Here is yet another list of miscellaneous information about various ROM and RAM locations in the Mod-100, done as sort of a "Model-100 ROMs commented".  This list will be updated on an ongoing basis as I pick through the Mod-100 ROMs.

     In keeping with the spirit of the disassemblers available, restart (RST) instructions are shown with the hex address they branch to.

     24 August 1983, Robert Briggs, Holmes Engineering [70515,1262]

0000 (0000)     jp     7d33  jump to power on routine
0003 (0003)     defm   'MENU',00h
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11a2 (?????)	display string (HL)=> until 0 byte
	ld	a,(hl)
	or	a
	ret	z
	rst	20h
	inc	hl
	jp	11a2
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1978 (?????)	Day table
	defm	'Sun'
	defm	'Mon'
	defm	'Tue'
	defm	'Wed'
	defm	'Thu'
	defm	'Fri'
	defm	'Sat'
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253d (?????)
	ld	de,(0faceh)  (0faceh)=> ???
2540 (?????)	(HL+)=> to (DE+)=> for 6 bytes
	ld	b,06
2542	ld	a,(hl)
	ld	(de),a
	inc	hl
	inc	de
	dec	b
	jp	nz,2542h
	ret
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25d5 (?????)	more table stuff
	defm	'Top: ',00h
	defm	'End: ',00h
	defm	'Exe: ',00h
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	load *** display control subroutines***

4222 (16930)	send carriage return / line feed to display
	ld	a,0dh
	rst	20h
4225 (16933)    send line feed to display
	ld	a,0ah
	rst	20h
	ret
4229 (16937)    "ring bell"
	ld	a,07h
	rst	20h
422d (16941)	home cursor
	ld	a,0bh
	rst	20h
4231 (16945)	clear screen
	ld	a,0ch
	rst	20h
4235 (16949)	protect label line
	ld	a,'T'
	jp	4270h
423a (16954)    unprotect label line
	ld	a,'U'
	jp	4270h
423f (16959)    lock screen (no scroll)
	ld	a,'V'
	jp	4270h
4244 (16964)    unlock screen (enable scroll)
	ld	a,'W'
	jp	4270h
4249 (16969)    cursor on
	ld	a,'P'
	jp	4270h
424e (16974)    cursor off
	ld	a,'Q'
	jp	4270h
4253 (16979)    delete current line
	ld	a,'M'
	jp	4270h
4258 (16984)    insert line
	ld	a,'L'
	jp	4270h
425d (16989)    erase to end of line
	ld	a,'K'
	jp	4270h
4262 (16994)	clear keyboard buffer
	ld	a,'X'
	jp	4270h
4267 (16999)    A or (HL)=>,  return if Z else RVIDEO ON.
	or	(hl)
	ret	z
4269 (17001)    Rvideo ON
	ld	a,'q'
  	jp	4270h
426E (17006)	RVIDEO OFF
	ld	a,'p'
4270 (17008)    Display ESCAPE character followed by contents of A
	push	af
	ld	a,01bh
	rst	20h
	pop	af
	rst	20h
	ret
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50f1 (?????)	device table
	defm	'LCD',0ffh
	defm	'CRT',0feh
	defm	'CAS',0fdh
	defm	'COM',0fch
	defm	'WAND',0fbh
	defm	'LPT',0fah
	defm	'MDM',0f9h
	defm	'RAM',0f8h
	defb	00h
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517c	(?????) TELCOM text and table

	defm	'Telcom: ',00h

	       text        address
	       ----        -------.
5185	defm	'STAT',	   51c0
518b	defm	'TERM',	   5455
5191	defm	'CALL',	   522f
5197	defm	'FIND',	   534d
519d	defm	'MENU',	   5797
51a3	defb	0ffh

Telcom label line

51a4	defm	'Find',0a0h
51a9	defm	'Call',0a0h
51ae	defm	'Stat',0a0h
51b3	defm	'Term',08dh
51b8	defb	80h
51b9	defb	80h	; blank entries
51ba	defb	80h
51bb	defm	'Menu',08dh
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6bdb (?????)	Z-80 LDIR equivalent. (HL+)=> to (DE+)=> for (BC-) bytes
	ld	a,(hl)
	ld	(de),a
	inc	hl
	inc	de
	dec	bc
	ld	a,b
	or	c
	jr	nz,6bdbh
	ret
6be6 (?????)	Z-80 LDDR equivalent (HL-)=> to (DE-)=> for (BC-) bytes
	ld	a,(hl)
	ld	(de),a
	dec	hl
	dec	de
	dec	bc
	ld	a,b
	or	c
	jr	nz,6be6h
6c48	ret

   ROM program entry point table.

         type  location   text
         ----  --------   ----
6c49 defm b0h, 6c49h,	'BASIC  ',00h
6bfc defm b0h, 5deeh,	'TEXT   ',00h
6c07 defm b0h, 5146h,	'TELCOM ',00h
6c12 defm b0h, 5b68h,	'ADDRSS ',00h
6c1d defm b0h, 5b6fh,	'SCHEDL ',00h
6c28 defm 88h, 000000,	'Suzuki '
6c33 defm c8h, 000000,	'Hayashi'
6c3e defm 48h  000000,	'Ricky  '
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Display control codes
         

07h		bell
0ah		line feed
0bh		home cursor
0ch		clear screen
0dh		carriage return

ESC then	result
--------	------
  K		erase to end of line
  L		insert line
  M		delete line
  P		cursor on
  Q		cursor off
  T		protect line 8 (label)
  U		unprotect line 8
  V		lock screen
  W		unlock screen (enable scroll)
  X		clear keyboard buffer
  p		RVIDEO ON
  q		RVIDEO OFF

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Misc RAM locations

F63D (-2499)	# of bottom lines to scroll protect in twos complement
		form. 0=0, 0ffh (255)=1, 0feh (254)=2, etc.
		WARNING: using values from 1 to 247 decimal can lock the
		system up so badly that MEMORY has to be powered off and
		then back on to reset your machine.