[TOC] ## 算术指令集 * 最多3个操作数 * 再说一遍，在这里，操作数只能是寄存器，绝对不允许出现地址 * 所有指令统一是32位 = 4 \* 8 bit = 4bytes = 1 word ``` add $t0,$t1,$t2 # $t0 = $t1 + $t2; add as signed (2's complement) integers sub $t2,$t3,$t4 # $t2 = $t3 Ð $t4 addi $t2,$t3, 5 # $t2 = $t3 + 5; "add immediate" (no sub immediate) addu $t1,$t6,$t7 # $t1 = $t6 + $t7; add as unsigned integers subu $t1,$t6,$t7 # $t1 = $t6 + $t7; subtract as unsigned integers mult $t3,$t4 # multiply 32-bit quantities in $t3 and $t4, and store 64-bit # result in special registers Lo and Hi: (Hi,Lo) = $t3 * $t4 　　　　　　　　　　　　　　　　# 运算结果存储在hi,lo（hi高位数据， lo地位数据） div $t5,$t6 # Lo = $t5 / $t6 (integer quotient) # Hi = $t5 mod $t6 (remainder) 　　　　　　　　　　　　　　　　# 商数存放在 lo, 余数存放在 hi mfhi $t0 # move quantity in special register Hi to $t0: $t0 = Hi 　　　　　　　　　　　　　　　　# 不能直接获取 hi 或 lo中的值， 需要mfhi, mflo指令传值给寄存器 mflo $t1 # move quantity in special register Lo to $t1: $t1 = Lo # used to get at result of product or quotient move $t2,$t3 # $t2 = $t3 ```