Finish isLessOrEqual

LAB1/bits.c

@@ -254,7 +254,9 @@ int isAsciiDigit(int x) {
  *   Rating: 3
  */
 int conditional(int x, int y, int z) {
-  return 2;
+  x = !!(x);
+  x = ~x+1;
+  return (x&y)|(~x&z);
 }
 /* 
  * isLessOrEqual - if x <= y  then return 1, else return 0 
@@ -264,7 +266,10 @@ int conditional(int x, int y, int z) {
  *   Rating: 3
  */
 int isLessOrEqual(int x, int y) {
-  return 2;
+  int tmp = ~y+1;
+  tmp = tmp+x-1;
+  tmp = tmp >> 31;//如果比y大，则为0，比y小等于，为1
+  return !!tmp;
 }
 //4
 /* 

README.md

@@ -17,3 +17,5 @@ A CSAPP LAB
 3. Finish negate
 
 4. Finish isAsciiDigit
+
+5. Finish isLessOrEqual