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authorUlrich Drepper <drepper@redhat.com>2000-12-03 10:00:46 +0000
committerUlrich Drepper <drepper@redhat.com>2000-12-03 10:00:46 +0000
commit79569444efc685121f65d91f5b4eee834830d416 (patch)
tree05e776a4edd548651a6eca18eef62983c5ca7475 /sysdeps/i386
parent06f55c0c1d28a6ef1462c54a94988112070a0c50 (diff)
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Update.
2000-12-03  Ulrich Drepper  <drepper@redhat.com>

	* math/test-misc.c (main): Add tests for frexp.
	Reported by Fred J. Tydeman <tydeman@tybor.com>.
	* sysdeps/i386/fpu/s_frexpl.S: Don't overflow during the computation.
Diffstat (limited to 'sysdeps/i386')
-rw-r--r--sysdeps/i386/fpu/s_frexpl.S20
1 files changed, 20 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/s_frexpl.S b/sysdeps/i386/fpu/s_frexpl.S
index cb943f74c2..2645d220ee 100644
--- a/sysdeps/i386/fpu/s_frexpl.S
+++ b/sysdeps/i386/fpu/s_frexpl.S
@@ -32,6 +32,12 @@
 	ASM_TYPE_DIRECTIVE(two64,@object)
 two64:	.byte 0, 0, 0, 0, 0, 0, 0xf0, 0x43
 	ASM_SIZE_DIRECTIVE(two64)
+	/* The following is LDBL_MAX / ldexp (1.0, 64), the largest
+	   number we can handle the normal way.  */
+	ASM_TYPE_DIRECTIVE(largest,@object)
+largest:
+	.byte 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xbe, 0x7f, 0, 0
+	ASM_SIZE_DIRECTIVE(largest)
 
 #ifdef PIC
 #define MO(op) op##@GOTOFF(%edx)
@@ -63,12 +69,16 @@ ENTRY (BP_SYM (__frexpl))
 	cmpl	$0, %eax
 	je	2f
 
+	cmpl	$0x7fbe, %eax
+	ja	4f
+
 	fldt	VAL0(%esp)
 #ifdef	PIC
 	call	3f
 3:	popl	%edx
 	addl	$_GLOBAL_OFFSET_TABLE_+[.-3b], %edx
 #endif
+
 	fmull	MO(two64)	/* It's not necessary to use a 80bit factor */
 	movl	$-64, %ecx
 	fstpt	VAL0(%esp)
@@ -92,5 +102,15 @@ ENTRY (BP_SYM (__frexpl))
 
 	LEAVE
 	ret
+
+4:	movl	VAL2(%esp), %ecx
+	movl	%ecx, %edx
+	andl	$0x7fff, %ecx
+
+	andl	$0x8000, %edx
+	subl	$16382, %ecx
+	orl	$0x3ffe, %edx
+	movl	%edx, VAL2(%esp)
+	jmp	1b
 END (BP_SYM (__frexpl))
 weak_alias (BP_SYM (__frexpl), BP_SYM (frexpl))