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ECEN 248 Lab 7: Carry Look Ahead and Carry Save Adders. Dept. of Electrical and Computer Engineering. Lab 4 in Brief. Design a 2 operand 16-bit Carry-Look-Ahead Adder Design 3 operand 16-bit Carry-Save Adder How do they Differ?
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ECEN 248Lab 7: Carry Look Ahead and Carry Save Adders Dept. of Electrical and Computer Engineering
Lab 4 in Brief • Design a 2 operand 16-bit Carry-Look-Ahead Adder • Design 3 operand 16-bit Carry-Save Adder • How do they Differ? They differ in the way carry is computed. Carry takes the maximum time to be computed so if we can do it faster then we get faster adders.
Carry Look-Ahead Adder Design Carry-Look Ahead Adder Block Carry Save Adder Block
Carry Look-Ahead Adder Design 4-bit Carry-Look Ahead Adder Ci+1 = Gi + Pi.Ci Gi = Ai.Bi Pi= (AiÅ Bi)
Carry Look-Ahead Adder Design 16-bit Carry-Look Ahead Adder using 4-bit Carry-Look-Ahead Adders PG= P3.P2.P1.P0; GG = G3 + P3G2 + P3.P2.G1. + P3.P2.P1.G0
Carry Save Adder Design Example of Carry Save Addition
Carry Save Adder Design Single Bit Carry Save Adder Block The Full adder Block from Lab#5 can be reused as the carry-save adder unit
Carry Save Adder Design 3 Operand Carry-Save Addition Carry-Look Ahead Adder is used in final stage for the final addition
Specifics and Design Hints • LCD Display for Design 1 • LCD Display for Design 2
Deadlines • Today • Work on Lab 7 • Next Week • Lab 7 Post-Lab due • Lab 8 Pre-Lab due at the beginning of class