add chapters

L1 datalab/datalab-handout/bits.c

@@ -149,7 +149,7 @@ int bitOr(int x, int y) {
  *   Rating: 1
  */
 int specialBits(void) {
-    return 2;
+    return ~(0xD7 << 14);
 }
 //2
 /*
@@ -170,7 +170,7 @@ int isZero(int x) {
  *   Rating: 2
  */
 int anyEvenBit(int x) {
-  return 2;
+  return !!(((((((0x55 << 8) | 0x55) << 8) | 0x55) << 8) | 0x55) & x);
 }
 /* 
  * negate - return -x 
@@ -191,7 +191,8 @@ int negate(int x) {
  *   Rating: 2 
  */
 int leastBitPos(int x) {
-  return 2;
+    // return (((x ^ (x - 1)) >> 1) + 1);
+	return x & (~x + 1);
 }
 //3
 /* 
@@ -236,7 +237,7 @@ int isLess(int x, int y) {
  *   Rating: 4
  */
 int isPower2(int x) {
-  return 2;
+  return !!(x & (x - 1));
 }
 /*
  * bitReverse - Reverse bits in a 32-bit word

chapters/chapter2/exercise_2_11.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void inplace_swap(int *x, int *y) {
+	*y = *x ^ *y;
+	*x = *x ^ *y;
+	*y = *x ^ *y;
+}
+
+void reverse_array(int a[], int cnt) {
+	int first, last;
+	for(first = 0, last = cnt - 1; first < last; first++, last--) {
+		inplace_swap(&a[first], &a[last]);
+	}
+}
+
+void print_array(int a[], int cnt) {
+	int i;
+	for(i = 0; i < cnt; i++) {
+		printf("%d ", a[i]);
+	}
+	printf("\n");
+}
+
+int main(void) {
+	int a[] = {1, 2, 3, 4, 5};
+	int cnt = 5;
+	reverse_array(a, cnt);
+	print_array(a, cnt);
+	return 0;
+}

chapters/chapter2/exercise_2_5.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "show_bytes.h"
+
+int main(void) {
+	int val = 0x87654321;
+	byte_pointer valp = (byte_pointer) &val;
+	show_bytes(valp, 1);
+	show_bytes(valp, 2);
+	show_bytes(valp, 3);
+
+	return 0;
+}

chapters/chapter2/exercise_2_6.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "show_bytes.h"
+
+int main(void) {
+	int ival = 3510593;
+	float fval = 3510593.0;
+	show_bytes((byte_pointer) &ival, sizeof(int));
+	show_bytes((byte_pointer) &fval, sizeof(float));
+
+	return 0;
+}

chapters/chapter2/exercise_2_7.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "show_bytes.h"
+
+/* gcc exercise_2_7.c show_bytes.c -o exercise_2_7 */
+int main(void) {
+	const char *s = "abcdef";
+	show_bytes((byte_pointer) s, strlen(s) + 1);
+
+	return 0;
+}

chapters/chapter2/show_bytes.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "show_bytes.h"
+
+void show_bytes(byte_pointer start, size_t len) {
+	size_t i;
+	for(i = 0; i < len; i++) {
+		printf(" %.2x", start[i]);
+	}
+	printf("\n");
+}
+
+void show_int(int x) {
+	show_bytes((byte_pointer)&x, sizeof(int));
+}
+
+void show_float(float x) {
+	show_bytes((byte_pointer)&x, sizeof(float));
+}
+
+void show_pointer(void *x) {
+	show_bytes((byte_pointer)&x, sizeof(void*));
+}
+
+void test_show_bytes(int val) {
+	int ival = val;
+	float fval = (float)ival;
+	int *pval = &ival;
+	show_int(ival);
+	show_float(fval);
+	show_pointer(pval);
+}
+
+/*
+int main(void) {
+	test_show_bytes(0x01234567);
+
+	return 0;
+}
+*/

chapters/chapter2/show_bytes.h

@@ -0,0 +1,3 @@
+typedef unsigned char* byte_pointer;
+
+void show_bytes(byte_pointer start, size_t len);