Difference between revisions of "Stack Mode"

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* Reads via R6 decrement R6 prior to using its value.  No other indirect reads have that behavior.
 
* Reads via R6 decrement R6 prior to using its value.  No other indirect reads have that behavior.
* Stack Mode accesses reads take 3 extra cycles.
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* Reading an operand using Stack Mode takes 3 extra cycles.
 
* The [[CP1610]] does not officially support [[SDBD]] with Stack Mode.
 
* The [[CP1610]] does not officially support [[SDBD]] with Stack Mode.
  
 
Stack Mode instructions have the same encoding as [[Indirect Mode]] and [[Immediate Mode]] instructions.
 
Stack Mode instructions have the same encoding as [[Indirect Mode]] and [[Immediate Mode]] instructions.

Revision as of 21:22, 8 January 2006

Stack Mode is simply Indirect Mode via register R6, the stack pointer. GI documentation mentions stack mode separately for three reasons:

  • Reads via R6 decrement R6 prior to using its value. No other indirect reads have that behavior.
  • Reading an operand using Stack Mode takes 3 extra cycles.
  • The CP1610 does not officially support SDBD with Stack Mode.

Stack Mode instructions have the same encoding as Indirect Mode and Immediate Mode instructions.