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Y Index Register: Difference between revisions
From SnesLab
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The [[Y Index Register]] exists on 65x processors and often holds the current index when iterating over things. | The [[Y Index Register]] exists on 65x processors and often holds the current index when iterating over things. It can be incremented or decremented by one with [[INY]] or [[DEY]], but there is no instruction to add or subtract more than one. | ||
On the [[S-SMP]] it is always 8 bits wide. On the [[65c816]], it may be 8 or 16 bits wide. | On the [[S-SMP]] it is always 8 bits wide. On the [[65c816]], it may be 8 or 16 bits wide. | ||
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=== See Also === | === See Also === | ||
* [[LDY]] | * [[LDY]] | ||
* [[STY]] | * [[STY]] | ||
Revision as of 02:17, 1 August 2024
The Y Index Register exists on 65x processors and often holds the current index when iterating over things. It can be incremented or decremented by one with INY or DEY, but there is no instruction to add or subtract more than one.
On the S-SMP it is always 8 bits wide. On the 65c816, it may be 8 or 16 bits wide.
Unlike the X index register, there are no instructions to transfer value of the stack pointer to/from Y.
See Also
Reference
- 8.1.3 of page 3-8-4 of Book I of the official Super Nintendo development manual