complete lab07

lab07/lab7.c

@@ -0,0 +1,90 @@
+#include <stdint.h>
+#include <stdio.h>
+
+#define SIGN_MASK 0x0000000000000001
+
+long getClamp(long q, long min, long max)
+{
+    long diffToMin;
+    long diffToMax;
+    long diffToMinSign;
+    long diffToMaxSign;
+
+    diffToMin = q + (~min + 1);
+    diffToMax = q + (~max + 1);
+    diffToMinSign = (diffToMin >> 63) & SIGN_MASK;
+    diffToMaxSign = (diffToMax >> 63) & SIGN_MASK;
+
+    // If diff to min is 0, or the diff to min
+    // is greater than the min (positive sign),
+    // then check max
+    if (diffToMin == 0 || diffToMinSign == 0)
+    {
+        // if the diff to min is 0, or the diff to max
+        // is less than the min, (negative sign),
+        // return q
+        // otherwise return max
+        return (diffToMax == 0 || diffToMaxSign == 1) ? q : max;
+    }
+
+    return min;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc != 3)
+    {
+        perror("Usage: lab5.c <input_file> <output_file>\n");
+        return 1;
+    }
+
+    char *inputPath;
+    char *outputPath;
+    FILE *inputFile;
+    FILE *outputFile;
+
+    inputPath  = argv[1];
+    outputPath = argv[2];
+    inputFile  = fopen(inputPath, "r");
+    outputFile = fopen(outputPath, "w");
+
+    if (inputFile == NULL || outputFile == NULL)
+    {
+        perror("Failed to open file");
+        return 1;
+    }
+
+    long bits;
+    long min;
+    long max;
+    long x;
+    long y;
+    long q;
+    long result;
+
+    fscanf(inputFile, "%ld", &bits);
+    fscanf(inputFile, "%ld", &x);
+    fscanf(inputFile, "%ld", &y);
+
+    min = (1 << (bits - 1)) * -1;
+    max = (1 << (bits - 1)) - 1;
+
+    if (x == 0 && y == 0)
+    {
+        fprintf(outputFile, "min: %ld\t0x%016lx\n", min, min);
+        fprintf(outputFile, "max: %ld\t0x%016lx\n", max, max);
+    }
+    else
+    {
+        q = x * y;
+
+        result = getClamp(q, min, max);
+
+        fprintf(outputFile, "%ld\n", result);
+    }
+
+    fclose(inputFile);
+    fclose(outputFile);
+
+    return 0;
+}