main:
li $a0,4
li $a1,0
jal nchoosek # evaluate C(4,0); should be 1
jal printv0
li $a0,4
li $a1,1
jal nchoosek # evaluate C(4,1); should be 4
jal printv0
li $a0,4
li $a1,2
jal nchoosek # evaluate C(4,2); should be 6
jal printv0
li $a0,4
li $a1,3
jal nchoosek # evaluate C(4,3); should be 4
jal printv0
li $a0,4
li $a1,4
jal nchoosek # evaluate C(4,4); should be 1
jal printv0
li $a0,4
li $a1,5
jal nchoosek # evaluate C(4,5); should be 0
jal printv0
li $v0,10
syscall
nchoosek: # you fill in the prologue
beq $a1,$0,return1
beq $a0,$a1,return1
beq $a0,$0,return0
blt $a0,$a1,return0
addi $a0,$a0,-1 # C(n,k) = C(n-1,k) + C(n-1,k-1)
move $s0,$a0
move $s1,$a1
jal nchoosek
move $s2,$v0
move $a0,$s0
addi $a1,$s1,-1
jal nchoosek
add $v0,$v0,$s2
j return
return0:
move $v0,$0
j return
return1:
addi $v0,$0,1
return: # you fill in the epilog
printv0:
addi $sp,$sp,-4
sw $ra,0($sp)
move $a0,$v0
li $v0,1
syscall
li $a0,'\n'
li $v0,11
syscall
lw $ra,0($sp)
addi $sp,$sp,4
jr $ra
题目要求补足这段代码,原谅我mips渣渣,求大神来补充