Unit i ca- mips addressing

Unit i CA- MIPS Addressing

1. A.S.Prabaharan AP/CSE
UNIT I MIPS Addressing

2. Addressing in Branches and Jumps
The MIPS jump instructions have the simplest addressing.
They use the final MIPS instruction format, called the J-type,
which consists of 6 bits for the operation field and the rest of the
bits for the address field .
j 10000 # go to location 10000



where the value of the jump opcode is 2 and the jump address is
10000.

3. Unlike the jump instruction, the conditional branch instruction
must specify two operands in addition to the branch address.
bne $s0,$s1,Exit # go to Exit if $s0 ≠ $s1



branch instruction would calculate the following:
Program counter Register Branch address
PC-relative addressing

4. Showing Branch Offset in Machine Language
The while loop as compiled into this MIPS assembler code:
Loop:sll $t1,$s3,2 # Temp reg $t1 = 4 * i
 add $t1,$t1,$s6 # $t1 = address of save[i]
 lw $t0,0($t1) # Temp reg $t0 = save[i ]
 bne $t0,$s5, Exit # go to Exit if save[i ] ≠ k
 addi $s3,$s3,1 # i = i + 1
 j Loop # go to Loop
Exit:

5. If we assume we place the loop starting at location 80000 in
memory, what is the MIPS machine code for this loop?
The assembled instructions and their addresses are:

6. MIPS Addressing Mode
Addressing mode One of several addressing regimes delimited by
their varied use of operands and/or addresses.
1. Immediate addressing, where the operand is a constant within
the instruction itself
2. Register addressing, where the operand is a register
3. Base or displacement addressing, where the operand is at the
memory location whose address is the sum of a register and a
constant in the instruction
4. PC-relative addressing, where the branch address is the sum of
the PC and a constant in the instruction
5. Pseudo direct addressing, where the jump address is the 26
bits of the instruction concatenated with the upper bits of the PC

10. What is the Addressing Mode
Add $s0,$s1,5


A. Register addressing
B. Immediate addressing
C. Base addressing
D. PC-relative addressing

Ans:B

11. What is the Addressing Mode
Add $s0,$s1,$s2


A. Register addressing
B. Immediate addressing
C. Base addressing
D. PC-relative addressing
Ans:A

12. What is the Addressing Mode
Lw $t0,32(s3)


A. Register addressing
B. Immediate addressing
C. Base addressing
D. PC-relative addressing

Ans:C

13. What is the Addressing Mode
beq $t0,$3,Label


A. Register addressing
B. Immediate addressing
C. Base addressing
D. PC-relative addressing
Ans:D

14. What is the Addressing Mode
J 2000

A. Register addressing
B. Immediate addressing
C. Base addressing
D. PC-relative addressing
E. Pseudo direct Addressing
Ans:E