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CPD

Compare with decrement.
Function: A - [HL]; HL <- HL - 1; BC <- BC - 1
 
Format:
1110 1101
 
byte 1: ED
 
1010 1001
 
byte 2: A9
 
Description: The contents of the memory location addressed by the HL register pair are subtracted from the contents of the accumulator and the result is discarded. Then both the HL register pair and the BC register pair are decremented.
 
Data Flow:
 
Timing:
 
Addressing Mode:
 
Flags:
 
Example:

OBJECT CODE
Before:
 
After: