initial

nibble.c

@@ -0,0 +1,77 @@
+#include "nibble.h"
+#include <stdio.h>
+
+bcd bcd_zeros() {
+  bcd bcd;
+  memset(bcd.internal, 0, sizeof(bcd.internal));
+  return bcd;
+}
+
+#define bcd_from_n(X) {\
+  int i;\
+  bcd res = bcd_zeros();\
+  for (i = 9; i >= 0; --i) {\
+    if (!X) break;\
+    res.internal[i] = (X % 10);\
+    X /= 10;\
+    if (!X) break;\
+    res.internal[i] += (X % 10) << 4;\
+    X /= 10;\
+  }\
+  return res;\
+}
+
+bcd bcd_from_8(uint8_t x) {
+  bcd_from_n(x);
+}
+
+bcd bcd_from_16(uint16_t x) {
+  bcd_from_n(x);
+}
+
+bcd bcd_from_32(uint32_t x) {
+  bcd_from_n(x);
+}
+
+bcd bcd_from_64(uint64_t x) {
+  bcd_from_n(x);
+}
+
+uint8_t bcd_digits(bcd x) {
+  int i;
+  for (i = 0; i < 20; i+=2) {
+    if (x.internal[i/2] != 0) {
+      if (!(x.internal[i/2]&0xf0)) i++;
+      break;
+    }
+  }
+  return 20-i;
+}
+
+uint64_t bcd_to_64(bcd x) {
+  int i;
+  uint64_t res = 0;
+
+  for (i = 0; i < 10; ++i) {
+    res *= 100;
+    res += ((x.internal[i] & 0xf0) >> 4) * 10;
+    res += (x.internal[i] & 0xf);
+  }
+
+  return res;
+}
+
+char* bcd_to_string(bcd x) {
+  int i = 0;
+  uint8_t n = bcd_digits(x);
+  int to = 10-(n+1)/2;
+  char* res = malloc(n+1);
+
+  for (i = 0; i < n; i+=2, to++) {
+    res[i]   = ((x.internal[to] & 0xf0) >> 4) + '0';
+    res[i+1] = (x.internal[to] & 0xf) + '0';
+  }
+
+  res[n] = '\0';
+  return res;
+}