Fix intermittent ATTN PRNG failures.

    Failing (repeatedly generating the same number after some number of
    calls to the prng) about 20% of the time.

Change-Id: I2d429856ecb5c3492aa414dfd3124d73af0878c0
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/1886
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>

3 files changed, 20 insertions, 12 deletions

diff --git a/src/usr/diag/attn/test/attntest.C b/src/usr/diag/attn/test/attntest.C
index 1be9647c6..22fc032ba 100644
--- a/src/usr/diag/attn/test/attntest.C
+++ b/src/usr/diag/attn/test/attntest.C
@@ -43,10 +43,12 @@ namespace ATTN
 uint64_t randint(uint64_t i_min, uint64_t i_max)
 {
     static bool setup = false;
-    static uint64_t hapSeed = generate_random();
+    static uint64_t seed = 0;
 
     if(!setup)
     {
+        uint64_t hapSeed = generate_random();
+
         if(!hapSeed)
         {
             ATTN_DBG("falling back to timebase seed for PRNG");
@@ -56,19 +58,20 @@ uint64_t randint(uint64_t i_min, uint64_t i_max)
             ATTN_DBG("hapseed: %d", hapSeed);
         }
 
+        seed = hapSeed ? hapSeed : getTB() + 1;
+
         setup = true;
     }
 
-    static uint64_t seed = hapSeed ? hapSeed : getTB() + 1;
-
     uint64_t lo, hi;
 
     seed = seed * seed;
     lo = (seed & 0x0000ffffffff0000ull) >> 16;
     hi = (seed & 0x000000000000ffffull) << 32;
     hi |= (seed & 0xffff000000000000ull);
-    seed = lo;
+    seed = (lo | hi) + 2;
 
+    static const uint64_t randMax = 0xfffffffffffffffe;
     uint64_t min = i_min, max = i_max;
 
     if(i_min > i_max)
@@ -76,7 +79,12 @@ uint64_t randint(uint64_t i_min, uint64_t i_max)
         swap(min, max);
     }
 
-    return ((lo | hi) % (i_max +1 - i_min)) + i_min;
+    if(max > randMax)
+    {
+        max = randMax;
+    }
+
+    return ((lo | hi) % (max +1 - min)) + min;
 }
 
 ATTENTION_VALUE_TYPE getRandomAttentionType()
diff --git a/src/usr/diag/attn/test/attntestmem.H b/src/usr/diag/attn/test/attntestmem.H
index 38046df89..9b472761b 100644
--- a/src/usr/diag/attn/test/attntestmem.H
+++ b/src/usr/diag/attn/test/attntestmem.H
@@ -91,7 +91,7 @@ class AttnMemTest: public CxxTest::TestSuite
 
                 // put some random data in the mask register
 
-                uint64_t randomData = randint(0, 0xffffffff);
+                uint64_t randomData = randint(0, 0xffffffffffffffffull);
                 uint64_t maskbits = 0;
 
                 if(!IPOLL::getCheckbits(HOST, maskbits))
@@ -202,7 +202,7 @@ class AttnMemTest: public CxxTest::TestSuite
 
                 // put some random data in the mask register
 
-                uint64_t randomData = randint(0, 0xffffffff);
+                uint64_t randomData = randint(0, 0xffffffffffffffffull);
                 uint64_t maskbits = 0;
 
                 if(!IPOLL::getCheckbits(HOST, maskbits))
@@ -239,7 +239,7 @@ class AttnMemTest: public CxxTest::TestSuite
                 // verify that the attn was masked, and that
                 // other bits weren't touched
 
-                if(!(data & ~maskbits))
+                if(!(~data & maskbits))
                 {
                     TS_FAIL("attention not unmasked");
                     break;
diff --git a/src/usr/diag/attn/test/attntestproc.H b/src/usr/diag/attn/test/attntestproc.H
index cb62fc0f9..a9f8001a1 100644
--- a/src/usr/diag/attn/test/attntestproc.H
+++ b/src/usr/diag/attn/test/attntestproc.H
@@ -87,7 +87,7 @@ class AttnProcTest: public CxxTest::TestSuite
 
                 // put some random data in the mask register
 
-                uint64_t randomData = randint(0, 0xffffffff);
+                uint64_t randomData = randint(0, 0xffffffffffffffffull);
                 uint64_t maskbits = 0;
 
                 if(!IPOLL::getCheckbits(d.attnType, maskbits))
@@ -195,7 +195,7 @@ class AttnProcTest: public CxxTest::TestSuite
 
                 // put some random data in the mask register
 
-                uint64_t randomData = randint(0, 0xffffffff);
+                uint64_t randomData = randint(0, 0xffffffffffffffffull);
                 uint64_t maskbits = 0;
 
                 if(!IPOLL::getCheckbits(d.attnType, maskbits))
@@ -229,10 +229,10 @@ class AttnProcTest: public CxxTest::TestSuite
                     break;
                 }
 
-                // verify that the attn was masked, and that
+                // verify that the attn was unmasked, and that
                 // other bits weren't touched
 
-                if(!(data & ~maskbits))
+                if(!(~data & maskbits))
                 {
                     TS_FAIL("attention not unmasked");
                     break;