X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/910ad5470d913baeaf9d882a22fc1b853318a5da..f9c1dcd9f6e68a8c07cffed697a9c4c8caed6015:/armsrc/util.c

diff --git a/armsrc/util.c b/armsrc/util.c
index 1dd8dc75..be41bad8 100644
--- a/armsrc/util.c
+++ b/armsrc/util.c
@@ -431,3 +431,19 @@ uint32_t RAMFUNC GetCountSspClk(){
 	}
 }
 
+static uint64_t next_random = 1;
+
+/* Generates a (non-cryptographically secure) 32-bit random number.
+ *
+ * We don't have an implementation of the "rand" function or a clock to seed it
+ * with, so we just call GetTickCount the first time to seed ourselves.
+ */
+uint32_t prand() {
+	if (next_random == 1) {
+		next_random = GetTickCount();
+	}
+
+	next_random = next_random * 6364136223846793005 + 1;
+	return (uint32_t)(next_random >> 32) % 0xffffffff;
+}
+