我在使用以下mips代码时遇到了一些问题:
li $t0, -1
li $t5, 0
countNumberofVariables:
addi $t0, $t0, 1
beq $t0, $t8, endCount
add $t1, $t0, $t9
lb $t1, ($t1)
li $t2, 10
beq $t1, $t2, endCount
li $t2, 13
beq $t1, $t2, endCount
li $t2, 97
blt $t1, $t2, countNumberofVariables
li $t2, 122
bgt $t1, $t2, countNumberofVariables
li $t2, -1
stackScan:
addi $t2, $t2, 2
add $t3, $sp, $t2
lb $t3, ($t3)
beq $t3, $t1, countNumberOfVariables
li $t4, 64
bne $t4, $t3, stackScan
addi $sp, $sp, -2
sb $t1, ($sp)
li $t1, 0
sb $t1, 1($sp)
addi $t5,$t5,1
j countNumberofVariables
endCount:
move $a0, $t5
li $v0, 1
syscall
j main
我要做的是计算字符串中唯一的小写字母数($ t9中的地址,$ t8中的长度)。我遇到的问题是,当在SPIM 7.3下运行时,我得到了这个错误:
Instruction references undefined symbol at 0x00400108
[0x00400108] 0x11180000 beq $8, $24, 0 [endCount-0x00400108]; 87: beq $t0, $t8, endCount
变量是:
$t0, outer loop counter
$t5, number of unique lowercase letters in string
$t1, the character at the current location in the string
$t2, random variable in outer loop, loop counter in inner loop
$t3, the character at the current location on the stack in the inner loop
$t4, random variable
请注意,魔术常量64是堆栈顶部的标记值。
编辑:已解决。我将标签名称更改为更短,这似乎满足了spim。不太确定底层问题是什么,但是如果你遇到的问题似乎不应该有问题,那就改成更短的标签