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Diffstat (limited to 'sysdeps/i386/fpu/s_ilogbl.S')
-rw-r--r--sysdeps/i386/fpu/s_ilogbl.S14
1 files changed, 14 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/s_ilogbl.S b/sysdeps/i386/fpu/s_ilogbl.S
index 1dad93a..ed547bd 100644
--- a/sysdeps/i386/fpu/s_ilogbl.S
+++ b/sysdeps/i386/fpu/s_ilogbl.S
@@ -10,6 +10,16 @@ RCSID("$NetBSD: $")
ENTRY(__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. */
+
fxtract
pushl %eax
fstp %st
@@ -19,5 +29,9 @@ ENTRY(__ilogbl)
popl %eax
ret
+
+1: fstp %st
+ movl $0x7fffffff, %eax
+ ret
END (__ilogbl)
weak_alias (__ilogbl, ilogbl)