Do Program Counter Registers need a write-enable control?

WBahn

Joined Mar 31, 2012
26,301
Depends on details you haven't shown. Every architecture has it's own needs. If we try to answer we are making assumptions about a few things because we lack the context.

Besides, YOU need to make YOUR best attempt at answering and explaining that question. That will also help establish the needed context.
 

Papabravo

Joined Feb 24, 2006
14,684
A write enable control would allow the contents to be altered to implement a branch or a call instruction. Since the incrementing is done with an adder how else are you going to advance the Program Counter if you don't have a write enable?
 

WBahn

Joined Mar 31, 2012
26,301
A write enable control would allow the contents to be altered to implement a branch or a call instruction. Since the incrementing is done with an adder how else are you going to advance the Program Counter if you don't have a write enable?
The crux of the question is whether the write enable needs to be controlled, versus just tying it so that it is permanently enabled.
 

ronsimpson

Joined Oct 7, 2019
1,017
Since the incrementing is done with an adder how else are you going to advance the Program Counter if you don't have a write enable?
good point.
When will you not need a write? It seems to me that every instruction you will increment or load new address and never will you do nothing. So if you had a enable/disable pin it would always be in the write position.
 

WBahn

Joined Mar 31, 2012
26,301
good point.
When will you not need a write? It seems to me that every instruction you will increment or load new address and never will you do nothing. So if you had a enable/disable pin it would always be in the write position.
Let's let the TS think about HIS homework problem and offer something up.
 
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