MIPS: Summary After Procedures

Arithmetic Instructions

Name	Syntax	Meaning
add	add $rd, $rs, $rt	$rd = $rs + $rt
addu	addu $rd, $rs, $rt	$rd = $rs + $rt (unsigned)
sub	sub $rd, $rs, $rt	$rd = $rs - $rt
subu	subu $rd, $rs, $rt	$rd = $rs - $rt (unsigned)
addi	addi $rd, $rs, constantValue	$rd = $rs + constantValue
addiu	addiu $rd, $rs, constantValue	$rd = $rs + constantValue (unsigned)

Logical Instructions (so far)

Name	Syntax	Meaning
sll (shift left logical)	sll $rd, $rs, shiftAmount	shift $rd by shiftAmount, put in $rd
srl (shift right logical)	srl $rd, $rs, shiftAmount	shift $rd by shiftAmount, put in $rd

Memory Access Instructions (so far)

Name	Syntax	Meaning
lw (load word)	lw $rd, offset($base)	load word from address ($base+offset) to $rd
sw (store word)	sw $rs, offset($base)	store word from $rs to address ($base+offset)

Branch-Related Instructions (so far)

Name	Syntax	Meaning
beq (branch on equal)	beq $rs, $rt, label	branch to label if $rs == $rt
bne (branch on not equal)	bne $rs, $rt, label	branch to label if $rs != $rt
slt (set on less than)	slt $rd, $rs, $rt	set $rd to 1 if $rs < $rt
sltu (set on less than)	sltu $rd, $rs, $rt	set $rd to 1 if $rs < $rt (unsigned)

Jump Instructions

Name	Syntax	Meaning
jr	jr $ra	jump to the address in $ra
j	j label	jump to the address associated with label
jal	jal label	store the program counter (PC) in $ra and then jump to the address associated with label

Registers (so far)

Number	Name	Comments
0	$zero	constant 0
...
2 3	$v0   $v1	results of a function (not preserved across function call) results of a function
4 5 6 7	$a0   $a1   $a2   $a3	argument 1 (not preserved across function call) argument 2 argument 3 argument 4
8 . . . 15	$t0 . . . $t7	temporary (not preserved across function call) . . . temporary (not preserved across function call)
16 . . . 23	$s0 . . . $s7	saved temporary (preserved across function call) . . . saved temporary (preserved across function call)
24 25	$t8 $t9	temporary (not preserved across function call) temporary (not preserved across function call)
...
29 30 31	$sp   $fp   $ra	stack pointer frame pointer return address (set by jal, not preserved)

There is also special PC register, to which programmers do not have direct access.