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Elite on the BBC Micro

List of all variables [6502SP version]

This index contains every variable that appears in the source code for the 6502 Second Processor version of Elite, grouped by category. A variable is defined as a labelled memory location that is used for storing data, and this list includes both variables that are defined in workspaces, and variables that are declared within the body of the source code.

Copy protection
---------------

copyright (Loader 1)A copyright notice, buried in the code
FirebirdThe name "Firebird", buried in the code of the Executive version

Dashboard
---------

ECBT (I/O processor)The character bitmap for the E.C.M. indicator bulb
SCANparsThe scanner buffer to send with the #onescan command
SPBT (I/O processor)The bitmap definition for the space station indicator bulb

Demo
----

acornThe text for the demo's opening scroll text
byianThe text for the demo's middle scroll text
executiveExtra text for the demo in the Executive version
HIMCNTUsed as a loop counter for the Cobra's slow approach in the demo
LTDEFLine definitions for characters in the Star Wars scroll text
NOFXThe x-coordinates of the scroll text letter grid
NOFYThe y-coordinates of the scroll text letter grid
true3The text for the demo's final scroll text

Drawing lines
-------------

HBUFThe horizontal line buffer to send with the OSWORD 247 command
LBUFThe multi-segment line buffer used by LOIN
LSX2The ball line heap for storing x-coordinates
LSY2The ball line heap for storing y-coordinates
TABLE (I/O processor)The line buffer for line data transmited from the parasite
TWFLReady-made character rows for the left end of a horizontal line in mode 4
TWFRReady-made character rows for the right end of a horizontal line in mode 4

Drawing pixels
--------------

CTWOSReady-made single-pixel character row bytes for mode 5
CTWOS (I/O processor)Ready-made single-pixel character row bytes for mode 2
orange (I/O processor)Lookup table for 2-pixel mode 1 orange pixels for the sun
PBUFThe pixel buffer to send with the OSWORD 241 command
PXCL (I/O processor)A four-colour mode 1 pixel byte that represents a dot's distance
TWFL (I/O processor)Ready-made character rows for the left end of a horizontal line
TWFR (I/O processor)Ready-made character rows for the right end of a horizontal line
TWOSReady-made single-pixel character row bytes for mode 4
TWOS (I/O processor)Ready-made single-pixel character row bytes for mode 1
TWOS (Loader 1)Ready-made single-pixel character row bytes for mode 1
TWOS2Ready-made double-pixel character row bytes for mode 4
TWOS2 (I/O processor)Ready-made double-pixel character row bytes for mode 1
ylookup (I/O processor)Lookup table for converting pixel y-coordinate to page number of screen address

Drawing planets
---------------

CNT (Loader 1)A counter for use in drawing Saturn's planetary body
CNT2 (Loader 1)A counter for use in drawing Saturn's background stars
CNT3 (Loader 1)A counter for use in drawing Saturn's rings
RAND (Loader 1)The random number seed used for drawing Saturn

Drawing ships
-------------

E%Ship blueprints default NEWB flags
scacolShip colours on the scanner
SHIP_ADDERShip blueprint for an Adder
SHIP_ANACONDAShip blueprint for an Anaconda
SHIP_ASP_MK_2Ship blueprint for an Asp Mk II
SHIP_ASTEROIDShip blueprint for an asteroid
SHIP_BOAShip blueprint for a Boa
SHIP_BOULDERShip blueprint for a boulder
SHIP_CANISTERShip blueprint for a cargo canister
SHIP_COBRA_MK_1Ship blueprint for a Cobra Mk I
SHIP_COBRA_MK_3Ship blueprint for a Cobra Mk III
SHIP_COBRA_MK_3_PShip blueprint for a Cobra Mk III (pirate)
SHIP_CONSTRICTORShip blueprint for a Constrictor
SHIP_CORIOLISShip blueprint for a Coriolis space station
SHIP_COUGARShip blueprint for a Cougar
SHIP_DODOShip blueprint for a Dodecahedron ("Dodo") space station
SHIP_ESCAPE_PODShip blueprint for an escape pod
SHIP_FER_DE_LANCEShip blueprint for a Fer-de-Lance
SHIP_GECKOShip blueprint for a Gecko
SHIP_KRAITShip blueprint for a Krait
SHIP_LOGOShip blueprint for the Elite logo
SHIP_MAMBAShip blueprint for a Mamba
SHIP_MISSILEShip blueprint for a missile
SHIP_MORAYShip blueprint for a Moray
SHIP_PLATEShip blueprint for an alloy plate
SHIP_PYTHONShip blueprint for a Python
SHIP_PYTHON_PShip blueprint for a Python (pirate)
SHIP_ROCK_HERMITShip blueprint for a rock hermit (asteroid)
SHIP_SHUTTLEShip blueprint for a Shuttle
SHIP_SIDEWINDERShip blueprint for a Sidewinder
SHIP_SPLINTERShip blueprint for a splinter
SHIP_THARGOIDShip blueprint for a Thargoid mothership
SHIP_THARGONShip blueprint for a Thargon
SHIP_TRANSPORTERShip blueprint for a Transporter
SHIP_VIPERShip blueprint for a Viper
SHIP_WORMShip blueprint for a Worm
shpcolShip colours
XX21Ship blueprints lookup table

Equipment
---------

PRXSEquipment prices

Keyboard
--------

KTRANThe key logger buffer that gets updated by the OSWORD 240 command
KYTBLookup table for in-flight keyboard controls
KYTB (I/O processor)Lookup table for in-flight keyboard controls
TRANTABLETranslation table from internal key number to ASCII

Loader
------

MESS1 (Loader 1)The OS command string for changing the disc directory to E
MESS2 (Loader 1)The OS command string for running the second part of the loader in file ELITEa
MESS2 (Loader 2)The OS command string for running the I/O processor's main game code in file I.CODE
MESS3 (Loader 2)The OS command string for running the parasite's main game code in file P.CODE
RDLIThe OS command string for running the flight code in file D.CODE in the disc version of Elite

Market
------

QQ23Market prices table

Maths (Arithmetic)
------------------

antilogBinary antilogarithm table
antilog (I/O processor)Binary antilogarithm table
antilogODDBinary antilogarithm table
antilogODD (I/O processor)Binary antilogarithm table
logBinary logarithm table (high byte)
log (I/O processor)Binary logarithm table (high byte)
logLBinary logarithm table (low byte)
logL (I/O processor)Binary logarithm table (low byte)

Maths (Geometry)
----------------

ACTArctan table
SNESine/cosine table

Save and load
-------------

CHKFirst checksum byte for the saved commander data file
CHK2Second checksum byte for the saved commander data file
CTLIThe OS command string for cataloguing a disc
DELIThe OS command string for deleting a file
NA%The data block for the last saved commander
oscoblOSFILE configuration block for saving a screenshot
oscobl2Master OSFILE configuration block for saving a screenshot
S1%The drive and directory number used when saving or loading a commander file
scnameFilename to be used when saving a screenshot
stackTemporary storage for the stack pointer when switching the BRKV handler between BRBR and MEBRK

Screen mode
-----------

B% (Loader 1)VDU commands for setting the square mode 1 screen
TVT1 (I/O processor)Palette data for the mode 2 part of the screen (the dashboard)
TVT3 (I/O processor)Palette data for the mode 1 part of the screen (the top part)

Ship hanger
-----------

HATBShip hanger group table

Sound
-----

E% (Loader 1)Sound envelope definitions
SFXSound data
SPEECHPhrases for the Watford Electronics Beeb Speech Synthesiser

Text
----

DTW1A mask for applying the lower case part of Sentence Case to extended text tokens
DTW2A flag that indicates whether we are currently printing a word
DTW3A flag for switching between standard and extended text tokens
DTW4Flags that govern how justified extended text tokens are printed
DTW5The size of the justified text buffer at BUF
DTW6A flag to denote whether printing in lower case is enabled for extended text tokens
DTW8A mask for capitalising the next letter in an extended text token
FONT% (I/O processor)A copy of the character definition bitmap table from the MOS ROM
JMTBThe extended token table for jump tokens 1-32 (DETOK)
MTINLookup table for random tokens in the extended token table (0-37)
printflagA flag that determines whether to send text output to the printer as well as the screen
QQ16The two-letter token lookup table
QQ18The recursive token table for tokens 0-148
RLINEThe OSWORD configuration block used to fetch a line of text from the keyboard
RUGALThe criteria for systems with extended decription overrides
RUPLASystem numbers that have extended decription overrides
RUTOKThe second extended token table for recursive tokens 0-26 (DETOK3)
TENSA constant used when printing large numbers in BPRNT
TKN1The first extended token table for recursive tokens 0-255 (DETOK)
TKN2The extended two-letter token lookup table

Tube
----

JMPTAB (I/O processor)The lookup table for OSWRCH jump commands (128-147)
OSWVECS (I/O processor)The lookup table for OSWORD jump commands (240-255)

Universe
--------

spastoContains the address Coriolis space station's ship blueprint
UNIVTable of pointers to the local universe's ship data blocks

Utility routines
----------------

brkdThe brkd counter for error handling
F%Denotes the end of the main game code, from Elite A to Elite J

Workspace variables
-------------------

ALP1 Magnitude of the roll angle alpha, i.e. |alpha|, which is a positive value between 0 and 31
ALP1 (I/O processor) Magnitude of the roll angle alpha, i.e. |alpha|, which is a positive value between 0 and 31
ALP2 Bit 7 of ALP2 = sign of the roll angle in ALPHA
ALP2 (I/O processor) Bit 7 of ALP2 = sign of the roll angle in ALPHA
ALPHA The current roll angle alpha, which is reduced from JSTX to a sign-magnitude value between -31 and +31
ALTIT Our altitude above the surface of the planet or sun
ALTIT (I/O processor) Our altitude above the surface of the planet or sun
ASH Aft shield status
ASH (I/O processor) Aft shield status
auto Docking computer activation status
AVL Market availability in the current system
BALI The progress of the Star Wars scroll text as it scrolls, from 254 (off the bottom of the screen) to 2 (fully scrolled). Can also be thought of as a measure of how much of the scroll text has yet to appear on-screen
BET1 The magnitude of the pitch angle beta, i.e. |beta|, which is a positive value between 0 and 8
BET1 (I/O processor) The magnitude of the pitch angle beta, i.e. |beta|, which is a positive value between 0 and 8
BET2 Bit 7 of BET2 = sign of the pitch angle in BETA
BETA The current pitch angle beta, which is reduced from JSTY to a sign-magnitude value between -8 and +8
BETA (I/O processor) The current pitch angle beta, which is reduced from JSTY to a sign-magnitude value between -8 and +8
BOMB Energy bomb
BST Fuel scoops (BST stands for "barrel status")
BSTK Bitstik configuration setting
BUF The line buffer used by DASC to print justified text
CABTMP Cabin temperature
CABTMP (I/O processor) Cabin temperature
CASH Our current cash pot
CATF This byte appears to be unused (the CATF variable in the I/O processor code is used to store the CATF flag, not this one)
CATF (I/O processor) The disc catalogue flag
CNT Temporary storage, typically used for storing the number of iterations required when looping
CNT2 Temporary storage, used in the planet-drawing routine to store the segment number where the arc of a partial circle should start
COK Flags used to generate the competition code
COL Temporary storage, used to store colour information when drawing pixels in the dashboard
COL (I/O processor) Temporary storage, used to store colour information when drawing pixels in the dashboard
COMC The colour of the dot on the compass
COMX The x-coordinate of the compass dot
COMY The y-coordinate of the compass dot
CRGO Our ship's cargo capacity
DAMP Keyboard damping configuration setting
de Equipment destruction flag
DELT4 Our current speed * 64 as a 16-bit value
DELTA Our current speed, in the range 1-40
DELTA (I/O processor) Our current speed, in the range 1-40
DJD Keyboard auto-recentre configuration setting
DKCMP Docking computer
DL Vertical sync flag
DL (I/O processor) Vertical sync flag
DLY In-flight message delay
DNOIZ Sound on/off configuration setting
ECM E.C.M. system
ECMA The E.C.M. countdown timer, which determines whether an E.C.M. system is currently operating:
ECMP Our E.C.M. status
ENERGY Energy bank status
ENERGY (I/O processor) Energy bank status
ENGY Energy unit
ESCP Escape pod
ESCP (I/O processor) Escape pod
EV The "extra vessels" spawning counter
FIST Our legal status (FIST stands for "fugitive/innocent status"):
FLAG A flag that's used to define whether this is the first call to the ball line routine in BLINE, so it knows whether to wait for the second call before storing segment data in the ball line heap
FLH Flashing console bars configuration setting
FLH (I/O processor) Flashing console bars configuration setting
FRIN Slots for the ships in the local bubble of universe
FSH Forward shield status
FSH (I/O processor) Forward shield status
GCNT The number of the current galaxy (0-7)
GHYP Galactic hyperdrive
GNTMP Laser temperature (or "gun temperature")
GNTMP (I/O processor) Laser temperature (or "gun temperature")
gov The current system's government type (0-7)
HBUP The size of the horizontal line buffer at HBUF (including the two OSWORD size bytes)
HFX A flag that toggles the hyperspace colour effect
HFX (I/O processor) A flag that toggles the hyperspace colour effect
INF Temporary storage, typically used for storing the address of a ship's data block, so it can be copied to and from the internal workspace at INWK
INWK The zero-page internal workspace for the current ship data block
JSTE Reverse both joystick channels configuration setting
JSTGY Reverse joystick Y-channel configuration setting
JSTK Keyboard or joystick configuration setting
JSTX Our current roll rate
JSTY Our current pitch rate
JUMP Infinite jump range configuration setting
JUNK The amount of junk in the local bubble
K Temporary storage, used in a number of places
K (I/O processor) Temporary storage, used in a number of places
K2 Temporary storage, used in a number of places
K3 Temporary storage, used in a number of places
K3 (I/O processor) Temporary storage, used in a number of places
K4 Temporary storage, used in a number of places
K5 Temporary storage used to store segment coordinates across successive calls to BLINE, the ball line routine
K6 Temporary storage, typically used for storing coordinates during vector calculations
KL The following bytes implement a key logger that enables Elite to scan for concurrent key presses of the primary flight keys, plus a secondary flight key
KY1 "?" is being pressed
KY12 TAB is being pressed
KY13 ESCAPE is being pressed
KY14 "T" is being pressed
KY15 "U" is being pressed
KY16 "M" is being pressed
KY17 "E" is being pressed
KY18 "J" is being pressed
KY19 "C" is being pressed
KY2 Space is being pressed
KY20 "P" is being pressed
KY3 "<" is being pressed
KY4 ">" is being pressed
KY5 "X" is being pressed
KY6 "S" is being pressed
KY7 "A" is being pressed
LAS Contains the laser power of the laser fitted to the current space view (or 0 if there is no laser fitted to the current view)
LAS2 Laser power for the current laser
LASCT The laser pulse count for the current laser
LASER The specifications of the lasers fitted to each of the four space views:
LASX The x-coordinate of the tip of the laser line
LASY The y-coordinate of the tip of the laser line
LBUP The size of the multi-segment line buffer at LBUF
LINMAX (I/O processor) The number of points in the line currently being transmitted from the parasite using the OSWRCH 129 and 130 commands
LINTAB (I/O processor) The offset of the first free byte in the TABLE buffer, which stores bytes in the current line as they are transmitted from the parasite using the OSWRCH 129 and 130 commands
LSO The ship line heap for the space station (see NWSPS) and the sun line heap (see SUN)
LSP The ball line heap pointer, which contains the number of the first free byte after the end of the LSX2 and LSY2 heaps (see the deep dive on "The ball line heap" for details)
LSX LSX is an alias that points to the first byte of the sun line heap at LSO
MANY The number of ships of each type in the local bubble of universe
MCH The text token number of the in-flight message that is currently being shown, and which will be removed by the me2 routine when the counter in DLY reaches zero
MCNT The main loop counter
MCNT (I/O processor) The main loop counter
messXC Temporary storage, used to store the text column of the in-flight message in MESS, so it can be erased from the screen at the correct time
MJ Are we in witchspace (i.e. have we mis-jumped)?
MOS This variable appears to be unused
MSAR The targeting state of our leftmost missile
MSTG The current missile lock target
NAME The current commander name
NEEDKEY Flag to ask the I/O processor to update the key logger buffer at KTRAN
NEWB The ship's "new byte flags" (or NEWB flags)
NOMSL The number of missiles we have fitted (0-4)
NOSTM The number of stardust particles shown on screen, which is 18 (#NOST) for normal space, and 3 for witchspace
OSSC (I/O processor) When the parasite sends an OSWORD command to the I/O processor (i.e. an OSWORD with A = 240 to 255), then the relevant handler routine in the I/O processor is called with OSSC(1 0) pointing to the OSWORD parameter block (i.e. OSSC(1 0) = (Y X) from the original call in the I/O processor)
P Temporary storage, used in a number of places
P (I/O processor) Temporary storage, used in a number of places
P (Loader 1) Temporary storage, used in a number of places
PARAMS (I/O processor) PARAMS points to the start of the dashboard parameter block that is populated by the parasite when it sends the #RDPARAMS and OSWRCH 137 commands
PARANO (I/O processor) PARANO points to the last free byte in PARAMS, which is used as a buffer for bytes sent from the parasite by the #RDPARAMS and OSWRCH 137 commands when updating the dashboard
PATG Configuration setting to show the author names on the start-up screen and enable manual hyperspace mis-jumps
PBUP The size of the pixel buffer at PBUF (including the two OSWORD size bytes)
Q Temporary storage, used in a number of places
Q (I/O processor) Temporary storage, used in a number of places
Q (Loader 1) Temporary storage, used in a number of places
QQ0 The current system's galactic x-coordinate (0-256)
QQ1 The current system's galactic y-coordinate (0-256)
QQ10 The galactic y-coordinate of the crosshairs in the galaxy chart (and, most of the time, the selected system's galactic y-coordinate)
QQ11 The number of the current view:
QQ12 Our "docked" status
QQ14 Our current fuel level (0-70)
QQ14 (I/O processor) Our current fuel level (0-70)
QQ15 The three 16-bit seeds for the selected system, i.e. the one in the crosshairs in the Short-range Chart
QQ17 Contains a number of flags that affect how text tokens are printed, particularly capitalisation:
QQ19 Temporary storage, used in a number of places
QQ2 The three 16-bit seeds for the current system, i.e. the one we are currently in
QQ20 The contents of our cargo hold
QQ21 The three 16-bit seeds for the current galaxy
QQ22 The two hyperspace countdown counters
QQ24 Temporary storage, used to store the current market item's price in routine TT151
QQ25 Temporary storage, used to store the current market item's availability in routine TT151
QQ26 A random value used to randomise market data
QQ28 The current system's economy (0-7)
QQ29 Temporary storage, used in a number of places
QQ3 The selected system's economy (0-7)
QQ4 The selected system's government (0-7)
QQ5 The selected system's tech level (0-14)
QQ6 The selected system's population in billions * 10 (1-71), so the maximum population is 7.1 billion
QQ7 The selected system's productivity in M CR (96-62480)
QQ8 The distance from the current system to the selected system in light years * 10, stored as a 16-bit number
QQ9 The galactic x-coordinate of the crosshairs in the galaxy chart (and, most of the time, the selected system's galactic x-coordinate)
R Temporary storage, used in a number of places
R (I/O processor) Temporary storage, used in a number of places
RAND Four 8-bit seeds for the random number generation system implemented in the DORND routine
RAT Used to store different signs depending on the current space view, for use in calculating stardust movement
RAT2 Temporary storage, used to store the pitch and roll signs when moving objects and stardust
S Temporary storage, used in a number of places
S (I/O processor) Temporary storage, used in a number of places
safehouse Backup storage for the seeds for the selected system
SC Screen address (low byte)
SC (I/O processor) Screen address (low byte)
SCH Screen address (high byte)
SCH (I/O processor) Screen address (high byte)
SLSP The address of the bottom of the ship line heap
SPEAK Speech configuration setting
SSPR "Space station present" flag
STP The step size for drawing circles
SUNX The 16-bit x-coordinate of the vertical centre axis of the sun (which might be off-screen)
SVC The save count
svn (I/O processor) "Saving in progress" flag
SWAP Temporary storage, used to store a flag that records whether or not we had to swap a line's start and end coordinates around when clipping the line in routine LL145 (the flag is used in places like BLINE to swap them back)
SWAP (I/O processor) Temporary storage, used to store a flag that records whether or not we had to swap a line's start and end coordinates around when clipping the line in routine LL145 (the flag is used in places like BLINE to swap them back)
SX This is where we store the x_hi coordinates for all the stardust particles
SXL This is where we store the x_lo coordinates for all the stardust particles
SY This is where we store the y_hi coordinates for all the stardust particles
SYL This is where we store the y_lo coordinates for all the stardust particles
SZ This is where we store the z_hi coordinates for all the stardust particles
SZL This is where we store the z_lo coordinates for all the stardust particles
T Temporary storage, used in a number of places
T (I/O processor) Temporary storage, used in a number of places
T (Loader 1) Temporary storage, used in a number of places
T1 Temporary storage, used in a number of places
T1 (I/O processor) Temporary storage, used in a number of places
TALLY Our combat rank
tek The current system's tech level (0-14)
TGT Temporary storage, typically used as a target value for counters when drawing explosion clouds and partial circles
TP The current mission status
TYPE The current ship type
U Temporary storage, used in a number of places
U (I/O processor) Temporary storage, used in a number of places
UPO Used as an index into the UB tables when projecting the scroll text lines onto the Star Wars perspective view and then onto the screen
V Temporary storage, typically used for storing an address pointer
VEC (I/O processor) VEC = &7FFE
VIEW The number of the current space view
widget Temporary storage, used to store the original argument in A in the logarithmic FMLTU and LL28 routines
X1 Temporary storage, typically used for x-coordinates in line-drawing routines
X1 (I/O processor) Temporary storage, typically used for x-coordinates in line-drawing routines
X1TB The x-coordinates of the start points for character lines in the scroll text (as space coordinates)
X1UB The x-coordinates of the start points for character lines in the scroll text (as projected screen coordinates)
X1VB The x-coordinates of the start points for the previous set of character lines in the scroll text (as projected screen coordinates) so they can be erased
X2 Temporary storage, typically used for x-coordinates in line-drawing routines
X2 (I/O processor) Temporary storage, typically used for x-coordinates in line-drawing routines
X2TB The x-coordinates of the end points for character lines in the scroll text
X2UB The x-coordinates of the end points for character lines in the scroll text (as projected screen coordinates)
X2VB The x-coordinates of the end points for the previous set of character lines in the scroll text (as projected screen coordinates) so they can be erased
XC The x-coordinate of the text cursor (i.e. the text column), which can be from 0 to 32
XC (I/O processor) The x-coordinate of the text cursor (i.e. the text column), set to an initial value of 1
XP The x-coordinate of the current character as we construct the lines for the Star Wars scroll text
XSAV Temporary storage for saving the value of the X register, used in a number of places
XSAV2 This byte appears to be unused
XX Temporary storage, typically used for storing a 16-bit x-coordinate
XX0 Temporary storage, used to store the address of a ship blueprint. For example, it is used when we add a new ship to the local bubble in routine NWSHP, and it contains the address of the current ship's blueprint as we loop through all the nearby ships in the main flight loop
XX1 This is an alias for INWK that is used in the main ship-drawing routine at LL9
XX12 Temporary storage for a block of values, used in a number of places
XX13 Temporary storage, typically used in the line-drawing routines
XX14 This byte appears to be unused
XX15 Temporary storage, typically used for storing screen coordinates in line-drawing routines
XX15 (I/O processor) Temporary storage, typically used for storing screen coordinates in line-drawing routines
XX16 Temporary storage for a block of values, used in a number of places
XX17 Temporary storage, used in BPRNT to store the number of characters to print, and as the edge counter in the main ship-drawing routine
XX18 Temporary storage used to store coordinates in the LL9 ship-drawing routine
XX19 XX19(1 0) shares its location with INWK(34 33), which contains the address of the ship line heap
XX2 Temporary storage, used to store the visibility of the ship's faces during the ship-drawing routine at LL9
XX20 Temporary storage, used in a number of places
XX24 This byte appears to be unused
XX4 Temporary storage, used in a number of places
Y1 Temporary storage, typically used for y-coordinates in line-drawing routines
Y1 (I/O processor) Temporary storage, typically used for y-coordinates in line-drawing routines
Y1TB The y-coordinates of the start points for character lines in the scroll text
Y1UB The y-coordinates of the start points for character lines in the scroll text (as projected screen coordinates)
Y1VB The y-coordinates of the start points for the previous set of character lines in the scroll text (as projected screen coordinates) so they can be erased
Y2 Temporary storage, typically used for y-coordinates in line-drawing routines
Y2 (I/O processor) Temporary storage, typically used for y-coordinates in line-drawing routines
Y2TB The y-coordinates of the end points for character lines in the scroll text
Y2UB The y-coordinates of the end points for character lines in the scroll text (as projected screen coordinates)
Y2VB The y-coordinates of the end points for the previous set of character lines in the scroll text (as projected screen coordinates) so they can be erased
YC The y-coordinate of the text cursor (i.e. the text row), which can be from 0 to 23
YC (I/O processor) The y-coordinate of the text cursor (i.e. the text row), set to an initial value of 1
YP The y-coordinate of the current character as we construct the lines for the Star Wars scroll text
YS Temporary storage for saving the index into the TB tables in the SLIDE routine
YSAV Temporary storage for saving the value of the Y register, used in a number of places
YSAV (I/O processor) Temporary storage for saving the value of the Y register, used in a number of places
YSAV2 This byte appears to be unused
YY Temporary storage, typically used for storing a 16-bit y-coordinate
YY (Loader 1) Temporary storage, used in a number of places
Z1 (Loader 2) Temporary storage, used when moving code
Z2 (Loader 2) Temporary storage, used when moving code
ZIP This label is not used but is in the original source
ZZ Temporary storage, typically used for distance values