83Plus:OS:ByROMPage
Contents
ROM Page 1B / 3B / 7B
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.
See Also
ROM Page 1F / 3F / 7F
Boot Code page. Hardware-specific. Currently know Boot Code page versions are 1.00 and 1.02.
- This page contains a list of 3-byte vectors for ROM calls, starting at $4018.
- There appears to be a partial Large Font table starting at 1.00:$6D81 / 1.02:$7184 (Boot Code version:address) containing $F1 characters, excluding the null. (Meaning that at that address, you will find the character whose ASCII code is $01 instead of $00). Each table entry (which corresponds with each character sprite) is in the form: width, 7-byte right-aligned sprite.
- A null-terminated string representation of the current Boot Code version is at $400F. E.g. "1.02 "
- The vector at address $4084 points to the following pseudocode routine:
ld hl,0 ld (844B),hl ld hl,pointer->.db "BOOT Code ",0 call PutS ld hl,pointer->.db "1.0X ",0 call PutS ret
- Knowing this, you can find the pointer to the string "BOOT Code ", which is the first entry of the following series of null-terminated strings:
- "BOOT Code ", "FLASH", "RAM", "ID", "OK", " FAILED", "Testing flash", "Waiting...", "Please Install", "operating", "system now."
- You can also find the pointer to the Boot Code's version of PutS.
- 1.00:$5EB3 / 1.02:$5EF7 contains the following series of null-terminated strings:
- "Receiving...", "Operating", "System", "ERROR!", "Press any key to", "turn unit off.", "Then turn unit", "back on.", "Validation Error", "Validating...", "your batteries", "are low.", "Battery", "change is", "required."
- In version 1.02, this series is immediately followed by the null-terminated string "Version Error ".
ROM Page 34 / 74
Contains exclusively USB-related routines.
ROM Page 35 / 75
(highly likely) also contains USB-related routines.
ROM Page 36 / 76
Is the bulk of the DUSB protocol code.
ROM Page 37 / 77
Contains a bunch of app related utility routines (like the ones to parse for the openlib/usb app headers) and had about 6KB of free space in 2.30
