1 files changed, 38 insertions, 0 deletions
diff --git a/util.c b/util.c
new file mode 100644
index 0000000..8be15a4
--- /dev/null
+++ b/util.c
@@ -0,0 +1,38 @@
+#include "project.h"
+
+int set_parity (uint8_t *d, unsigned s, unsigned e)
+{
+  unsigned i;
+  uint8_t p = 0;
+
+  for (i = s; i <= e; ++i)
+    p ^= d[i];
+
+  return !p;
+}
+
+
+void  bcd_set (uint8_t *d, unsigned s, unsigned e, unsigned v)
+{
+  unsigned c, i, w;
+
+
+  w = v % 10;
+
+  for (i = e, c = 1 ; i >= s; --i) {
+
+    d[i] = !! (c & w) ;
+
+    if (c & 0x77777777)
+      c <<= 1;
+    else {
+      c >>= 3;
+      c *= 10;
+      v = v / 10;
+      w = v % 10;
+    }
+  }
+}
+
+
+