1 files changed, 40 insertions, 0 deletions
diff --git a/test/mppa/lib/prng.c b/test/mppa/lib/prng.c
new file mode 100644
index 00000000..5846038c
--- /dev/null
+++ b/test/mppa/lib/prng.c
@@ -0,0 +1,40 @@
+// https://en.wikipedia.org/wiki/Linear_congruential_generator -> MMIX Donald Knuth
+// modulo 2^64 = no need to do it explicitly
+
+#define MULTIPLIER 6364136223846793005LL
+#define INCREMENT 1442695040888963407LL
+
+static unsigned long long current;
+
+void srand(long long seed){
+    seed = current;
+}
+
+unsigned long long randlong(void){
+    return (current = MULTIPLIER * current + INCREMENT);
+}
+
+#ifdef __UNIT_TEST__
+char bytewise_sum(unsigned long long to_check){
+    char sum = 0;
+
+    for (int i = 0 ; i < 8 ; i++)
+        sum += (to_check & (unsigned long long)(0xFFULL << i*8)) >> i*8;
+
+    return sum;
+}
+
+int main(void){
+    srand(42);
+
+    if (bytewise_sum(0xdeadbeefb00b1355ULL) != 91)
+        return 1;
+
+    for (int i = 0 ; i < 1000 ; i++)
+        randlong();
+
+    unsigned long long last = randlong();
+
+    return !((unsigned char)bytewise_sum(last) == 251);
+}
+#endif // __UNIT_TEST__