Question

uestion 2

Transform the following “C” program into assembly for the 6808 Microcontroller.



Remember when converting this “C” code to follow

best practices

covered in DEF in terms of implementing subroutines in assembly

o

This means that parameters are passed on the stack to subroutines

o

Return values are passed back on the stack

o

You clean up the stack after every use (every subroutine call) to prepare it for the next call

Keep in mind that once your translated this program into assembly – you can step through it to ensure that it behaves correctly and calculates the

expected results.

/* -------------------------------------------------------------

PURPOSE: This program will take 2 operand values and

calculate the sum and difference of the values

------------------------------------------------------------- */

// This function calculates the sum of 2 operands called "A" and "B"

Int

calculateSum(

int

A,

int

B)

{

return

(A + B);

}

// This function calculates the difference between 2 operands by negating B and adding it to A

int

calculateDifference(

int

A,

int

B)

{

return

(calculateSum(A, -B));

// reuse the calculateSum function

}

void

main(

void

)

{

int

firstOperand = 18;

// to be stored at address $80 within the 6808

int

secondOperand = 8;

// to be stored at address $81 within the 6808

int

sum = 0;

// to be stored at address $84 within the 6808

int

difference = 0;

// to be stored at address $86 within the 6808

// call the calculateSum function in order to calculate the total and store it in the "sum" variable

sum = calculateSum(firstOperand, secondOperand);

// call the calculateDifference function in order to calculate the difference and store it in the "difference"

}

please help I need the code in assembly

Answer 1

.Ltext0:  .globl calculateSum calculateSum: 

 .LFB0: 

 .cfi_startproc 0000 55  pushq %rbp  .cfi_def_cfa_offset 16  .cfi_offset 6, -16 0001 4889E5  movq %rsp, %rbp  .cfi_def_cfa_register 6 0004 897DFC  movl %edi, -4(%rbp) 0007 8975F8  movl %esi, -8(%rbp) 

000a 8B55FC  movl -4(%rbp), %edx 000d 8B45F8  movl -8(%rbp), %eax 0010 01D0  addl %edx, %eax 

0012 5D  popq %rbp  .cfi_def_cfa 7, 8 0013 C3  ret  .cfi_endproc 

 .LFE0: 

 .globl calculateDifference calculateDifference: 

 .LFB1: 

 .cfi_startproc 0014 55  pushq %rbp  .cfi_def_cfa_offset 16  .cfi_offset 6, -16 0015 4889E5  movq %rsp, %rbp  .cfi_def_cfa_register 6 0018 4883EC08  subq $8, %rsp 001c 897DFC  movl %edi, -4(%rbp) 001f 8975F8  movl %esi, -8(%rbp) 

0022 8B45F8  movl -8(%rbp), %eax 0025 F7D8  negl %eax 0027 89C2  movl %eax, %edx 0029 8B45FC  movl -4(%rbp), %eax 002c 89D6  movl %edx, %esi 002e 89C7  movl %eax, %edi 0030 E8000000  call calculateSum 00 

0035 C9  leave  .cfi_def_cfa 7, 8 0036 C3  ret  .cfi_endproc 

 .LFE1: 

  .globl main main: 

 .LFB2: 

 .cfi_startproc 0037 55  pushq %rbp  .cfi_def_cfa_offset 16  .cfi_offset 6, -16 0038 4889E5  movq %rsp, %rbp  .cfi_def_cfa_register 6 003b 4883EC10  subq $16, %rsp 

003f C745F012  movl $18, -16(%rbp) 000000 

0046 C745F408  movl $8, -12(%rbp) 000000 

004d C745F800  movl $0, -8(%rbp) 000000 

0054 C745FC00  movl $0, -4(%rbp) 000000 

005b 8B55F4  movl -12(%rbp), %edx 005e 8B45F0  movl -16(%rbp), %eax 0061 89D6  movl %edx, %esi 0063 89C7  movl %eax, %edi 0065 E8000000  call calculateSum 00 006a 8945F8  movl %eax, -8(%rbp) 

006d 8B55F4  movl -12(%rbp), %edx 0070 8B45F0  movl -16(%rbp), %eax 0073 89D6  movl %edx, %esi 0075 89C7  movl %eax, %edi 0077 E8000000  call calculateDifference 00 007c 8945FC  movl %eax, -4(%rbp) 

007f 90  nop 0080 C9  leave  .cfi_def_cfa 7, 8 0081 C3  ret  .cfi_endproc 

 .LFE2: 

 .Letext0: