MIPS 汇编指令学习

MIPS 寄存器

MIPS comes with 32 general purpose registers named $0. . . $31
Registers also have symbolic names reflecting their conventional8 use:
$0  $zero constant 0
$1  $at used by assembler
$2  $v0 function result
$3  $v1 function result
$4  $a0 argument 1
$5  $a1 argument 2
$6  $a2 argument 3
$7  $a3 argument 4
$8  $t0 unsaved temporary
$9  $t1 unsaved temporary
$10 $t2 unsaved temporary
$11 $t3 unsaved temporary
$12 $t4 unsaved temporary
$13 $t5 unsaved temporary
$14 $t6 unsaved temporary
$15 $t7 unsaved temporary
$16 $s0 saved temporary
$17 $s1 saved temporary
$18 $s2 saved temporary
$19 $s3 saved temporary
$20 $s4 saved temporary
$21 $s5 saved temporary
$22 $s6 saved temporary
$23 $s7 saved temporary
$24 $t8 unsaved temporary
$25 $t9 unsaved temporary
$26 $k0 reserved for OS kernel
$27 $k1 reserved for OS kernel
$28 $gp pointer to global data
$29 $sp stack pointer
$30 $fp frame pointer
$31 $ra return address

寄存器号            符号名            用途
 0                 始终为0     看起来象浪费,其实很有用
 1                 at          保留给汇编器使用
 2-3               v0,v1       函数返回值
 4-7               a0-a3       前头几个函数参数
 8-15              t0-t7       临时寄存器,子过程可以不保存就使用
 24-25             t8,t9       同上
 16-23             s0-s7       寄存器变量,子过程要使用它必须先保存
                               然后在退出前恢复以保留调用者需要的值
 26,27             k0,k1       保留给异常处理函数使用
 28                gp          global pointer;用于方便存取全局或者静态变量
 29                sp          stack pointer
 30                s8/fp       第9个寄存器变量;子过程可以用它做frame pointer
 31                 ra         返回地址
硬件上这些寄存器并没有区别(除了0号),区分的目的是为了不同的编译器产生的代码可以通用

MIPS 指令集（共31条）