We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS

Uppermost Page

From SnesLab
Revision as of 11:16, 20 September 2024 by Xetheria (talk | contribs) (underlying RAM)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

The Uppermost Page is the contiguous region of 256 bytes in ARAM with the highest possible address, located at $FF00. It/offsets within it are abbreviated "upage."[1]

uppermost page.png

Both TCALL and PCALL utilize it.

The 64-byte SPC700/IPL ROM lives in the uppermost page at FFC0h.[2] But, reading this 64-byte region only returns ROM data when bit 7 of the CONTROL register (00F1h) is set. If bit 7 is clear, then the IPL ROM is currently unmapped, revealing 64 bytes of normal ARAM underneath which will be mapped and read instead. Writes to this 64 byte region always affect the underlying RAM even if CONTROL's bit 7 is set.

See Also

References

  1. Appendix C-1 of Book I of the official Super Nintendo development manual
  2. fullsnes
Retrieved from "https://sneslab.net/mw/index.php?title=Uppermost_Page&oldid=20623"