Difference between revisions of "SP0256 Page Prefix"
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The Page Prefix register provides the upper 4 bits of the address for [[SP0256 JSR|JSR]] instructions, as well as branches initiated by an external [[SP0256 Address Load]] command. | The Page Prefix register provides the upper 4 bits of the address for [[SP0256 JSR|JSR]] instructions, as well as branches initiated by an external [[SP0256 Address Load]] command. | ||
| − | (Unsure: Do JSRs push 12-bit or 16-bit addresses...? I think they push 16-bit, so | + | (Unsure: Do JSRs push 12-bit or 16-bit addresses...? I think they push 16-bit, so [[SP0256 RTS|RTS]] always returns to the right place. Need to check.) |
Revision as of 22:40, 18 January 2005
The Page Prefix register provides the upper 4 bits of the address for JSR instructions, as well as branches initiated by an external SP0256 Address Load command.
(Unsure: Do JSRs push 12-bit or 16-bit addresses...? I think they push 16-bit, so RTS always returns to the right place. Need to check.)
