Difference between revisions of "83Plus:OS:ByROMPage"
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(Got bored and added some information - the table might need work...) |
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[[Category:83Plus:OS Information|ROM Page 1B]] | [[Category:83Plus:OS Information|ROM Page 1B]] | ||
| − | |||
| − | This page contains at the start a list of 3-byte vectors for ROM calls. | + | 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== | ==Structure== | ||
| − | ''to | + | 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. |
| + | {| border="1" cellspacing="0" cellpadding="2" | ||
| + | |+Example Vector Table | ||
| + | |- | ||
| + | ! Address !! Common Name !! LSB Addr. Ptr. !! MSB Addr. Ptr. !! Page Number | ||
| + | |- | ||
| + | ! 4000 | ||
| + | | [[83Plus:BCALLs:4000|JErrorNo]] || C7 || 25 || 00 | ||
| + | |- | ||
| + | ! 4003 | ||
| + | | [[83Plus:BCALLs:4003|FontHook]] || A3 || 77 || 7B | ||
| + | |- | ||
| + | ! 4006 | ||
| + | | [[83Plus:BCALLs: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. | ||
| + | |||
| + | ==See Also== | ||
| + | * [[83Plus:OS:How BCALLs work|How BCALLs work]] | ||
Revision as of 10:39, 13 September 2005
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.
