Comparative ROM Atlas: From ZX Spectrum to 2068

To convert SPECTRUM software to the 2068, you need the location and function of ROM routines in each. You can buy the annotated ROM disassembly from Melbourne House or Zebra Systems. Timex sells the 2068 technical manual. Our cross-index links the two ROMs.

This atlas lists routines in order of their hex address in the SPECTRUM ROM and provides the hex address for the corresponding 2068 routine. Labels and names for the SPECTRUM routines come from The Complete Spectrum ROM Disassembly by Ian Logan and Frank O’Hara. All labels and names for 2068 functions come from Corcoran and Branigin‘s Timex 2068 Technical Manual.

To disassemble the TS2068 Home ROM and 8K Extension ROM (EXROM), you will need a program like HOT Z (Reviewed in SYNTAX May 84). HOT Z has a large names file which you can load along with the program to provide subroutine names and some labels for the disassembly. HOT Z self-starts in disassembly mode, to display the Home ROM from 0000h.

In order to disassemble or use EXROM routines, you must enable the bank-switching logic, perform the desired task, then de-activate the EXROM. The 8K EXROM overlays the first 8K chunk of the 16K Home ROM.

To illustrate, the following code copies EXROM to RAM at 8000h, from which you can disassemble or display it.

DI             :    LD BC,2000
LD A,01        :    LDIR
OUT (F4),A     :    XOR A
IN A,(FF)      :    OUT (FF),A
SET 7,A        :    OUT (F4),A
OUT (FF),A     :    EI
LD HL,0000     :    RET
LD DE,8000     :

Headscan (SYNTAX Sep.84) MC is an example of EXROM use. If you want to change the header storage location in RAM, change LD IX,FA3C to, say, LD IX,8000.

Finally, a note concerning the cassette routines of the 2068. All are located in the EXROM, but use subroutines and RST’s in the Home ROM. When a call to the Home ROM or RST occurs, bank switching must take place. This adds code to the SPECTRUM documented by Logan.

Corresponding to every CALL or RST in SPECTRUM cassette routines, you find, in the TS2068 EXROM, a 23-byte code segment which starts with PUSH IX and ends with POP IX. This code preserves and sets up registers and calls the service routine at 0F99h in the EXROM. The service routine transfers the calls to the bank switching code in 2068 RAM, which in turn completes the call to the Home ROM.

SPECTRUM LABEL, NAME	SPECTRUM ROM Addr	TS 2068 ROM Addr	TS 2068 LABEL, NAME
START	0000	0000	PLUGIN
ERROR-1	0008	0008
PRINT-A-1	0010	0010	WRCH
GET-CHAR	0018	0018
NEXT-CHAR	0020	0020
FP-CALC	0028	0028
BC-SPACES	0030	0030
MASK-INT	0038	0030
	004F	004F	PHLAF
ERROR-2	0053	0053
ERROR-3	0055	0055	LE3
RESET	0066	0066
NO-RESET	0070	0070
CH-ADD+1	0074	0074	NEXTCH
TEMP-PTR1	0077	0077	NC-HL
TEMP-PTR2	0078	0078	TC-HL
SKIP-OVER	007D	007D
TOKENS	0095	0098	TOKENS
KEYTBL	0227	0245
KEY-SCAN	028E	02B0	K-SCAN
KEYBOARD	02BF	02E1	UPD-K
K-REPEAT	0310	0336
K-TEST	031E	035C	K-BASE
K-DECODE	0333	0371	CHCODE
BEEPER	03B5	03F3	PARP
BEEP	03F8	0436	BEEP
PRINT-OUT	09F4	0500	SEND-TV
PO-BACK-1	0A23	053A	P-LFT
PO-RIGHT	0A3D	0554	P-RT
PO-ENTER	0A4F	0566	P-NL
PO-COMMA	0A5F	0576
PO-QUEST	0A69	0580
PO-TV-2	0A6D	0584
	0A9B	05B2	SET-AT
PO-ABLE	0AD9	05F0
PO-STORE	0ADC	05F3	STTVCU
PO-FETCH	0B03	061A	LDTVCU
PO-ANY	0B24	063B
PO-ALL	0B7F	06B4
PO-ATTR	0BDB	0710	ATTBYT
PO-MSG	0C0A	073F	PUTMES
PO-SAVE	0C3B	0776	PR-TV2
PO-SEARCH	0C41	077C
PO-SCR	0C55	0790	TVFUL?
REPORT-5	0C86	07C1	ERR5
TEMPS	0D4D	0888	R-ATTS
CLS	0D6B	08A6	K-CLS
CLS-LOWER	0D6E	08A9	CLLHS
CL-ALL	0DAF	08EA	CLS
CL-SET	0DD9	0914	SET-CUR
CL-SC-ALL	0DFE	0939	SCRL
CL-LINE	0E44	097F	CLS-B
CL-ATR	0E88	09C3
CL-ADDR	0E9B	09D6
COPY	0EAC	0A02	K-DUMP
COPY-BUFF	0ECD	0A23	DUMPPR
CLEAR-PRB	0EDF	0A35	CLPR
COPY-LINE	0EF4	0A4A	PRSCAN
EDITOR	0F2C	0A82	EDIT-K
ADD-CHAR	0F81	0AE7	INSA
ED-EDIT	0FA9	0B12
ED-DOWN	0FF3	0B59
ED-LEFT	1007	0B6B
ED-RIGHT	100C	0B73
ED-DELETE	1015	0B7B	DELSYM
ED-ENTER	1024	0B8A
ED-EDGE	1031	0B97
ED-UP	1059	0BBF
ED-SYMBOL	1076	0BDC
ED-ERROR	107F	0BE9
CLEAR-SP	1097	0BFE	DEL-K
KEY-INPUT	10A8	0C0E	IN-K
ED-COPY	111D	0C83	ECHO
REMOVE-FP	11A7	0D0D	DESLUG
NEW	11B7	0D1D	K-NEW
START/NEW	11CB	0D31	INIT
RAM-SET	1219	0D7F	NEW
MAIN-EXEC	12A2	0E28
MAIN-1	12A9	0E2F	LED18
MAIN-4	1303	0ED8	LED4
REPORT-MSG	1391	0F65
MAIN-ADD	155D	1158
CH-INFO	15AF	11AA	CHINIT
INIT-STR	15C6	11C1	SMINIT
WAIT-KEY	15D4	11CF	RDCH
INPUT-AD	15E6	11E1	INCH
OUT-CODE	15EF	11EA	PUTDIG
PRINT-A-2	15F2	11ED	SENDCH
CHAN-OPEN	1601	1230	SELECT
REPORT-O	160E	123D	ERRO
CHAN-FLAG	1615	1248	SEL-HL
CHAN-K	1634	129A
CHAN-s	1642	12A8
CHAN-P	164D	12B3
ONE-SPACE	1652	12B8	INS1
MAKE-ROOM	1655	12BB	INSERT
POINTERS	1664	12CA	REMGSZ
LINE-ZERO	168F	131E
LINE-NO	1695	1324	GET-LN
RESERVE	169E	132D	LCU2
SET-MIN	16B0	133F	CLEL
SET-WORK	16BF	134E	X-CALC
REC-EDIT	16D4	1363	X-T-HL
SET-STK	16C5	1354	RESET
INDEXER	16DC	136B	SEARCH
		1374	SRCHSC
CLOSE	16E5	139F	CLOSE
	16EB	13A8	RSTSTR
CLOSE-2	1701	13BE	CLCHAN
OPEN	1736	142A	OPEN
OPEN-1	1756	145E
OPEN-2	175D	1465	OPCHAN
CAT-ETC.	1793	25C8	CAT
AUTO-LIST	1795	14E1	LIST
LLIST	17F5	1541	K-LLST
LIST	17F9	1545	K-LIST
	1860	15AC	LPO
OUT-LINE	1855	15A1	PUT-SR?
OUT-LINE2	187D	15C9	PUT
NUMBER	18B6	1602
OUT-FLASH	18C1	160D	FLASHA
OUT-CURS	18E1	162D	PR-CUR
LN-FETCH	190F	165B	NEXT-L
LN-STORE	191C	1668	DE-HL
OUT-SP2	1925	1671
LINE-ADDR	196E	16D6	FIND-L
CP-LINES	1980	16E8	CP-BC
	1988	16F0	SUBLIN
EACH-STMT	198B	16F3	SUBLN1
NEXT-ONE	19B8	1720	RECLEN
DIFFER	19DD	1745
RECLAIM-1	19E5	174D	DEL-DE
RECLAIM-2	19E8	1750	DELREC
E-LINE-NO	19BF	1768	LINENO
OUT-NUM-1	1A1B	1788	PUT-BC
OUT-NUM-2	1A28	1795	PU-LN
OUT-NUM-3	1A30	179D
LINE-SCAN	1B17	1A27	SYNTAX
STMT-LOOP	1B28	1A44	LS4
SEPARATOR	1B6F	1AB2
STMT-RET	1B76	1AB9
LINE-RUN	1B8A	1AD8	EXCUTE
LINE-NEW	1AEC	1B9E
REM	1BB2	1B00
LINE-END	1BB3	1B09
LINE-USE	1BBF	1B15
NEXT-LINE	1BD1	1B27
STMT-RET	1B76	1AB9	ENDSTT
CHECK-END	1Bee	1B44	END?
STMT-NEXT	1BF4	1B4A	ENDTEM
CLASS-01	1C1F	1B82	TEM1
REPORT-2	1C2E	1B91	ERR2
VAL-FET-2	1C59	1BBC	LT22
NEXT-2-NUM	1C79	1BDC	DYADIC
CLASS-06	1C82	1BE5	TEM6
REPORT-C	1C8A	1BED	SYNERR
CLASS-0A	1C8C	1BEF	TEM10
PERMS	1C96	1BF9
FETCH-NUM	1CDE	1C49	OPTNO
USE-ZERO	1CE6	1C51	STK-0
STOP	1CEE	1C59	STOP
IF	1CF0	1C5B
FOR	1D03	1C78	FOR
LOOK-PROG	1D86	1D28	SKIP
NEXT	1DAB	1D55	NEXT
READ	1DEC	1D96	READ
DATA	1E27	1E82	DATA
RESTORE	1E42	1E9D
RANDOMIZE	1E4F	1ED4	RAND
REST-RUN	1E45	1ECA	RESTBC
CONTINUE	1E5F	1EE4	CONT
GO TO	1E67	1EF1	JUMP
OUT	1E7A	1F04
POKE	1E80	1F0A
TWO-PARAM	1E85	1F0F
FIND-INT1	1E94	1F1E	FIX-U1
FIND-INT2	1E99	1F23	FIX-U
REPORT-B	1E9F	1F29	ERRB
RUN	1EA1	1F2E
CLEAR	1EAC	1F36	CLEAR
CLEAR-RUN	1EAF	1F39	CLR-BC
GOSUB	1EED	1F99	GO-SUB
TEST-ROOM	1F05	1FBB	CHK-SZ
REPORT-4	1F15	1FCF	ERR4
RETURN	1F23	1FD4	RETURN
PAUSE	1F3A	1FEF	PAUSE
BREAK-KEY	1F54	2009	BREAK
DEF FN	1F60	201D	DEF
****	****	2128	SOUND
UNSTACK-Z	1FC3	214F
LPRINT	1FC9	2155	K-LPR
PRINT	1FCD	2159	K-PRN
PRINT-2	1FDF	217E	P-SEQ
PRINT-CR	1FF5	2194
PRINT-ITEM1	1FFC	219B
PR-STRING	203C	21DB
PR-END-Z	2045	21E4
PR-ST-END	2048	21E7	TERM?
PR-POS-1	204E	21ED
STR-ALTER	2070	220F	STRITO
INPUT	2089	222B	INPUT
IN-ITEM-1	20C1	226B	I-SEQ
IN-ASSIGN	21B9	2363
REPORT-H	21D4	237E	ERRH
IN-CHAN-K	21D6	2380	NOTKB?
CO-TEMP-1	21E1	238B
CO-TEMP-2	21E2	238C	GR-COL
CO-TEMP-4	21FC	23A6	COLITM
CO-TEMP-7	2234	23DE	COLOUR
CO-CHANGE	226C	2416
CO-TEMP-C	2273	241D	HIFLSH
BORDER	2294	243E	BORDER
****	****	24D2	NEWDEV
****	****	25B9	PASSEM
PIXEL-ADD	22AA	2603	SCRMBL
POINT	22CB	2624	F-PNT
PLOT	22DC	2635	PLOT
PLOT-SUB	22E5	263E	PLOTBC
STK-TO-BC	2307	2660	GETXY
STK-TO-A	2314	266D
CIRCLE	2320	2679	CIRCLE
DRAW	2382	26DB	DRAW
CD-PRMS1	247D	27D6
DRAW-LINE	24B7	2810	DRAW-L
SCANNING	24FB	2854	EXPRN
SYNTAX-Z	2530	2889	INTPT?
S-ATTR-s	2580	28D7	F-ATTR
S-U-PLUS	25AF	296D
S-LETTER	26C9	2A87
S-FN-SBRN	27BD	2B7B
S-SCREEN$-S	2535	288E	F-SCRN
S-RND	25F8	29B6	RND
S-PI	2627	29E5	F-PI
S-INKEY$	2634	29F2	F-INKEY
FN-SKPOVER	28AB	2C69	NXT-HL
LOOK-VARS	28B2	2C70	FIND-N
STK-F-ARG	2951	2D0F
STK-VAR	2996	2D54	GET-EL
SLICING	2A52	2E10	SLICER
STK-ST-0	2AB1	2E6F
STK-STO-1	2AB2	2E70	PSHSTR
STK-STORE	2AB6	2E74	PAEDCB
INT-EXP-1	2ACC	2E8A
DE,(DE+1)	2AEE	2EAC
GET-HL*DE	2AF4	2EB2
LET	2AFF	2EBD	LET
L-ENTER	2BA6	2F64
L-ADD-$	2BAF	2F6D
L-STRING	2BC6	2F84
L-FIRST	2BEA	2FA8
STK-FETCH	2BF1	2FAF	POPSTR
DIM	2C02	2FC0	DIM
ALPHANUM	2C88	3046	ALNUM?
ALPHA	2C8D	304B	ALPHA?
DEC-TO-FP	2C9B	3059	STKSUM
NUMERIC	2D1B	30D9	DIGIT?
STK-DIGIT	2D22	30E0
STACK-A	2D28	30E6	STK-A
STACK-BC	2D2B	30E9	STK-BC
INT-TO-FP	2D3B	30F9	ININT
E-TO-FP	2D4F	3100
INT-FETCH	2D7F	313D	LDDE
P-INT-STO	2D8C	314A	STDE-U
INT-STORE	2D8E	314C	STDE-S
FP-TO-BC	2DA2	3160	FP2BC
LOG(2↑A)	2DC1	317F
FP-TO-A	2DD5	3193	FP2A
PRINT-FP	2DE3	31A1	OUTPUT
CA=10*A+C	2F8B	334A
PREP-ADD	2F9B	335A
FETCH-TWO	2FBA	3379	SUMSLD
SHIFT-FP	2Fdd	339C	SHIFT
ADD-BACK	3004	33C3
SUBTRACT	300F	33CE	SUB
addition	3014	33D3	ADD
HL=HL*DE	30A9	3468	MULT
PREP-M/D	30C0	347F
multiply	30CA	3489
REPORT-6	31AD	356C	ERR6
division	31AF	356E	DIVIDE
truncate	3214	35D3	TRUNC
RE-ST-TWO	3293	3052
multiply	30CA	3489	TIMES
RE-STACK	3297	3656	FLOAT
FP calculator start:	32C5	3684
CALCULATE	335B	371A	CTRO
fp-calc-2	33A2	3761
TEST-5-SP	33a9	3768	ROOM?
STACK-NUM	33B4	3773	STK-M
MOVE-FP	33C0	377F	RAMNO
STK-DATA	33C6	3785
SKIP-CONS	33F7	37B6
LOC-MEM	3406	37C5	ARRAY
get-mem-0	340F	37CF
stk-zero	341B	37DA
st-mem-0	342D	37EC
EXCHANGE	343C	37FB
series-06	346A	3829
NEGATE	346E	382D	NEGATE
sgn	3492	3851
in	34A5	3864
peek	34AC	386B
usr-no	34B3	3872
usr-$	34BC	38D7
TEST-ZERO	34E9	3904	TEST0
GREATER-0	34F9	3914
NOT	3501	391C
less-0	3506	3921
FP-0/1	350B	3926	STBOOL
or	351B	3936
no-&-no	3524	393F
str-&-no	352D	3948
no-l-eql	353B	3956
strs-add	359C	39B7
STK-PNTRS	35BF	39DD
chr$	35C9	39E4
val-&-val$	35DE	39F9
str$	361F	3A3A
read-in	3645	3A60
code	3669	3A84
len	3674	3A8F
dec-jr-nz	367A	3A95
JUMP	3686	3AA1
jump-true	368F	3AAA
end-calc	369B	3AB6
n-mod-m	36A0	3ABB	INTDIV
****	****	3AC5	LDMES
int	36AF	3ACA	INT
EXP	36C4	3ADF	EXP
ln	3713	3B2E
get-argt	3783	3B9E	ANGLE
cos	37AA	3BC5	COS
sin	37B5	3BD0	SIN
tan	37DA	3BF5	TAN
atn	37E2	3BFD	ATN
asn	3833	3C4E	ASN
acs	3843	3C5E	ACS
sqr	384A	3C65	ROOT
to-power	3851	3C6C	TO-THE
****	****	3C89	SEPRMT
(note:SEPRMT are tape msgs.)
‘spare’	386E	3CDC	‘EMPTY’
charctr-set	3D00	3D00	CH-SET

The Spectrum does not support the following routines:

SPECTRUM LABEL, NAME	SPECTRUM ROM Addr	TS 2068 ROM Addr	TS 2068 LABEL, NAME
****	****	17B5	AROS
****	****	17CF	GETAL
****	****	17EA	AR-LN
****	****	17FF	AR-NXT
****	****	18C6	AAROS

TIMEX EXROM

SPECTRUM LABEL, NAME	SPECTRUM ROM Addr	TS 2068 ROM Addr	TS 2068 LABEL, NAME
SA-BYTES	04C2	0068	W-TAPE
SA-LEADER	04D8	007E
SA-LOOP	04FE	00A4
SA-BIT-2	0511	00B7
SA-8-BITS	0525	00CB
SA/LD-RET	053F	00E5	W-BORD
REPORT-D	0552	00F8
LD-BYTES	0556	00FC	R-TAPE
LD-BREAK	056B	0111
LD-LEADER	0580	0126
LD-SYNC	058F	0135
LD-8-BITS	05CA	0170
LD-EDGE-2	05E3	0189	RD-BIT
LD-EDGE-1	05E7	018D	RD-EDGE
LD-SAMPLE	05ED	0193
SAVE-ETC	0605	01AB	SLVM
REPORT-F	0642	0228
SA-NAME	064B	0231
SA-DATA	0652	0238
SA-V-OLD	0672	029A
SA-V-NEW	0685	02A9
SA-SCR$	06A0	02F2
SA-CODE	06C3	032E
SA-LINE	0716	0447
SA-ALL	075A	04C9
LD-LOOK-H	0767	04D6
LD-NAME	07A6	053D
VR-CONTROL	07CB	058F	VERIFY
LD-BLOCK	0802	05C6
LD-CONTROL	0808	05CC	LOAD
LD-DATA	082E	0606
LD-PROG	0873	0673
ME-CONTROL	08B6	06E5	MERGE
ME-OLD-VP	08F9	0752
ME-ENTER	092C	0799
ME-ENT-1	093E	07CF
ME-ENT-3	0958	0825
SA-CONTROL	0970	0851	SAVE
SA-1-SEC	0991	089A

The balance of EXROM contains the Function Dispatcher , Bank Switching Code , and various other routines , which does not have counterparts in the Spectrum. A total of approximately 2K Bytes of EXROM is unused.