util: move rand_xorshift128plus() to utils

V2: pass the seed to rand_xorshift128plus() so that we can isolate
    its uses.

Reviewed-by: Grazvydas Ignotas <[email protected]>
Reviewed-by: Nicolai Hähnle <[email protected]>

1 files changed, 5 insertions, 19 deletions

diff --git a/src/gallium/drivers/radeon/r600_test_dma.c b/src/gallium/drivers/radeon/r600_test_dma.c
index f7e9eb5fc38..8b4149af53c 100644
--- a/src/gallium/drivers/radeon/r600_test_dma.c
+++ b/src/gallium/drivers/radeon/r600_test_dma.c
@@ -26,26 +26,10 @@
 
 #include "r600_pipe_common.h"
 #include "util/u_surface.h"
+#include "util/rand_xor.h"
 
 static uint64_t seed_xorshift128plus[2];
 
-/* Super fast random number generator.
- *
- * This rand_xorshift128plus function by Sebastiano Vigna belongs
- * to the public domain.
- */
-static uint64_t rand_xorshift128plus(void)
-{
-	uint64_t *s = seed_xorshift128plus;
-
-	uint64_t s1 = s[0];
-	const uint64_t s0 = s[1];
-	s[0] = s0;
-	s1 ^= s1 << 23;
-	s[1] = s1 ^ s0 ^ (s1 >> 18) ^ (s0 >> 5);
-	return s[1] + s0;
-}
-
 #define RAND_NUM_SIZE 8
 
 /* The GPU blits are emulated on the CPU using these CPU textures. */
@@ -91,8 +75,10 @@ static void set_random_pixels(struct pipe_context *ctx,
 			assert(t->stride % RAND_NUM_SIZE == 0);
 			assert(cpu->stride % RAND_NUM_SIZE == 0);
 
-			for (x = 0; x < size; x++)
-				*ptr++ = *ptr_cpu++ = rand_xorshift128plus();
+			for (x = 0; x < size; x++) {
+				*ptr++ = *ptr_cpu++ =
+					rand_xorshift128plus(seed_xorshift128plus);
+			}
 		}
 	}