Assembly language LC2200 write an assembly language program equivalent to the fo

Question

Assembly language LC2200

write an assembly language program equivalent to the following:

a = 0;

for (int i = 0; i < d; i++)

{

if (c != d)

a += b + (c - d) + b;

else if (c == b)

a += c + c + c + c;

else

a += (b + b) - (c + c);

}

where:

• a is located in $fp + 1

• b is located in $fp + 2

• c is located in $fp + 3

• d is located in $fp + 4

Values should be read in from memory to start with and a should be written to memory when done. You can reorder

operations as long as they produce the same result as the statement above. You should be able to run this assembly file with

different data files.

The variable i can be located in a variable or just kept in a register, whichever you prefer. This code expects that d > 0.

Inside for loop:

lw $t0, $fp, 2
lw $t1, $fp, 3
lw $t2, $fp, 4
beq $t0, $t1, cbequal

nand $t2, $t2, $t2
addi $t2, $t2, 1 #convert $t2 for negative
add $t1, $t2, $t1 #c-d = t1
add $t0, $t0, $t0
add $t0, $t1, $t0
lw $t2, $fp,1
add $t2, $t0, $t2
sw $t2, $fp, 1
halt

cbequal: beq $t1, $t2, equal

add $t0, $t0, $t0
add $t1 ,$t1, $t1
nand $t1 ,$t1, $t1
addi $t1, $t1, 1
add $t0, $t0, $t1
lw $t1, $fp, 1
add $t1, $t1, $t0
sw $t1, $fp, 1
halt

equal:add $t0, $t1, $t1
add $t0, $t1, $t0
add $t0, $t1, $t0
lw $t2, $fp, 1
add $t0, $t0, $t2
sw $t0, $fp, 1
halt

And tomake for loop work I have to use jalr, but I have no clue how to make for loop work...

Thank you in advance.

Explanation / Answer

main:
        push    rbp
        mov     rbp, rsp
        mov     DWORD PTR [rbp-4], 0
        mov     DWORD PTR [rbp-8], 0
.L6:
        mov     eax, DWORD PTR [rbp-8]
        cmp     eax, DWORD PTR [rbp-12]
        jge     .L2
        mov     eax, DWORD PTR [rbp-16]
        cmp     eax, DWORD PTR [rbp-12]
        je      .L3
        mov     eax, DWORD PTR [rbp-16]
        sub     eax, DWORD PTR [rbp-12]
        mov     edx, eax
        mov     eax, DWORD PTR [rbp-20]
        add     edx, eax
        mov     eax, DWORD PTR [rbp-20]
        add     eax, edx
        add     DWORD PTR [rbp-4], eax
        jmp     .L4
.L3:
        mov     eax, DWORD PTR [rbp-16]
        cmp     eax, DWORD PTR [rbp-20]
        jne     .L5
        mov     eax, DWORD PTR [rbp-16]
        lea     edx, [rax+rax]
        mov     eax, DWORD PTR [rbp-16]
        add     edx, eax
        mov     eax, DWORD PTR [rbp-16]
        add     eax, edx
        add     DWORD PTR [rbp-4], eax
        jmp     .L4
.L5:
        mov     eax, DWORD PTR [rbp-20]
        lea     edx, [rax+rax]
        mov     eax, DWORD PTR [rbp-16]
        add     eax, eax
        sub     edx, eax
        mov     eax, edx
        add     DWORD PTR [rbp-4], eax
.L4:
        add     DWORD PTR [rbp-8], 1
        jmp     .L6
.L2:
        mov     eax, 0
        pop     rbp
        ret

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