SLIDE 1
CSCI341
Lecture 11, Logical Operations
Image courtesy of http://debsbookbag.blogspot.com/
CSCI341 Lecture 11, Logical Operations Image courtesy of - - PowerPoint PPT Presentation
CSCI341 Lecture 11, Logical Operations Image courtesy of - - PowerPoint PPT Presentation
CSCI341 Lecture 11, Logical Operations Image courtesy of http://debsbookbag.blogspot.com/ vs PERFORMANCE CPU Time = (Instruction Count x CPI) / Clock Rate Clock Rate CPI class A CPI class B CPI class C CPI class D Watermelon 1.5 GHz 1
SLIDE 2
SLIDE 3
PERFORMANCE
vs CPU Time = (Instruction Count x CPI) / Clock Rate
Clock Rate CPI class A CPI class B CPI class C CPI class D Watermelon 1.5 GHz 1 2 3 4 Sour Apple 2 GHz 2 2 2 2
Given a program with 100 instructions, with 10% as class A, 20% class B, 50% class C and 20% class D, which implementation is faster?
SLIDE 4
WHERE WE’VE BEEN
- Understanding & Calculating Computer Performance
- The Power Wall
- Amdahl’s Law
- Fallacies / Pitfalls
- Heat, Costs and the Rise of Parallelism
SLIDE 5
WHERE WE’VE BEEN
- Binary numbers
- Two’s complement (signed) binary numbers
- Addition & Subtraction of signed/unsigned binary numbers
- Binary to decimal to hex representations
- Shortcuts & tricks (negation, sign extension)
SLIDE 6
WHERE WE’VE BEEN
- Fundamental MIPS operations
- Operands and registers $zero, $t*, $s*
- add, sub, addi, lw, sw
- Base addresses and offsets (x4)
SLIDE 7
INSTRUCTIONS (REVIEW)
R-type I-type
(no, not this)
Register operations eg, add, sub Immediate operations eg, addi, and data transfer
SLIDE 8
INSTRUCTION FORMATS
- p
rs rt rd shamt funct 18 8 8 32 $s2 $t0 $t0 add
R
- p
rs rt constant / address 35 9 8 1200 lw $t1 $t0 1200
I
lw $t0, 1200($t1) add $t0, $s2, $t0
SLIDE 9
R-TYPE VS. I-TYPE
SLIDE 10
LOGICAL OPERATIONS
SLIDE 11
LOGICAL SHIFTING
0000 1001 1001 0000 << 1011 0000 0000 1011 >>
SLIDE 12
LOGICAL SHIFTING
0000 1001 1001 0000
sll $t2, $s0, 4
1011 0000 0000 1011
srl $t2, $s0, 4
$s0 $s0 $s0 $s0 $t2 $t2
SLIDE 13
sll, srl Instructions
- p
rs rt rd shamt funct 16 10 4
sll $t2, $s0, 4 What is shamt for srl?
SLIDE 14
WHY GIVE A SHIFT?
- ptimized version of multiplying or dividing by
powers of two! (among other things)
SLIDE 15
and $t0, $t1, $t2 perform bitwise AND operation on values in $t1 and $t2
AND and OR
- r $t0, $t1, $t2
perform bitwise OR operation on values in $t1 and $t2
SLIDE 16
32-bit words.... But what if I want just part of that word?
MASKING
SLIDE 17
MASKING
Given a byte 1011 0100 How might you ‘extract’ or ‘isolate’ the second nibble?
SLIDE 18
MASKING WITH AND
1011 0100 0000 1111 AND 0000 0100 “bit masking”
SLIDE 19
HOMEWORK
- Reading 9: section 2.6
- Problem Set 6 (Instruction formats)
- Project 2 (a simple program)