Carpinelli's RS-CPU : ALU Design

First collate all transfers that modify the Accumulator

LDAC5:  AC           DR

 
MOVR1:  AC           R

 
ADD1 :  AC           AC + R

 
SUB1 :  AC           AC - R

 
INAC1:  AC           AC + 1

 
CLAC1:  AC           0

 
AND1 :  AC           AC    R


 
OR1  :  AC           AC    R


 
XOR1 :  AC           AC    R


 
NOT1 :  AC           AC'

AC           BUS


AC          BUS


AC          AC + BUS


AC          AC - BUS


AC          AC + 1


AC          0




Arithmetic instructions showing operand source