void swap(int v[], int k) {
int temp;
temp = v[k];
v[k] = v[k+1];
v[k+1] = temp;
}
- v : $a0
- k : $a1
- temp : $t0
swap:
sll $t1, $a1, 2 # $t1 = k * 4
add $t1, $a0, $t1 # $t1 = v + (k * 4) = &v[k]
lw $t0, 0($t1) # temp = v[k]
lw $t2, 4($t1) # $t2 = v[k+1]
sw $t2, 0($t1) # v[k]= $t2
sw $t0, 4($t1) # v[k+1] = temp
jr $ra
void sort (int v[], int n) {
int i, j;
for (i = 0; i < n; i += 1) {
for (j = i – 1; j >= 0 && v[j] > v[j + 1]; j -= 1) {
swap(v, j);
}
}
}
- v : $a0
- n : $a1
- i : $s0
- j : $s1
sort:
addi $sp, $sp, -20
sw $ra, 16($sp)
sw $s3, 12($sp)
sw $s2, 8($sp)
sw $s1, 4($sp)
sw $s0, 0($sp)
move $s2, $a0 # $s2=v
move $s3, $a1 # $s3=n
move $s0, $zero # i=0
L1:
slt $t0, $s0, $s3 # i<n이면 $t0=1
beq $t0, $zero, Exit1 # i<n이 아니면 Exit1
addi $s1, s0, -1 # j=i-1
L2:
slt $t0, $s1, $zero # j<0이면 $t0=1
bne $t0, $zero, Exit2 # j<0이면 L1
sll $t1, $s1, 2 # $t1=j*4
add $t2, $s2, $t1 # $t2=&v[j]
lw $t3, 0($t2) # $t3=v[j]
lw $t4, 4($t2) # $t4=v[j+1]
slt $t0, $t4, $t3 # v[j+i]<v[j]이면 $t0=1
beq $t0, $zero, Exit2 # v[j+i]<v[j]아니면 L1
move $a0, $s2 # swap의 v=v
move $a1, $s1 # swap의 k=j
jal swap # swap 함수 호출
addi $s1, $s1, -1 # j -= 1
j L2 # L2로 이동
Exit2:
addi $s0, $s0, 1 # i += 1
j L1 # L1으로 이동
Exit1:
lw $s0, 0($sp)
lw $s1, 4($sp)
lw $s2, 8($sp)
lw $s3, 12($sp)
lw $ra, 16($sp)
addi $sp, $sp, 20
jr $ra
- callee : saved register
- caller : $ra 필수
