Question

4. (20 pts) Write a 68K assembly program to evaluate the following expression for X 2 and Y=5. Also, write the final value of Z. Z (X3 + Y)/Y-X2) +X2 5. (20 pts) Explain in your own words what happens to the 68k stack when BSR and RTS instructions are executed. Given an example showing the stack

Answer 1

a)

.section    __TEXT, __text, regular, pure_instructions

.macosx_version_min 10, 12

.globl    _main

.align    4, 0x90

main:  

.cfi_startproc

## BB#0:

pushq    %rbp

Ltmp0:

    .cfi_def_cfa_offset 16

Ltmp1:

    .cfi_offset %rbp, -16

    movq    %rsp, %rbp

Ltmp2:

    .cfi_def_cfa_register %rbp

    subq    $16, %rsp

    leaq    L_.str(%rip), %rdi

    leaq    _s(%rip), %rsi

    movl    $2000, -4(%rbp)         ## imm = 0x7D0

    movl    $17, -8(%rbp)

    movl    -4(%rbp), %eax

    addl    -8(%rbp), %eax

    movl    %eax, %edx

    movb    $0, %al

    callq    _printf

    xorl    %edx, %edx

    movl    %eax, -12(%rbp)         ## 4-byte Spill

    movl    %edx, %eax

    addq    $16, %rsp

    popq    %rbp

    retq

    .cfi_endproc