lec12Datapath - Introduction to CMOS VLSI Design Datapath...

Info iconThis preview shows pages 1–21. Sign up to view the full content.

View Full Document Right Arrow Icon
Introduction to CMOS VLSI Design Datapath Functional Units
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 2 CMOS VLSI Design Outline Comparators Shifters Multi-input Adders Multipliers
Background image of page 2
Datapath Slide 3 CMOS VLSI Design Comparators 0’s detector: A = 00…000 1’s detector: A = 11…111 Equality comparator: A = B Magnitude comparator: A < B
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 4 CMOS VLSI Design 1’s detector: N-input AND gate 0’s detector: NOTs + 1’s detector (N-input NOR) A 0 A 1 A 2 A 3 A 4 A 5 A 6 A 7 allones A 0 A 1 A 2 A 3 allzeros allones A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 0
Background image of page 4
Datapath Slide 5 CMOS VLSI Design Equality Comparator Check if each bit is equal (XNOR, aka equality gate) 1’s detect on bitwise equality A[0] B[0] A = B A[1] B[1] A[2] B[2] A[3] B[3]
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 6 CMOS VLSI Design Magnitude Comparator Compute B-A and look at sign B-A = B + ~A + 1 For unsigned numbers, carry out is sign bit A 0 B 0 A 1 B 1 A 2 B 2 A 3 B 3 A = B Z C A B N A B
Background image of page 6
Datapath Slide 7 CMOS VLSI Design Signed vs. Unsigned For signed numbers, comparison is harder C: carry out Z: zero (all bits of A-B are 0) N: negative (MSB of result) V: overflow (inputs had different signs, output sign B)
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 8 CMOS VLSI Design Shifters Logical Shift: Shifts number left or right and fills with 0’s 1011 LSR 1 = ____ 1011 LSL1 = ____ Arithmetic Shift: Shifts number left or right. Rt shift sign extends 1011 ASR1 = ____ 1011 ASL1 = ____ Rotate: Shifts number left or right and fills with lost bits 1011 ROR1 = ____ 1011 ROL1 = ____
Background image of page 8
Datapath Slide 9 CMOS VLSI Design Shifters Logical Shift: Shifts number left or right and fills with 0’s 1011 LSR 1 = 0101 1011 LSL1 = 0110 Arithmetic Shift: Shifts number left or right. Rt shift sign extends 1011 ASR1 = 1101 1011 ASL1 = 0110 Rotate: Shifts number left or right and fills with lost bits 1011 ROR1 = 1101 1011 ROL1 = 0111
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 10 CMOS VLSI Design Funnel Shifter A funnel shifter can do all six types of shifts Selects N-bit field Y from 2N-bit input Shift by k bits (0 k < N) B C offset offset + N-1 0 N-1 2N-1 Y
Background image of page 10
Datapath Slide 11 CMOS VLSI Design Funnel Shifter Operation Computing N-k requires an adder
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 12 CMOS VLSI Design Funnel Shifter Operation Computing N-k requires an adder
Background image of page 12
Datapath Slide 13 CMOS VLSI Design Funnel Shifter Operation Computing N-k requires an adder
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 14 CMOS VLSI Design Funnel Shifter Operation Computing N-k requires an adder
Background image of page 14
Datapath Slide 15 CMOS VLSI Design Funnel Shifter Operation Computing N-k requires an adder
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 16 CMOS VLSI Design Simplified Funnel Shifter Optimize down to 2N-1 bit input
Background image of page 16
Datapath Slide 17 CMOS VLSI Design Simplified Funnel Shifter Optimize down to 2N-1 bit input
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 18 CMOS VLSI Design Simplified Funnel Shifter Optimize down to 2N-1 bit input
Background image of page 18
Datapath Slide 19 CMOS VLSI Design Simplified Funnel Shifter Optimize down to 2N-1 bit input
Background image of page 19

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Datapath Slide 20 CMOS VLSI Design Simplified Funnel Shifter Optimize down to 2N-1 bit input
Background image of page 20
Image of page 21
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 54

lec12Datapath - Introduction to CMOS VLSI Design Datapath...

This preview shows document pages 1 - 21. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online