Data lab initialization

1 files changed, 75 insertions, 0 deletions

diff --git a/datalab-handout/ishow.c b/datalab-handout/ishow.c
new file mode 100644
index 0000000..ffb1df7
--- /dev/null
+++ b/datalab-handout/ishow.c
@@ -0,0 +1,75 @@
+/* Display value of fixed point numbers */
+#include <stdlib.h>
+#include <stdio.h>
+
+/* Extract hex/decimal/or float value from string */
+static int get_num_val(char *sval, unsigned *valp) {
+  char *endp;
+  /* See if it's an integer or floating point */
+  int ishex = 0;
+  int isfloat = 0;
+  int i;
+  for (i = 0; sval[i]; i++) {
+    switch (sval[i]) {
+    case 'x':
+    case 'X':
+      ishex = 1;
+      break;
+    case 'e':
+    case 'E':
+      if (!ishex)
+	isfloat = 1;
+      break;
+    case '.':
+      isfloat = 1;
+      break;
+    default:
+      break;
+    }
+  }
+  if (isfloat) {
+    return 0; /* Not supposed to have a float here */
+  } else {
+    long long int llval = strtoll(sval, &endp, 0);
+    long long int upperbits = llval >> 31;
+    /* will give -1 for negative, 0 or 1 for positive */
+    if (valp && (upperbits == 0 || upperbits == -1 || upperbits == 1)) {
+      *valp = (unsigned) llval;
+      return 1;
+    }
+    return 0;
+  }
+}
+
+void show_int(unsigned uf)
+{
+  printf("Hex = 0x%.8x,\tSigned = %d,\tUnsigned = %u\n",
+	 uf, (int) uf, uf);
+}
+
+
+void usage(char *fname) {
+  printf("Usage: %s val1 val2 ...\n", fname);
+  printf("Values may be given in hex or decimal\n");
+  exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+  int i;
+  unsigned uf;
+  if (argc < 2)
+    usage(argv[0]);
+  for (i = 1; i < argc; i++) {
+    char *sval = argv[i];
+    if (get_num_val(sval, &uf)) {
+      show_int(uf);
+    } else {
+      printf("Cannot convert '%s' to 32-bit number\n", sval);
+    }
+  }
+  return 0;
+}
+
+
+