Conditional Call

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SIVAJANAKIRAMAN

Joined Jul 21, 2012
1
Dear All,
I want to know how conditional Call takes 9T-states when condition fails.
Exactly what is that 2nd machine cycle. In Nagoorkani book it is given as Memory read. what does it reads?

thanks in advance.
 

Papabravo

Joined Feb 24, 2006
15,092
The conditional call is a three(3) byte instruction. The 8085 has an 8-bit data bus. Those three bytes must be read by MEMRD (Memory Read) cycles. Now the condition can be evaluated at ANY point during those three MEMRD cycles. If the condition is FALSE execution continues where the PC (Program Counter) is pointing; at the opcode of the next instruction.
 

JohnInTX

Joined Jun 26, 2012
4,377
Just curious for the OP, what are you doing with the 8085? I've written a bunch of 8080/5 code but that was decades ago.. Great part but who is still using it?
 
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