我对MIPS很陌生，我正在做一个任务，要找到用户给定的2个数字之间的最大值，但是我遇到了两个错误，我不明白为什么，我写的代码从max开始：。谢谢你的帮助
错误1：第35行第9列：“$ra”：操作数的类型不正确
错误2：第40行第18列：“else”：操作数的类型不正确

.text
 main:
 li   $sp, 0x7ffffffc    # initialize $sp

# PROLOGUE
subu $sp, $sp, 8        # expand stack by 8 bytes
sw   $ra, 8($sp)        # push $ra (ret addr, 4 bytes)
sw   $fp, 4($sp)        # push $fp (4 bytes)
addu $fp, $sp, 8        # set $fp to saved $ra

li   $v0, 5             # read x into a0
syscall
move $a0, $v0

li   $v0, 5             # read y into a1
syscall
move $a1, $v0

# lw  $a1, arg0          # a1 = arg1
# lw    $a2, arg1
jal  max                 # v0 = max(arg0, arg1)

move $a0, $v0           # print_int(rval)
li   $v0, 1
syscall
li   $v0, 11            # print_char(\n)
li   $a0, 10
syscall

# EPILOGUE
move $sp, $fp           # restore $sp
lw   $ra, ($fp)         # restore saved $ra
lw   $fp, -4($sp)       # restore saved $fp
j    $ra                # return to kernel
max:
  #PROLOGUE
 # $a0 = x, $a1 = y
sle $a0, $a1, else  # if(x <= y), jump to else
move $t0, $a0       # if (x > y), x is max
else:   move $t0, $a1       # set $t0 = $t2, y is max