CSC231 Homework 11 2012

--D. Thiebaut 13:14, 28 November 2012 (EST)

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Problem #1

This is a continuation of the first problem of Homework 8. Here you need to complete the output of the dumpRegs function so that it outputs all the registers in decimal, both in unsigned and in signed format.

Here's an example of the output of your program showing how to shows the contents of each register in hexadecimal, as an unsigned it, and as a signed int.

-------------------------------------
eax = 0x00000004  4 4
ebx = 0x00000001  1 1
ecx = 0xFFFFFFFF  4294966272 -1
edx = 0x000012FC  4860 4860
edi = 0xFFFFFFFE  4294966271 -2 
esi = 0x12235557  304305495 304305495
-------------------------------------

Requirements

• Figure out how to print negative integers.
• In the header of the program you will submit, indicate how much stack space is used as a function of the number you are printing. Express your answer as precisely as possible, and in bytes.
• You need to store your dumpRegs function and all its accompanying functions in a separate file called dumpRegs.ing
• Your printDecimal function must be recursive. The one we saw in class isn't.
• Your main program (you won't be submitting it) will look something like this (notice that I am using numbers that are positive and negative in 2's complement format):

;;; your header

%include "dumpRegs.inc"

		section	.data
;;; your data

		section	.text
		global	_start
 
_start:
 
;;; Initialize the registers
		mov	eax, 0x12345678
		mov	ebx, 0x55FF55FF
		mov	ecx, 0xFEDCBA98
		mov	edx, 0x00000000
		mov	esi, 0xFFFFFFFF
		mov	edi, 0xFFFFFFF0
 
;;; dump them twice to verify that no registers gets modified...
	        call    dumpRegs
		call	dumpRegs
 
 
;;; exit back to OS
		mov	ebx, 0
		mov	eax, 1
		int	0x80

Optional and Extra-Credits

• 0.3 extra points: make your print decimal function output the decimal with commas separating each group of 3 digits. For example, it will display 123456789 as 123,456,789. Similarly, it will display -25668 as -25,668, and -34 as -34. For this version of the program, the printDecimal function does not need to be recursive.

• 0.6 extra points: same requirement as above, except that the printDecimal unction has to be recursive.

Submission

Submit only dumpRegs.inc. I will provide my own main program that will use just this line to include your program:

%include "dumpRegs.inc"

The submit command is:

 rsubmit hw11 dumpRegs.inc

Problem #2

What is the maximum amount of stack space (in bytes) required by the program of Problem 2 of Homework 10?

Store your answer in a text file called hw11b.txt and submit it as follows:

rsubmit hw11 hw11b.txt