MIPS assembly for a simple for loop

问题

I need to translate this C code to MIPS assembly. Here is the C code:

int tmp = 0; 
for (int  j = 0; j < 15; ++j) 
     tmp = tmp * 2 + 3

This is my MIPS assembly code. Is it a correct translation? If you see any mistakes I would really like to know.

# tmp = $v0
# j = $t0

.globl main

 main:
    li $v0,0

loop:
    bgt $t0,15,exit
    addi $t0,$t0,1
    mul $t1,$v0,2
    add $v0,$t1, 3
    j loop  

exit:

回答1:

Your loop goes from 0 to 14, so your bgt instruction should be: bgt $t0,14,exit I think.

.

回答2:

You don't set j ($t0) to zero before the loop.

回答3:

.data
mensage: asciiz "Text Test"
newline: asciiz "\n"
.text

# tmp = $v0
# j = $t0

main:
    li $t0,0
    li $t1,0
    li $t3,0
loop:
    bgt $t0,15,exit
    addi $t0,$t0,1
    j loop
    mul $t1,$t1,2
    add $t3,$t1,3  
exit:

li $v0,0
syscall

回答4:

I also don't know what MIPS simulator you're running, but I know some of them don't constants and they demand you assign those to registers. So like bgt Rsrc1, Src2, label, normally if you put an integer in src2 the computer will translate that but I know for some you'll get an error doing add $v0, $t1, 3 as it won't translate add into addi. Same with mul. I know my SPIM simulator doesn't allow it.

来源：https://stackoverflow.com/questions/9155336/mips-assembly-for-a-simple-for-loop