docs/probe_math_exception.c:

	update example
libc/sysdeps/linux/i386/bits/mathinline.h:
	improve __finite() macro, add __finitef macro
	(why they aren't always macros? why aren't they arch independent?)
libm/math_private.h:
	much better comments on math_opt_barrier() and math_force_eval()
libm/s_finite[f].c:
	improve out-of-line __finite[f]() too (one byte less, yay...)

1 files changed, 28 insertions, 5 deletions

diff --git a/docs/probe_math_exception.c b/docs/probe_math_exception.c
index dbeccc5cc..dbc9020d4 100644
--- a/docs/probe_math_exception.c
+++ b/docs/probe_math_exception.c
@@ -5,20 +5,40 @@
 #define _ISOC99_SOURCE 1
 #define _GNU_SOURCE    1
 
+#include <stdint.h>
 #include <math.h>
 #include <fenv.h>
 #include <stdio.h>
 
 int main(int argc, char **argv)
 {
-	float infF = HUGE_VALF * 2;
+	float largest, small, t, inf_float;
+
+	largest = small = 1;
+	while (1) {
+		t = largest + small;
+		/* optimizations may make plain "t == largest" unreliable */
+		if (memcmp(&t, &largest, sizeof(float)) == 0)
+			break;
+		if (isfinite(t)) {
+			largest = t;
+			small *= 2;
+			continue;
+		}
+		small /= 2;
+	}
+	inf_float = largest + largest;
+	//printf("%.40g ", largest);
+	//printf("[%llx]\n", (long long) (*(uint32_t *)&largest));
 
 	feclearexcept(FE_ALL_EXCEPT);
 
-//	printf("%.40e\n", 1.0 / 0.0); // FE_DIVBYZERO
-//	printf("%.40e\n", nextafterf(HUGE_VALF, infF)); // no exceptions in glibc 2.4
+	//t = 1.0 / 0.0; // simple test: FE_DIVBYZERO
+	//t = nextafterf(largest, 1); // glibc 2.8: no math exceptions raised
+	//t = nextafterf(largest, largest); // glibc 2.8: no math exceptions raised
+	//t = nextafterf(largest, inf_float); // glibc 2.8: FE_INEXACT FE_OVERFLOW
 
-#define PREX(ex) do { if (fetestexcept(ex)) printf(#ex); } while(0)
+#define PREX(ex) do { if (fetestexcept(ex)) printf(#ex " "); } while(0)
 #ifdef FE_INEXACT
 	PREX(FE_INEXACT);
 #endif
@@ -36,6 +56,9 @@ int main(int argc, char **argv)
 #endif
 	if (fetestexcept(FE_ALL_EXCEPT))
 		printf("\n");
-	printf("done\n");
+	else
+		printf("no math exceptions raised\n");
+
+	printf("%.40g\n", t);
 	return 0;
 }