$4\mathrm{.}454\mathrm{.}45$

In Section $3\mathrm{.}4\mathrm{.}2$ the x$86-64$ pushq instruction was described as decrementing the stack pointer and then

storing the register at the stack pointer location. So$,$ if we had an instruction of the form pushq REG, for some

register REG, it would be equivalent to the code sequence

subq $$8,\%$rsp Decrement stack pointer

movq REG, $(\%$rsp$)$ Store REG on stack

A$.$ In light of analysis done in Practice Problem $4\mathrm{.}7.$ does this code sequence correctly describe

the behavior of the instruction pushq $\%$rsp$?$ Explain.

B$.$ How could you rewrite the code sequence so that it correctly describes both the cases where

REG is $\%$rsp as well as any other register? A$.$ Write and test a $C$ version that references the array elements with pointers, rather than using

array indexing.

B$.$ Write and test a Y$86-64$ program consisting of the function and test code. You may find it useful

to pattern your implementation after $86-64$ code generated by compiling your C code. Although

pointer comparisons are normally done using unsigned arithmetic, you can use signed arithmetic

for this exercise.

For this problem reflect back to your analysis done in Practice Problem $4\mathrm{.}7,$ does

this code sequence correctly describe the behavior of the instruction pushq $\%$rsp$?$

Explain. This will be done in a word document and then submitted to the

assignment.

$4\mathrm{.}47$

For this problem you will perform the following steps:

For Part A you will write a Y$86$ program that sorts an array of data using

Bubble Sort. The user should be allowed to input $10$ numbers from the

keyboard. You will sort the array in place $($i$.$e$.,$ no need to allocate

additional memory for the sorted array$).$ Follow the register usage

conventions outlined in the text. Your program should be a complete one.

Upload your $.$cpp source file to the assignment area.

For Part B$,$ Write and test a Y$86-64$ program consisting of the function

and test code. You may find it useful to pattern your implementation after

$x86-64$ code generated by compiling your C code. Although pointer

comparisons are normally done using unsigned arithmetic, you can use

signed arithmetic for this exercise.