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changeset 457:90b1d927912a

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- suite_aggrs: make sure random memory used doesn't ever result in NaN fp values (for every possible address), as this messes with result comparison
author Tassilo Philipp
date Fri, 28 Jan 2022 14:11:21 +0100
parents 20fa684221a1
children 1c18c2377c24
files test/suite_aggrs/globals.c
diffstat 1 files changed, 17 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/test/suite_aggrs/globals.c	Fri Jan 28 10:26:07 2022 +0100
+++ b/test/suite_aggrs/globals.c	Fri Jan 28 14:11:21 2022 +0100
@@ -32,8 +32,22 @@
 
 #define AGGR_MISALIGN 0
 
-static double rand_d()                    { return ( ( (double) rand() )  / ( (double) RAND_MAX ) ); }
-static void   rand_mem(void* p, size_t s) { int i; for(i=0; i<s; ++i) ((char*)p)[i] = (char)rand(); } /* byte by byte is slow, but whatev  */
+static double rand_d()      { return ( ( (double) rand() )  / ( (double) RAND_MAX ) ); }
+
+/* fill mem with random values, make sure no float aligned memory location
+ * results in a NaN, as they always compare to false; so avaid all ones in
+ * exporent (for simplicity we just look at first 7 exponent bits and make sure
+ * they aren't all set, which would work for all IEEE754 precision formats) */
+static void rand_mem__fp_friendly(void* p, size_t s)
+{
+  int i;
+  for(i = 0; i<s; ++i) {
+    char* c = (char*)p;
+    c[i] = (char)rand(); /* slowish, byte by byte, but whatev */
+    if((c[i]&0x7f) == 0x7f)
+      c[i] ^= 1;
+  }
+}
 
 static int calc_max_aggr_size()
 {
@@ -62,7 +76,7 @@
     K_f[i] = (float)     (rand_d() * FLT_MAX);
     K_d[i] = (double)    (((rand_d()-0.5)*2) * DBL_MAX);
     K_a[i] = malloc(maxaggrsize+AGGR_MISALIGN);
-    rand_mem(K_a[i], maxaggrsize+AGGR_MISALIGN);
+    rand_mem__fp_friendly(K_a[i], maxaggrsize+AGGR_MISALIGN);
     K_a[i] = (char*)K_a[i]+AGGR_MISALIGN;
   }
 }