Greetings,
This past weekend I was examining the CEdev Toolchain <ti\screen.h> fiile.
I came across these six defined memory locations:
os_PromptRow, os_PromptCol, os_PromptIns
os_PromptShift, os_PromptRet, os_PromptValid
There are no comments explaining what they are for in either screen.h or in ti84pceg.inc.
Since they were specifically defined in screen.h, I assume they are used for something often enough that it was necessary to define them. Any information would be appreciated. Thanks

These defines were added a very long time ago, in this commit from 2016 which added a lot of other defines. I feel like it's more likely that they were added because they were some of the only memory locations known at the time, rather than for their potential utility.

It appears that the first four memory locations are used to back up the current cursor state when entering a variable name for Rcl. PromptRet holds a return address to return to once the prompt is finished. I'm not sure what PromptValid is - it looks like a pointer to something, though I don't know what.

In any case, they don't seem to be very useful for toolchain programs.

Thanks for the info. This is very helpful.