Difference between revisions of "83Plus:OS:ByROMPage"
(Got bored and added some information - the table might need work...) |
m (83Plus:OS:ROMPage1B moved to 83Plus:OS:ByROMPage) |
(No difference)
| |
Revision as of 10:10, 9 September 2006
This page contains at the start a list of 3-byte vectors for ROM calls. This is then used by the B_CALL routine to determine what address on what page each ROM call resides. This is page 1B for the TI-83 Plus, 3B for the TI-84 Plus and 7B for the TI-83 Plus Silver Edition & the TI-84 Plus Silver Edition.
Structure
Each 3-byte vector contains an address and a page number. The address comes first, stored in little-endian format, followed by the page number.
| Address | Common Name | LSB Addr. Ptr. | MSB Addr. Ptr. | Page Number |
|---|---|---|---|---|
| 4000 | JErrorNo | C7 | 25 | 00 |
| 4003 | FontHook | A3 | 77 | 7B |
| 4006 | LocalizeHook | 44 | 77 | 7B |
Note: The preceding values were obtained from TI-OS v1.15. Values on other OSs are most likely to differ.
In this manner, TI can change the address pointer and page of the actual routine on a different OS version (e.g. they needed to update a section of code) and the B_CALL routine would still point to the correct page and address.
