C64 ROM

Memory map

Address	Description
A000	start of the BASIC ROM
A00C	action addresses for primary commands
A052	action addresses for functions
A080	precedence byte and action addresses for operators
A09E	BASIC keywords
A19E	BASIC error messages
A328	error message pointer table
A364	BASIC messages
A389	spare byte, not referenced
A38A	search the stack for FOR or GOSUB activity
A3B8	open up a space in the memory, set the end of arrays
A3FB	check room on stack for A bytes
A408	check available memory, do out of memory error if no room
A435	do out of memory error then warm start
A43A	do error #X then warm start
A469	print string and do warm start, break entry
A474	do warm start
A483	BASIC warm start
A49C	handle new BASIC line
A533	rebuild BASIC line chaining
A560	call for BASIC input
A579	crunch BASIC tokens vector
A57C	crunch BASIC tokens
A613	search BASIC for temporary integer line number
A617	search Basic for temp integer line number from AX
A642	perform NEW
A659	reset execute pointer and do CLR
A65E	perform CLR
A677	do RESTORE and clear stack
A67A	flush BASIC stack and clear the continue pointer
A68E	set BASIC execute pointer to start of memory - 1
A69C	perform LIST
A71A	uncrunch BASIC tokens
A742	perform FOR
A7AE	interpreter inner loop
A81D	perform RESTORE
A82C	do CRTL-C check vector
A82F	perform STOP
A831	perform END
A857	perform CONT
A871	perform RUN
A883	perform GOSUB
A8A0	perform GOTO
A8BC	search for line number in temporary integer from start of memory pointer
A8C0	search for line # in temporary integer from (AX)
A8D2	perform RETURN
A8E8	do syntax error then warm start
A8EB	perform RETURN (continued)
A8F8	perform DATA
A8FB	add Y to the BASIC execute pointer
A906	scan for next BASIC statement ([:] or [EOL])
A909	scan for next BASIC line
A928	perform IF
A93B	perform REM
A94B	perform ON
A96B	get fixed-point number into temporary integer
A9A5	perform LET
AA1D	check and evaluate numeric digit
AA2C	assign value to numeric variable, but not TI$
AA80	perform PRINT#
AA86	perform CMD
AA9A	print string and scan memory
AAA0	perform PRINT
AACA	set XY to $0200 - 1 and print [CR]
AAD7	print CR/LF
AAE8	skip to the next TAB position
AB1E	print null terminated string
AB21	print string from utility pointer
AB3B	print [SPACE] or [CURSOR RIGHT]
AB45	print "?"
AB47	print character
AB4D	bad input routine
AB7B	perform GET
ABA5	perform INPUT#
ABB5	close input and output channels
ABBF	perform INPUT
ABF9	print "? " and get BASIC input
AC06	perform READ
AC0F	perform GET
ACFC	input error messages
AD1E	perform NEXT
AD8A	evaluate expression and check type mismatch
AD9E	evaluate expression
AE20	get vector, execute function then continue evaluation
AE30	do syntax error then warm start
AE33	get vector, execute function then continue evaluation (continued)
AE38	push sign, round FAC1 and put on stack
AE43	round FAC1 and put on stack
AE58	do functions
AE83	get value from line
AE86	get arithmetic element
AF14	check address range
AF28	variable name set-up
AFA7	get value from line continued
AFE6	perform OR
AFE9	perform AND
B016	perform comparisons
B07E	perform DIM
B08B	search for variable
B194	set-up array pointer to first element in array
B1A5	-32768 as floating value
B1AA	convert float to fixed
B1B2	evaluate integer expression
B1D1	find or make array
B37D	perform FRE()
B391	convert fixed integer AY to float FAC1
B39E	perform POS()
B3B3	perform DEF
B3E1	check FNx syntax
B3F4	Evaluate FNx
B449	restore BASIC execute pointer and function variable from stack
B465	perform STR$()
B475	do string vector
B47D	make string space A bytes long
B487	scan, set up string
B4F4	make space in string memory for string A long
B526	garbage collection routine
B63D	concatenate
B67A	copy string from descriptor to utility pointer
B6A3	evaluate string
B6DB	clean descriptor stack
B6EC	perform CHR$()
B700	perform LEFT$()
B72C	perform RIGHT$()
B737	perform MID$()
B761	pull string data and byte parameter from stack
B77C	perform LEN()
B782	evaluate string, get length in Y
B78B	perform ASC()
B798	do illegal quantity error then warm start
B79B	scan and get byte parameter
B79E	get byte parameter
B7A1	evaluate byte expression, result in X
B7AD	perform VAL()
B7E2	restore BASIC execute pointer from temp
B7EB	get parameters for POKE/WAIT
B7F7	convert FAC_1 to integer in temporary integer
B80D	perform PEEK()
B824	perform POKE
B82D	perform WAIT
B849	add 0.5 to FAC1 (round FAC1)
B850	perform subtraction, FAC1 from (AY)
B853	perform subtraction, FAC1 from FAC2
B862	shift FACX A times right
B86A	add FAC2 to FAC1
B8D2	do ABS and normalise FAC1
B8D7	normalise FAC1
B8F7	clear FAC1 exponent and sign
B8FB	save FAC1 sign
B8FE	add FAC2 mantissa to FAC1 mantissa
B947	negate FAC1
B97E	do overflow error then warm start
B983	shift FCAtemp << A+8 times
B9BC	constants and series for LOG(n)
B9EA	perform LOG()
BA28	do convert AY, FCA1*(AY)
BA8C	unpack memory (AY) into FAC2
BAB7	test and adjust accumulators
BAD4	handle overflow and underflow
BAE2	multiply FAC1 by 10
BAF9	10 as a floating value
BAFE	divide FAC1 by 10
BB07	divide by (AY) (X=sign)
BB0F	convert AY and do (AY)/FAC1
BBA2	unpack memory (AY) into FAC1
BBC7	pack FAC1 into $5C
BBCA	pack FAC1 into $57
BBD0	pack FAC1 into variable pointer
BBD4	pack FAC1 into (XY)
BBFC	copy FAC2 to FAC1
BC0C	round and copy FAC1 to FAC2
BC1B	round FAC1
BC2B	get FAC1 sign
BC39	perform SGN()
BC3C	save A as integer byte
BC58	perform ABS()
BC5B	compare FAC1 with (AY)
BC9B	convert FAC1 floating to fixed
BCBB	shift FAC1 A times right
BCCC	perform INT()
BCE9	clear FAC1
BCF3	get FAC1 from string
BD67	do - FAC1
BD6A	do unsigned FAC1*10+number
BD7E	evaluate new ASCII digit
BD91	evaluate next character of exponential part of number
BDB3	limits for scientific mode
BDC2	do " IN " line number message
BDCD	print XA as unsigned integer
BDDD	convert FAC1 to ASCII string result in (AY)
BF11	constants
BF3A	jiffy counts
BF52	not referenced
BF53	spare bytes, not referenced
BF71	perform SQR()
BF7B	perform power function
BFBF	exp(n) constant and series
BFED	perform EXP()
E000	start of the kernal ROM
E043	^2 then series evaluation
E059	do series evaluation
E08D	RND values
E097	perform RND()
E0F6	pack FAC1 into (XY)
E0F9	handle BASIC I/O error
E10C	output character to channel with error check
E112	input character from channel with error check
E118	open channel for output with error check
E11E	open channel for input with error check
E124	get character from input device with error check
E12A	perform SYS
E156	perform SAVE
E165	perform VERIFY
E168	perform LOAD
E195	do READY return to BASIC
E1BE	perform OPEN
E1C7	perform CLOSE
E1D4	get parameters for LOAD/SAVE
E200	scan and get byte, else do syntax error then warm start
E206	exit function if [EOT] or ":"
E20E	scan for ",valid byte", else do syntax error then warm start
E211	scan for valid byte, not [EOL] or ":", else do syntax error then warm start
E219	get parameters for OPEN/CLOSE
E257	set filename
E264	perform COS()
E26B	perform SIN()
E2B4	perform TAN()
E2DC	save comparison flag and do series evaluation
E2E0	constants and series for SIN/COS(n)
E30E	perform ATN()
E33E	series for ATN(n)
E37B	BASIC warm start entry point
E394	BASIC cold start entry point
E3A2	character get subroutine for zero page
E3BA	spare bytes, not referenced
E3BF	initialise BASIC RAM locations
E422	print the start up message and initialise the memory pointers
E447	BASIC vectors
E453	initialise the BASIC vectors
E45F	unused
E460	BASIC startup messages
E4AC	unused
E4AD	open channel for output
E4B7	unused bytes
E4D3	flag the RS232 start bit and set the parity
E4DA	save the current colour to the colour RAM
E4E0	wait ~8.5 seconds for any key from the STOP key column
E4EC	baud rate tables for PAL C64
E500	return the base address of the I/O devices
E505	return the x,y organization of the screen
E50A	read/set the x,y cursor position
E518	initialise the screen and keyboard
E544	clear the screen
E566	home the cursor
E56C	set screen pointers for cursor row, column
E591	find and set the pointers for the start of logical line
E599	orphan bytes ??
E5A0	initialise the vic chip
E5B4	input from the keyboard buffer
E5CA	write character and wait for key
E5CD	wait for a key from the keyboard
E632	input from screen or keyboard
E684	if open quote toggle cursor quote flag
E691	insert uppercase/graphic character
E6B6	advance the cursor
E701	back onto the previous line if possible
E716	output a character to the screen
E87C	do newline
E891	output [CR]
E8A1	test for line decrement
E8B3	test for line increment
E8CB	set the colour code
E8DA	ASCII colour code table
E8EA	scroll the screen
E965	open up a space on the screen
E9C8	shift screen line up/down
E9E0	calculate pointers to screen lines colour RAM
E9F0	fetch a screen address
E9FF	clear screen line X
EA12	orphan byte
EA13	print character A and colour X
EA1C	save the character and colour to the screen @ the cursor
EA24	calculate the pointer to colour RAM
EA31	IRQ vector
EA87	scan the keyboard
EB48	evaluate the SHIFT/CTRL/C= keys
EB79	table addresses
EB81	standard keyboard table
EBC2	shifted keyboard table
EC03	CBM key keyboard table
EC44	check for special character codes
EC78	control keyboard table
ECB9	vic ii chip initialisation values
ECE7	keyboard buffer for auto load/run
ECF0	low bytes of screen line addresses
ED09	command serial bus device to TALK
ED0C	command devices on the serial bus to LISTEN
ED11	send a control character
ED21	defer a command
ED40	Tx byte on serial bus
EDB9	send secondary address after LISTEN
EDBE	set serial ATN high
EDC7	send secondary address after TALK
EDCC	wait for the serial bus end after send
EDDD	output a byte to the serial bus
EDEF	command serial bus to UNTALK
EDFE	command serial bus to UNLISTEN
EE13	input a byte from the serial bus
EE85	set the serial clock out high
EE8E	set the serial clock out low
EE97	set the serial data out high
EEA0	set the serial data out low
EEA9	get the serial data status in Cb
EEB3	1ms delay
EEBB	RS232 Tx NMI routine
EED7	do RS232 parity bit
EF06	setup next RS232 Tx byte
EF2E	set DSR signal not present
EF31	set CTS signal not present
EF39	disable timer A interrupt
EF3B	set VIA 2 ICR from A
EF4A	compute bit count
EF59	RS232 Rx NMI
EF7E	setup to receive an RS232 bit
EF90	no RS232 start bit received
EF97	received a whole byte, add it to the buffer
EFDB	Routine at EFDB
EFE1	open RS232 channel for output
F014	send byte to the RS232 buffer
F028	setup for RS232 transmit
F04D	input from RS232 buffer
F086	get byte from RS232 buffer
F0A4	check RS232 bus idle
F0BD	kernel I/O messages
F12B	display control I/O message if in direct mode
F13E	get character from the input device
F157	input a character from channel
F199	get byte from tape
F1AD	input device was serial bus
F1B8	input device was RS232 device
F1CA	output character to channel
F1DD	output the character to the cassette or RS232 device
F20E	open channel for input
F250	open channel for output
F291	close a specified logical file
F2EE	serial bus device close
F2F2	close file index X
F30F	find a file
F314	find file A
F31F	set file details from table,X
F32F	close all channels and files
F333	close input and output channels
F34A	open a logical file
F3D5	send secondary address and filename
F409	open RS232 device
F47D	set the top of memory to F0xx
F483	initialise RS232 output
F49E	load RAM from a device
F4A5	load
F533	??
F5AF	print "Searching..."
F5C1	print file name
F5D2	display "LOADING" or "VERIFYING"
F5DD	save RAM to device
F5ED	save
F68F	print saving <file name>
F69B	increment the real time clock
F6DD	read the real time clock
F6E4	set the real time clock
F6ED	scan the stop key
F6FB	file error messages
F72C	find the tape header, exit with header in buffer
F76A	write the tape header
F7D0	get the tape buffer start pointer
F7D7	set the tape buffer start and end pointers
F7EA	find specific tape header
F80D	bump tape pointer
F817	wait for PLAY
F82E	return cassette sense in Zb
F838	wait for PLAY/RECORD
F841	initiate a tape read
F864	initiate a tape write
F875	tape read/write
F8D0	scan stop key and flag abort if pressed
F8DC	clear saved IRQ address
F8E2	set timing
F92C	read tape bits, IRQ routine
FA60	store character
FB8E	copy I/O start address to buffer address
FB97	new tape byte setup
FBA6	send lsb from tape write byte to tape
FBC8	flag block done and exit interrupt
FBCD	tape write IRQ routine
FC6A	write tape leader IRQ routine
FC93	restore everything for STOP
FCB8	reset vector
FCBD	set tape vector
FCCA	stop the cassette motor
FCD1	check read/write pointer
FCDB	increment read/write pointer
FCE2	RESET, hardware reset starts here
FD02	scan for autostart ROM at $8000
FD10	autostart ROM signature
FD15	restore default I/O vectors
FD1A	set/read vectored I/O from (XY)
FD30	kernal vectors
FD50	test RAM and find RAM end
FD9B	tape IRQ vectors
FDA3	initialise SID, CIA and IRQ
FDF9	set filename
FE00	set logical, first and second addresses
FE07	read I/O status word
FE18	control kernal messages
FE1C	OR into the serial status byte
FE21	set timeout on serial bus
FE25	read/set the top of memory
FE27	read the top of memory
FE2D	set the top of memory
FE34	read/set the bottom of memory
FE43	NMI vector
FE47	NMI handler
FE66	user function default vector
FE72	RS232 NMI routine
FEC2	baud rate tables for NTSC C64
FED6	??
FF07	??
FF2E	??
FF41	unused bytes
FF43	save the status and do the IRQ routine
FF48	IRQ vector
FF5B	initialise VIC and screen editor
FF6E	??
FF80	unused
FF81	initialise VIC and screen editor
FF84	initialise SID, CIA and IRQ, unused
FF87	RAM test and find RAM end
FF8A	restore default I/O vectors
FF8D	read/set vectored I/O
FF90	control kernal messages
FF93	send secondary address after LISTEN
FF96	send secondary address after TALK
FF99	read/set the top of memory
FF9C	read/set the bottom of memory
FF9F	scan the keyboard
FFA2	set timeout on serial bus
FFA5	input byte from serial bus
FFA8	output a byte to serial bus
FFAB	command serial bus to UNTALK
FFAE	command serial bus to UNLISTEN
FFB1	command devices on the serial bus to LISTEN
FFB4	command serial bus device to TALK
FFB7	read I/O status word
FFBA	set logical, first and second addresses
FFBD	set the filename
FFC0	open a logical file
FFC3	close a specified logical file
FFC6	open channel for input
FFC9	open channel for output
FFCC	close input and output channels
FFCF	input character from channel
FFD2	output character to channel
FFD5	load RAM from a device
FFD8	save RAM to a device
FFDB	set the real time clock
FFDE	read the real time clock
FFE1	scan the stop key
FFE4	get character from input device
FFE7	close all channels and files
FFEA	increment real time clock
FFED	return X,Y organization of screen
FFF0	read/set X,Y cursor position
FFF3	return the base address of the I/O devices
FFF6	RRBY
FFFA	hardware vectors