I'm checking this in; yet another case of a missing port from branch-1_4 (fixed
6 months ago in 1.4.5, no less).
2007-04-03 Eric Blake <[EMAIL PROTECTED]>
* modules/m4.c (numb_ratio, numb_divide, numb_modulo): Avoid
SIGFPE on x86 architectures.
Reported by Ralf Wildenhues.
Index: modules/m4.c
===================================================================
RCS file: /sources/m4/m4/modules/m4.c,v
retrieving revision 1.105
diff -u -r1.105 m4.c
--- modules/m4.c 2 Apr 2007 12:06:23 -0000 1.105
+++ modules/m4.c 3 Apr 2007 21:01:00 -0000
@@ -1095,9 +1095,13 @@
#define numb_negate(x) ((x) = (- (x)))
#define numb_times(x, y) ((x) = ((x) * (y)))
-#define numb_ratio(x, y) ((x) = ((x) / ((y))))
-#define numb_divide(x, y) (*(x) = (*(x) / (*(y))))
-#define numb_modulo(c, x, y) (*(x) = (*(x) % *(y)))
+/* Be careful of x86 SIGFPE. */
+#define numb_ratio(x, y) \
+ (((y) == -1) ? (numb_negate (x)) : ((x) /= (y)))
+#define numb_divide(x, y) \
+ ((*(y) == -1) ? (numb_negate (*(y))) : (*(x) /= *(y)))
+#define numb_modulo(c, x, y) \
+ ((*(y) == -1) ? (*(x) = numb_ZERO) : (*(x) %= *(y)))
/* numb_invert is only used in the context of x**-y, which integral math
does not support. */
#define numb_invert(x) return NEGATIVE_EXPONENT
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