Some more routines were finally added in, especially the string -> float extended-precision routine. I still need to implement some if the trig routines, but I only have 565 bytes of space left :| I might need to look into ways to reduce the size of the built-in documentation. Here is the compiled app, the source is up on GitHub.

1) What RAM pages can I use within programs without having any bad consequences?

Even numbered pages are execution protected by default, so executing code here will crash your calc. That said, you can definitely store data. On the calcs with USBs, page 83h has some data that should be preserved or restored in the first 128 bytes. Just remember that any OS routines that interact with memory or variables expect the right pages to be there.

Ram Pages (WikiTI)

2) When an appvar is less than 16kb and is archived, will it all be on the same ROM page?

No, you can't expect this. Variables won't cross sector boundaries (groups of four RAM pages), but they may cross pages.

3) Can you interface with headphones beyond simply sending them signals with the ring and the tip? If so, how?

I don't know what you mean by this, sorry :| If you want to use headphones, you have to interact directly with port 0.

Thanks for posting the answer for future reference!

Requires Grammer 2.50.1.1 and up.

This program gives you the zeros of a quadratic function! Inputs must include a decimal point so that Grammer knows it is a float. Hopefully that can be fixed in the future. Also it looks like Grammer has some float issues, so it gives weird answers when the result is complex.

Here is my take on it (not the whole code):
  ld c,(hl);grab string size
  inc hl
  ld b,(hl)
  inc hl
loop:
  ld a,(hl)   ;Need to check if it is a two-byte token, later
  push af   ;Save A for later
  push hl
  push bc
  bcall(_Get_Tok_Strng)
  ld hl,op3-1    ;point to the byte *before* the output characters.
tokenloop:
  push hl     ;save HL
  push bc    ;and BC
  call CheckXPos
  pop bc
  pop hl
  inc hl   ;Need to increment first to get to the character since we started one byte behind
  ld a,(hl)
  bcall(_VPutMap)
  dec c
  jr nz,tokenloop
  pop bc
  pop hl
  pop af
  bcall(_IsA2ByteTok) ;Check if it was a 2 byte token
  jr nz,+_
  inc hl  ;increment hl for next calc since token was 2 bytes
  dec bc  ;decrement bc since token was 2 bytes
_:
  cpi
  jp pe,loop  ; pe is used to test if BC reached 0.
  bcall(_getKey)
  ret
CheckXPos:
  ld (hl),1  ;Just want a 1-byte string. HL points to an already drawn char, so no need to save it
  bcall(_SStringLength) ;Returns length in A and B
  ld a,(penCol)
  add a,b ; Grab the future penCol position
  ld b,a
  dec b
  dec b
  ld a,(mX)
  cp b ; call Resetcur if pencol > mX
  ret nc
Resetcur:
  ld a,(cX)
  inc a ;if pencol > mX, change the cursor position
  inc a ;to next line before writing
  ld (penCol),a
  ld a,(penRow)
  add a,6
  ld (penRow),a
  ret


You can use the _Get_Tok_Str bcall to convert a token to it's characters. Another routine that might be useful to you later is _SStringLength which calculates how many pixels wide a string is in the variable-width (small) font.

Necroposting is generally frowned upon (the last post was over 5 years ago); ideally you should create a new topic. That said, cool!
I don't see how it sorts or anything :| To me it looks like it just filters out programs