MIPS汇编语言 - 调用一个函数，而无需使用“日航”​​的 [英] MIPS assembly language - Calling a funcion without the use of 'jal'

问题描述

我要调用一个函数，但由于某些原因，我现在允许使用
JAL 指令。有没有办法做到这一点？

I want to call a function but for some reasons I'm now allowed to use the jal instruction. Is there a way to do that?

这是我的想法是必须要以某种方式获取程序计数器的 $ RA 价值
然后只需使用Ĵ功能，所以像这样

An idea I had was to somehow get the value of the Program Counter in $ra and then just use j function, so something like this

                   # somehow $ra = address of next instruction
addi $ra, $ra, 8   # word length is 32 bytes so $ra gets the address of 
                   # the next instruction after 'j function'
j function
                   # continue here after function ends

function:
    # do stuff
    jr $ra

感谢

推荐答案

如果您查找任何引用 JAL 指令的行为，实在是小巫见大巫效仿。你可能知道，反正 JAL 在 $ RA 保存返回地址，这就是为什么你可以从函数中使用返回 JR $ RA 。因此，所有你需要做的是，解决自己的商店，那么你可以使用Ĵ。例如：

If you look up the behavior of the jal instruction in any reference, it is trivial to emulate it. You probably know it anyway that jal stores the return address in $ra, which is why you can return from functions using jr $ra. Thus, all you need to do is store that address yourself and then you can use j. For example:

    la $ra, continue
    j function
continue:
    ...

这篇关于MIPS汇编语言 - 调用一个函数，而无需使用“日航”​​的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！