Question

Take the following program and translate it into PEP/9 assembly language:

#include <iostream>

using namespace std;

int theArray[] = { 5, 11, -29, 45, 9, -1};

void sumPos(int ary[], int len, int &sum)

{

   sum = 0;

   for (int i = 0; i < len; i++)

           if (ary[i] > 0)

               sum = sum + ary[i];

}

int main()

{

   int total;

   sumPos(theArray, 6, total);

   for (int k=0; k < 6; k++)

     cout << theArray[k] << endl;

cout << "Positive sum is " << total << endl;

   return 0;

}

You must use equates to access the stack and the index register in accessing the array. Remember, the sumPos array does NOT know about the global "theArray" – the address of the array must be passed via the parameter.

For 10 points extra credit, make theArray a local array in main.

Submit source code.

Answer 1

.section __TEXT, __text, regular, pure_instructions

.macosx_version_min 10, 12

.globl _main

.align 4, 0x90

_main: ## @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

  

.section __DATA, __data

.globl _s ## @s

_s:

.asciz "GeeksforGeeks"

  

.section __TEXT, __cstring, cstring_literals

L_.str: ## @.str

.asciz "%s %d \n"

  

  

.subsections_via_symbols