MIPS寄存器和指令总结

每次学计组的时候总要去查MIPS的寄存器和指令，索性自己总结了如下的知识点，方便之后查看

32个通用寄存器

Register	Name	Usage
$0	$zero	常量0(constant value 0)
$1	$at	保留给汇编器(Reserved for assembler)
$2-$3	$v0-$v1	函数调用返回值(values for results and expression evaluation)
$4-$7	$a0-$a3	函数调用参数(arguments)
$8-$15	$t0-$t7	暂时的(或随便用的)
$16-$23	$s0-$s7	保存的(或如果用，需要SAVE/RESTORE的)(saved)
$24-$25	$t8-$t9	暂时的(或随便用的)
$28	$gp	全局指针(Global Pointer)
$29	$sp	堆栈指针(Stack Pointer)
$30	$fp	帧指针(Frame Pointer)
$31	$ra	返回地址(return address)

32个寄存器（详细）

Register Name	Number	Usage
$zero	0	Constant 0
$at	1	Reserved for assembler
$v0	2	Expression evaluation and results of a function
$v1	3	Expression evaluation and results of a function
$a0	4	Argument 1
$a1	5	Argument 2
$a2	6	Argument 3
$a3	7	Argument 4
$t0	8	Temporary (not preserved across call)
$t1	9	Temporary (not preserved across call)
$t2	10	Temporary (not preserved across call)
$t3	11	Temporary (not preserved across call)
$t4	12	Temporary (not preserved across call)
$t5	13	Temporary (not preserved across call)
$t6	14	Temporary (not preserved across call)
$t7	15	Temporary (not preserved across call)
$s0	16	Saved temporary (preserved across call)
$s1	17	Saved temporary (preserved across call)
$s2	18	Saved temporary (preserved across call)
$s3	19	Saved temporary (preserved across call)
$s4	20	Saved temporary (preserved across call)
$s5	21	Saved temporary (preserved across call)
$s6	22	Saved temporary (preserved across call)
$s7	23	Saved temporary (preserved across call)
$t8	24	Temporary (not preserved across call)
$t9	25	Temporary (not preserved across call)
$k0	26	Reserved for OS kernel
$k1	27	Reserved for OS kernel
$gp	28	Pointer to global area
$sp	29	Stack pointer
$fp or s8	30	Frame pointer
$ra	31	Return address (used by function call)

MIPS指令集（31条）

助记符	用法	解释	注释
R-type
add	add $1,$2,$3	$1=$2+$3	其中rs＝$2，rt=$3, rd=$1
addu	addu $1,$2,$3	$1=$2+$3	其中rs＝$2，rt=$3, rd=$1,无符号数
sub	sub $1,$2,$3	$1=$2-$3	其中rs＝$2，rt=$3, rd=$1
subu	subu $1,$2,$3	$1=$2-$3	其中rs＝$2，rt=$3, rd=$1,无符号数
and	and $1,$2,$3	$1=$2 & $3	其中rs＝$2，rt=$3, rd=$1
or	or $1,$2,$3	$1=$2 | $3	其中rs＝$2，rt=$3, rd=$1
xor	xor $1,$2,$3	$1=$2 ^ $3	其中rs＝$2，rt=$3, rd=$1(异或）
nor	nor $1,$2,$3	$1=~($2|$3)	；其中rs＝$2，rt=$3, rd=$1(或非）
slt	slt $1,$2,$3	if($2<$3) $1=1 else $1=0	if (rs < rt) rd=1 else rd=0 ；其中rs＝$2，rt=$3, rd=$1
sltu	sltu $1,$2,$3	if($2<$3) $1=1 else $1=0	if (rs < rt) rd=1 else rd=0 ；其中rs＝$2，rt=$3, rd=$1 (无符号数）
sll	sll $1,$2,10	$1=$2<<10	rd <- rt << shamt ；shamt存放移位的位数， 也就是指令中的立即数，其中rt=$2, rd=$1
srl	srl $1,$2,10	$1=$2>>10	rd <- rt >> shamt ；(logical) ，其中rt=$2, rd=$1
sra	sra $1,$2,10	$1=$2>>10	rd <- rt >> shamt ；(arithmetic) 注意符号位保留 其中rt=$2, rd=$1
sllv	sllv $1,$2,$3	$1=$2<<$3	rd <- rt << rs ；其中rs＝$3，rt=$2, rd=$1
srlv	srlv $1,$2,$3	$1=$2>>$3	rd <- rt >> rs ；(logical)其中rs＝$3，rt=$2, rd=$1
srav	srav $1,$2,$3	$1=$2>>$3	rd <- rt >> rs ；(arithmetic) 注意符号位保留 其中rs＝$3，rt=$2, rd=$1
jr	jr $31	goto $31	PC <- rs
I-type
addi	addi $1,$2,100	$1=$2+100	rt <- rs + (sign-extend)immediate ；其中rt=$1,rs=$2
addiu	addiu $1,$2,100	$1=$2+100	rt <- rs + (zero-extend)immediate ；其中rt=$1,rs=$2
andi	andi $1,$2,10	$1=$2 & 10	rt <- rs & (zero-extend)immediate ；其中rt=$1,rs=$2
ori	andi $1,$2,10	$1=$2 | 10	rt <- rs | (zero-extend)immediate ；其中rt=$1,rs=$2
xori	andi $1,$2,10	$1=$2 ^ 10	rt <- rs xor (zero-extend)immediate ；其中rt=$1,rs=$2
lui	lui $1,100	$1=100*65536	rt <- immediate*65536 ；将16位立即数放到目标寄存器高16 位，目标寄存器的低16位填0
lw	lw $1,10($2)	$1=memory[$2 +10]	rt <- memory[rs + (sign-extend)immediate] ；rt=$1,rs=$2
sw	sw $1,10($2)	memory[$2+10] =$1	memory[rs + (sign-extend)immediate] <- rt ；rt=$1,rs=$2
beq	beq $1,$2,10	if($1==$2) goto PC+4+40	if (rs == rt) PC <- PC+4 + (sign-extend)immediate<<2
bne	bne $1,$2,10	if($1!=$2) goto PC+4+40	if (rs != rt) PC <- PC+4 + (sign-extend)immediate<<2
slti	slti $1,$2,10	if($2<10) $1=1 else $1=0	if (rs <(sign-extend)immediate) rt=1 else rt=0 ； 其中rs＝$2，rt=$1
sltiu	sltiu $1,$2,10	if($2<10) $1=1 else $1=0	if (rs <(zero-extend)immediate) rt=1 else rt=0 ； 其中rs＝$2，rt=$1
J-type
j	j 10000	goto 10000	PC <- (PC+4)[31…28],address,0,0 ；address=10000/4
jal	jal 10000	$31<-PC+4; goto 10000	$31<-PC+4；PC <- (PC+4)[31…28],address,0,0 ；address=10000/4

其他指令

助记符	用法	解释	注释
bnez	bnez $t0 ,trylk	if $t0 != 0 ,goto trylk
beqz	beqz $t0 ,trylk	if $t0 ==0, goto trylk
伪指令
not	not $1,$2	对应MIPS，nor $1, $2,$zero	或非操作
move	move $1,$2	对应MIPS , or $1, $2,$zero
li	li $1,$2	对应MIPS，ori $1,$zero,c	c为16位立即数

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