CS220  Homework 5 Due March 11, 2016

Name:

1. Consider the following C code...

	char * myfn(char * in) {
		char out[80];
		int i;
		for(i=0; in[i]!=0 && i < 80; i++ ) {
			out[i]=in[i] | 0x20;
		}
		return out;
	}
	
    Will this code work without error?  If not, what is the problem?
     
2. Assuming full data alignment is enforced, how many bytes are required for the following
   C structure?
   
   struct {
   	int width;
   	int height;
   	int depth;
   	short shapeID;
   } shapeA;
   
3. Suppose you have a binary tree made up of nodes as follows...

	struct tnode {
		int value;
		struct tnode * left;
		struct tnode * right;
	}
	
    And a program has created a tree in which every left node has a value less than its parent value, and 
    every right node has a value greater than its parent value.
    
    Consider the following code:
    
    void prPost(struct tnode *root) {
    	if (root->right) prPost(root->right);
    	printf("Value: %d\n",root->value;
    	if (root->left) prPost(root->left);
    }
    
    What would be true about the order of the values printed by this program?
    
4. Are the following statements about Instruction Set Architectures True or False:

	a. ____ Machines that support an ISA provide a hardware interface that implements that ISA
	
	b. ____ Any machine that supports x86-32 also supports x86-16.	
	
	c. ____ A machine can only support a single family of ISA's, where x and y are in the same family
		if x is downward compatible with y.

	d. ____ Many different machines support the x86-32 ISA.

	e. ____ An operating system which runs on the x86-32 ISA cannot run on a machine that
	        does not support the x86-32 ISA
	        
5. 	Given the following register and memory values...

		Reg	| Value			Address		| Value
		--------+-----------	        ----------------+------------
		eax	| x0000 0003		xCA00 01D4	| xFFFF FFFF
		ebx	| x0000 004A		xCA00 01D0	| x0000 0000
		...	| ...			xCA00 01CC	| x0000 0064
		ebp	| xCA00 01C0		xCA00 01C8	| x0000 00C8
		esp	| xCA00 01BC		xCA00 01C4	| xB32C 302A
						xCA00 01C0	| xCA00 0208
						xCA00 01BC	| x0300 0000
						
	What will be in the eax register after the execution of each instruction below...
	
	a. 	movl  8(%ebp),%eax
	
	b. 	addl  12(%ebp),%eax
	
	c. 	shrl  $2,eax