UNIT 1 - ADDRESSING MODES

1. ADDRESSING MODES
Mr. C.KARTHIKEYAN,
ASSISTANT PROFESSOR,
ECE , RMKCET

2. MIPS ADDRESSING MODES
Immediate Addressing Mode
Register Addressing Mode
Base or Displacement Addressing Mode
PC-Relative Addressing Mode
Pseudo Direct Addressing Mode

3. Immediate Addressing Mode
Eg:1. addi $s0, $zero,7
Eg:4. ori $t0,$t1,8
$s0 = 0 + 7
$t0 = $t1 | 8

4. Register Addressing Mode
Eg:1. add $s1,$s2,$s3
Eg:2. or $t0,$t1,$t2
Eg:3. srl $s7,$s0,4
$s1 = $s2 + $s3
$t0 = $t1 | $t2
$s7 = $s0 >> 4

5. Base / Displacement Addressing Mode
Eg:1. lw $s1, 4($s2)
Eg:2. sw $s0, 8($s4)
$s1 = Mem [$s2+4]
Mem [$s4+8] = $s0

6. PC – Relative Addressing Mode
Eg:1. beq $s1, $s2, 25
Eg:2. bne $s0, $s1, 20
if($s1==$s2) goto PC+4+100
if($s0!=$s1) goto PC+4+80

7. Pseudo Direct Addressing Mode
Eg:1. j 2500
Eg:2. jr $ra
Eg:3. jal 2500
go to 10000
goto $ra
$ra=PC+4 goto 10000

8. EXAMPLE
Loop: add $t1,$s3,$s3
add $t1,$t1,$t1
add $t1,$t1,$s6
lw $t0,0($t1)
bne $t0,$s5,Exit
add $s3,$s3,$s4
j loop
Exit:
35 9 8 0
0 19 19 9 0 32
5 8 21 2
2 2000
8000
8004
8008
0 9 9 9 0 32
0 9 22 9 0 32
0 19 20 19 0 32
8012
8016
8020
8024
8028
Starting address 8000

9. 0000 0000 0001 0000 0101 0001 0000 0000
0000 0000 0001 0000 0101 0001 0000 0000
00000000000100000101000100000000
000000 00000100000101000100000000
R - Type
000000 00000100000101000100 000000
sll
000000 00000 10000 01010 00100 000000
sll $t2,
op rs rt rd Shift amt fn
$s0, 4
0x00105100 00105100 hex