/* shift.c
 * For use in CSE351 Lec 5 on Integers
 *
 * Demonstrates the different effects of right and left shifting
 * in combination with signed and unsigned "8-bit" data.
 */
#include <stdio.h>


int main() {
	unsigned char x = 0x19;
	// shifts are bitwise operators,
	//   so data type doesn't matter until you interpret the data
	unsigned char L1 = x<<2;
	unsigned char L2 = x<<3;
	unsigned char L3 = x<<4;

	printf("\n");
	/* Note: printf statements can be hard to work with to view
                 small data.  The %d, %u, and %x specifiers extend
		 to 32 bits and %c displays characters instead of 
		 values.
        */
	printf("** Left Shift (<<) **\n");
	// %.2X prints at least 2 capital hex digits (padding with 0),
	//   using capital hex digits.
	printf("*      Hex: x = 0x%.2X, L1 = 0x%.2X, L2 = 0x%.2X, L3 = 0x%.2X\n",x,L1,L2,L3);
	// cast to signed char to get sign extension
	// %4 just means to pad to 4 characters in length
	printf("*   Signed: x = %4d, L1 = %4d, L2 = %4d, L3 = %4d\n",(char)x,(char)L1,(char)L2,(char)L3);
	printf("* Unsigned: x = %4u, L1 = %4u, L2 = %4u, L3 = %4u\n",x,L1,L2,L3);
	printf("*********************\n\n");


	unsigned char xu = 0xF0;
	char          xs = 0xF0;
	unsigned char R1u = xu>>3;
	char          R1s = xs>>3;
	unsigned char R2u = xu>>5;
	char          R2s = xs>>5;
	printf("** Right Shift (>>) **\n");
	printf("*    Logical: xu  = 0x%.2X = %4u\n",xu,xu);
	printf("*             R1u = 0x%.2X = %4u\n",R1u,R1u);
	printf("*             R2u = 0x%.2X = %4u\n",R2u,R2u);
	// cast to unsigned char to avoid sign extension for hex
	printf("* Arithmetic: xs  = 0x%.2X = %4d\n",(unsigned char)xs,xs);
	printf("*             R1s = 0x%.2X = %4d\n",(unsigned char)R1s,R1s);
	printf("*             R2s = 0x%.2X = %4d\n",(unsigned char)R2s,R2s);
	printf("**********************\n\n");

	
	// main function in C supposed to return an int
	//   (used to signal to OS)
	return 0;
}