Difference between revisions of "SP0256 Program Counter"

From Intellivision Wiki
Jump to: navigation, search
Line 1: Line 1:
 +
[[Category:Intellivoice]]
 +
 
The microsequencer in the SP0256 conceptually maintains a 19-bit Program Counter.  The upper 16 bits of the PC form a byte address.  On control transfers (branches and returns), the upper 16 bits of the PC get set to the byte address of the target, and the lower 3 bits initialize to 0.
 
The microsequencer in the SP0256 conceptually maintains a 19-bit Program Counter.  The upper 16 bits of the PC form a byte address.  On control transfers (branches and returns), the upper 16 bits of the PC get set to the byte address of the target, and the lower 3 bits initialize to 0.
  
 
All serial speech ROMs keep a shadow copy of the PC as a function of the [[SP0256 Serial Bus Protocol]].
 
All serial speech ROMs keep a shadow copy of the PC as a function of the [[SP0256 Serial Bus Protocol]].

Revision as of 22:43, 18 January 2005


The microsequencer in the SP0256 conceptually maintains a 19-bit Program Counter. The upper 16 bits of the PC form a byte address. On control transfers (branches and returns), the upper 16 bits of the PC get set to the byte address of the target, and the lower 3 bits initialize to 0.

All serial speech ROMs keep a shadow copy of the PC as a function of the SP0256 Serial Bus Protocol.