb(+-Inf) is
+   required to return INT_MAX in ISO C99.
+   -- jakub@redhat.com.  */
+	fxam			/* Is NaN or +-Inf?  */
+	fstsw   %ax
+	movb    $0x45, %dh
+	andb    %ah, %dh
+	cmpb    $0x05, %dh
+	je      1f		/* Is +-Inf, jump.  */
+	cmpb    $0x40, %dh
+	je      2f		/* Is +-0, jump.  */
+
+	fxtract
+	pushl	%eax
+	cfi_adjust_cfa_offset (4)
+	fstp	%st
+
+	fistpl	(%esp)
+	fwait
+	popl	%eax
+	cfi_adjust_cfa_offset (-4)
+
+	ret
+
+1:	fstp	%st
+	movl	$0x7fffffff, %eax
+	ret
+2:	fstp	%st
+	movl	$0x80000000, %eax	/* FP_ILOGB0  */
+	ret
+END (__ieee754_ilogbl)
+weak_alias (__ieee754_ilogbl, __ilogbl_finite)