chap-04: Add demos with signed-unsigned operations

Signed-off-by: Razvan Deaconescu <razvan.deaconescu@cs.pub.ro>

curs/chap-04-reprezentare/07-signed-unsigned-ops/.gitignore

@@ -0,0 +1,4 @@
+/cast_op_precedence
+/negative_overflow
+/signed_unsigned_print
+/signed_unsigned_char_int

curs/chap-04-reprezentare/07-signed-unsigned-ops/Makefile

@@ -0,0 +1,15 @@
+CFLAGS = -m32 -fno-PIC -Wall
+LDFLAGS = -m32 -no-pie
+BINARIES = cast_op_precedence signed_unsigned_char_int signed_unsigned_print negative_overflow
+
+.PHONY: all clean
+
+all: $(BINARIES)
+
+$(BINARIES): %: %.o
+
+: %.o: %.c
+
+clean:
+	-rm -f *~
+	-rm -f $(BINARIES) $(BINARIES:=.o)

curs/chap-04-reprezentare/07-signed-unsigned-ops/cast_op_precedence.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+
+int main(void)
+{
+	signed int a;
+	signed int b;
+	signed int c;
+	signed int d;
+	signed char c1 = 100;
+	signed char c2 = 100;
+	signed char c3;
+	signed char c4 = 127;
+	signed char c5 = 127;
+	signed char c6;
+
+	c3 = c1 + c2;
+	a = c3;
+	b = c1 + c2;
+
+	printf("a: 0x%08x\n", a);
+	printf("b: 0x%08x\n", b);
+
+	c6 = ++c4;
+	c = c6;
+	d = ++c5;
+
+	printf("c: 0x%08x\n", c);
+	printf("d: 0x%08x\n", d);
+
+	return 0;
+}

curs/chap-04-reprezentare/07-signed-unsigned-ops/negative_overflow.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int main(void)
+{
+	signed char c = -120;
+	unsigned char cu = c;
+
+	printf("0x%02x\n", c);
+	printf("0x%02x\n", cu);
+
+	return 0;
+}

curs/chap-04-reprezentare/07-signed-unsigned-ops/signed_unsigned_char_int.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+
+int main(void)
+{
+	signed char c1 = -9;
+	unsigned char c2 = c1;
+	signed int i1;
+	unsigned int i2;
+
+	i1 = c1;
+	printf("0x%08x\n", i1);
+	i1 = c2;
+	printf("0x%08x\n", i1);
+	i1 = c1 + c2;
+	printf("0x%08x\n", i1);
+
+	i2 = c1;
+	printf("0x%08x\n", i2);
+	i2 = c2;
+	printf("0x%08x\n", i2);
+	i2 = c1 + c2;
+	printf("0x%08x\n", i2);
+
+	i1 = -9;
+	i2 = i1;
+
+	c1 = i1;
+	printf("0x%02x\n", c1);
+	c1 = i2;
+	printf("0x%02x\n", c1);
+
+	c2 = i1;
+	printf("0x%02x\n", c2);
+	c2 = i2;
+	printf("0x%02x\n", c2);
+
+	return 0;
+}

curs/chap-04-reprezentare/07-signed-unsigned-ops/signed_unsigned_print.c

@@ -0,0 +1,35 @@
+#include <stdio.h>
+
+int v1 = -1;
+unsigned int v2 = -2;
+
+int sum1;
+unsigned int sum2;
+
+int main(void)
+{
+	printf("v1 (%%d): %d, v1 (%%u): %u, v1 (%%08x): 0x:%08x\n", v1, v1, v1);
+	printf("v2 (%%d): %d, v2 (%%u): %u, v2 (%%08x): 0x:%08x\n", v2, v2, v2);
+	printf("-1 (%%d): %d, -1 (%%u): %u, -1 (%%08x): 0x:%08x\n", -1, -1, -1);
+
+	sum1 = v1 + 20;
+	sum2 = v2 + 20;
+
+	printf("sum1 (%%d): %d, sum1 (%%u): %u, sum1 (%%08x): 0x:%08x\n", sum1, sum1, sum1);
+	printf("sum2 (%%d): %d, sum2 (%%u): %u, sum2 (%%08x): 0x:%08x\n", sum2, sum2, sum2);
+
+	// MAXINT MAXINT-1
+	if (v1 < v2)
+		printf("-1 < -2\n");
+	else
+		printf("-1 > -2\n");
+
+	//10      MAXINT-1
+	v1 = 10;
+	if (v1 < v2)
+		printf("10 < -2\n");
+	else
+		printf("10 > -2\n");
+
+	return 0;
+}