Initial commit: Add starter code for Datalab

1 files changed, 69 insertions, 0 deletions

diff --git a/ishow.c b/ishow.c
new file mode 100644
index 0000000..9178c40
--- /dev/null
+++ b/ishow.c
@@ -0,0 +1,69 @@
+/* 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;
+}