Commando

Routines

Address	Description
6400	Block of redirects
6456	Trigger sound effect A (copy its parameter into slot A)
6469	Clear 7 bytes at $6433
6474	Sound-effect dispatcher, 7 channels
6495	Decay sound-effect counters at $6433
64AB	Play a two-stage sound stepped by counter $6434
64C7	Play beep tone (pitch $6437, duration loop)
64E9	Play a beep with pitch derived from $6438
64F9	Play a beep with pitch derived from $6439
6505	Play a beep with pitch derived from $6436
650F	Play a banded sound stepped by counter $6435
6533	Play a sound-effect tone (pitch from $6433)
6550	Unreferenced duplicate of the beeper loop at 6575
6575	Sound a square-wave beep
6593	Scan $6648 table, call $65A5 for active entries
65A5	Tick an object's timer; when it runs out, rebuild its work record
65F6	Menu key check, set carry/B=$12 (unconfirmed)
6600	Find free slot in $6648 table
6626	Prepare records and variables at $6648
6751	Set up scrolling string
676B	Scroll the message banner one pixel left
679D	Advance scroll-message pointer, copy next char's font row to $681E
6825	Update Score
6896	Convert (H,L) screen coords to screen address
68A6	Zero screen rows using SP as pointer (B rows)
68CA	Screen wipe/reveal transition, paced by $FDBC
6950	Compute row attribute address, call $69B4
6975	Fill status-bar columns down, calling $699A per column
699A	Compute attribute address for fixed tile row
69B4	Compute attribute address for tile (D,E)
69D2	Set up attract/menu mode, then fall into the main menu
69F3	Main menu: show score table, dispatch menu key
6A1E	Redefine Keys
6A8C	Check if a key code is already assigned (Redefine Keys)
6AE1	Prepare status bar screen: fill, set scroll handler
6B14	Wait key unpress, wait key press
6B21	Clear playfield and status screen/attribute areas
6B4C	Zero rectangle at HL (C rows x B bytes)
6B87	Draw menu box border/frame
6BAC	Scroll the Area in, up to $5C steps or until it arrives
6BBB	Start Game
6C7A	We've got A more grenades
6C80	Update grenades number on the screen
6C96	Print Area number
6C99	Print 2-digit number A
6CAE	Game Over
6E08	Name entry finished: wait for the key to lift, clear the screen and return to the menu
6E11	Print table row using $6E34
6E34	Print char with derived attribute
6E7B	Update the Top Score name-entry selectors
6ECD	Draw/move the Top Score name-entry cursor
6F1D	Name-entry outro: draw selectors, animate, clear
6F46	Prepare records at $6FE5
6F52	Look up record in $6FE5 table, mask low bits
6F79	Find free record in table at $6FD9
6FC7	Prepare records at $6FD9
6FF5	Advance strip position, scroll the $6711 tile buffer
706E	Unpack $66D1 record, scale coordinate x4
70BD	XOR attribute pattern onto screen, explosion effect
70EC	Copy 64 bytes $66D1 to $6711
70F8	Find a place in Top Score table
7143	Select joystick type
71A8	Print string HL
71B6	Print credits screen, scroll text into $5923 area
7251	Check menu keys
725D	Print immediate string checking menu keys
7274	Print Score Table
7357	Game main loop / frame handler
73B7	Read Keyboard
7405	Compute code checksum
7511	XOR AF and AF' with every byte in $F900-F9FF
7547	Read input: joystick or keyboard
7563	Read the Kempston joystick from port $1F
7569	Read Interface II: scan its port and mask list
757A	Read the Fuller joystick from port $7F
7587	Read the cursor keys: scan their port and mask list
75A8	Read keyboard in game mode
75BE	Fill screen rectangle with byte
75D2	Print key entered on Redefine Keys
7615	Print immediate string
7621	Print HL as 4-digit hex/BCD
7637	Print Char
7767	Char $02: set spacing/mode ($FDB1) from arg, range 0-3
777A	Char $00: clear screen (attributes + bitmap)
7795	Fill all screen attributes with D
77A4	Char $04: advance format counter by 2, store fill char
77A8	Char $0D: store the fill char at HL
77AC	Char $0A: increment format counter, abort if it reaches $31
77B8	Char $0B: decrement format counter, abort on underflow
77C2	Char $08: decrement format counter, abort if negative
77CB	Char $09: increment format counter, store fill char once $20 reached
77D5	Char $12: set/clear bit 6 of $FDA0 from arg (0/1)
77EB	Char $19: set/clear flag bit 0 ($FDAF) from arg
77FD	Char $10: set field bits 0-2 of $FDA0 from arg
7811	Char $11: set field bits 3-5 of $FDA0 from arg
7828	Char $16: set print position, 2 bounds-checked args
783E	Char $03: repeat character H, L times
784A	Char $13: set fill char ($FD9F) from arg
7852	Char $14: set tab stop, advance format counter
7866	Char $1A: set Font address ($FDA3) from arg word
786E	Char $0C: print padded field using $FDB0 width
787F	Char $18: set width/column counter ($FDB0) from arg
7887	Char $15: set/clear flag bit 1 ($FDAF) from arg
7896	Char $01: reset print format state
78BF	-> $7A10
78C2	Print opcode exit: drop two saved register pairs
78C4	Print opcode exit: drop the saved state and return
78C7	Print opcode exit: drop the saved registers and return
792C	Prepare at new Area
796A	Prepare New Game
79CA	System init: interrupt table, screen-line table, checksums
79E1	Init $FF00 buffer entries (32 slots, unconfirmed)
79FB	Build the $FA00 column-checksum table
7A10	Abort: restore stack and interrupts, return to frame loop
7A1E	Set up interrupt vector table at $FB00
7A42	Game main loop / frame handler (redirect)
7A45	Prepare $FE00 table - addresses for every even screen line
7A5C	Delay by BC HALTs
8000	Entry point: jump to the redirect block, and the base of the checksummed region
8003	Advance level scroll: walk $FF00 buffer, process sequence record (redirect)
8006	Clear the draw-mode flag (R bit 7), enter $9193 (redirect)
8009	Redirect: jump to the level-1 sequence table
800C	Multiply HL by 10, add DE (redirect)
800F	Mark map cells for object IX, direction-aware (redirect)
8062	End of the enemy run with rocket launchers
806B	Mark map cells for object IX, direction-aware
80E4	Mark 3 cells in $1600 map, B=1 (entry to $80ED)
80EA	Mark 3 cells in $1600 map, B=C (entry to $80ED)
80FB	Mark cells in $1600 map, B=1 (entry to $8104)
8101	Mark cells in $1600 map, B=C (entry to $8104)
8122	Set/test flag in $1600 map at tile (D,E)
8158	Turn the alarm on: sound it, then draw
8164	Draw a trench, right-hand side
8169	Draw a trench, left-hand side
8178	Draw a trench, middle
8187	Spawn point marker: the Area replays from here
818F	Draw the fortress gates
822B	Move and draw a prisoner of war
82C1	Set object state flags, call $806B
82E1	Advance/rotate object buffer pointer
8301	Draw a small hut
832F	Draw the cave body
833F	Draw a cave top edge
8344	Draw a cave bottom edge
834B	Draw sprite HL
83A4	Spawn the Jeep: seed its record at $FDCB
83B8	Update and draw the Jeep sprite
8458	Set the type of the next motorbike
8471	Run both motorbikes: prepare, animate and draw
8497	Animate and draw a motorbike
8500	Prepare the motorbike sprite: reload or shift one pixel
854A	Sprite draw dispatch: clip and compute screen address
8594	Draw the truck
85AB	Update and draw the Truck(s)
8618	Draw two-part sprite from record at HL
867C	Clip sprite rectangle against screen edge (vertical)
86B8	Get Truck sprite to $6300 buffer and shift it if needed
86F5	Draw a bunker
872F	Draw the road surface on a bridge
876E	Draw a wall
87F1	Draw a bridge section
88FD	Draw a barracks
8914	Draw a tunnel
896D	Get attributes address for the screen line
897F	Draw a log crossing
899E	Compute screen draw address for sprite, save state to buffer
89F3	Set attribute color for B cells at HL
8A03	Set attribute INK=1 for B cells at HL (variant of $89F3)
8A14	Sprite draw dispatch variant, C=4
8A7B	Sprite draw dispatch: clip and compute screen address, C=$08
8AC3	Sprite draw dispatch: clip and compute screen address, C=$0C
8B4B	Sprite draw dispatch: clip and compute screen address, C=$10
8BE7	Sprite draw dispatch: clip and compute screen address, C=$14
8CC9	Clip sprite, then AND/OR-mask blit rows via SP into screen
8D58	Draw water strip 1
8D5D	Draw water strip 2
8D8D	Draw the structure's extra segment when the sub-row index calls for it
8D9E	Draw one segment of the structure and colour the row beneath it
8DCC	Draw water
8E35	Fill a block of screen rows with the DE and BC patterns through the stack
8E51	Fold the screen address into the attribute area and colour the cells
8E74	Draw a left mortar
8E83	Draw a right mortar
8E92	Shift-add multiply: 8 bits of H, adding DE per set bit
8EB5	A single grenade pickup
8ECC	A triple grenade pickup
8EE3	A quintuple grenade pickup
8F17	Draw sandbags, left-hand side
8F26	Draw sandbags, middle
8F35	Draw sandbags, right-hand side
8F42	Draw the road bottom edging
8F49	Draw the road top edging
9005	Draw a road marking
9014	Draw a tree
903E	Draw a boulder
904D	Draw a cliff edge
90A1	Adjust and clip sprite draw, calls $8A14
90AC	Draw a mirrored cliff
9132	Decrement Land space or process next record in the sequence
9176	Level record: abort the sequence through the redirect block
917C	Walk $FF00 buffer chain (offset $FD88), increment field at +4
9193	Advance level scroll: walk $FF00 buffer, process sequence record
91E3	Link record entry into the $FF00 buffer chain, continue
9204	Process record codes $01-28, not $22
921F	Insert entry into $FF00 buffer chain
98D0	Update object IX position, clip to screen, dispatch sprite draw (redirect)
98D3	HL = HL + A (redirect)
98D6	(HL) -> HL (redirect)
98D9	Convert row number to screen line address (redirect)
98DC	DOWN HL (redirect)
98DF	UP HL (redirect)
98EA	HL = HL + A
98F0	(HL) -> HL
98F5	Convert row number to screen line address (via $FE00 table)
9904	DOWN HL - move HL to the next screen line
9913	UP HL
9922	Update object IX position, clip to screen, dispatch sprite draw
9A46	Blit continuation: draw remaining sprite width
9A6E	Clip sprite edge, dispatch to masked blit
9AE6	Clip wide sprite edge, dispatch to masked blit
9B05	Masked blit: four-column band, serpentine
9B61	Set up sprite erase, dispatch to erase-blit variant
9B97	Second pass: redraw sprite via unmasked-OR blit
9BCB	Set up sprite erase (positive path), dispatch to erase-blit
9BF5	Second pass (positive path): redraw via unmasked-OR blit
9C23	Compute screen address for sprite row via IX object
9C6B	Erase sprite: AND-mask bytes off screen, SP walks data as pointer
9CB1	Erase sprite: AND-mask bytes off screen, SP walks data as pointer
9CED	Erase sprite variant: AND-mask 2 bytes per column via SP
9D1F	Erase sprite: AND-mask bytes off screen, SP walks data as pointer
9D5B	Erase sprite variant: AND-mask row bytes via SP
9D8D	Unmasked-OR blit variant, draws opaque sprite row across screen thirds
9DCC	Unmasked-OR blit variant: 2 bytes per column via SP
9E03	Unmasked-OR blit variant: one column, 2 lines per pass
9E32	Unmasked-OR blit variant: two columns, serpentine
9E69	Unmasked-OR blit variant: alternating columns via SP
9E98	Masked-OR blit variant, draws sprite row across screen thirds
9EDF	Unmasked-OR blit, draws opaque sprite row across screen thirds
9F1D	Off-screen sprite draw: clip, compute address, dispatch blit
9FDE	Finish sprite off-screen: commit pending fields
9FF5	Blit finish: commit Y position, restore SP
DC83	Get random byte (redirect)
DC86	Entry E=0, dispatch bullet/collision handler via $DF39 (redirect)
DC89	Initialization and go to game main loop (redirect)
DC8C	Check IX flag and column bound, dispatch (redirect)
DC8F	Check screen brightness threshold, inside $DD8D (redirect)
DC92	Entry E=2, dispatch bullet/collision handler via $DF39 (redirect)
DC95	Scroll level and shift all objects down
DCAF	Periodically spawn a new enemy from the edge
DCDF	Initialization and go to game main loop
DD71	Process object records at $5B11
DD89	Process Player's object record
DD8D	Draw object IX: select sprite frame, clip, blit
DE91	Game's main loop, Part 1
DEDD	Wait for the pause key to be released, pressed and released again
DEEF	Game's main loop, Part 2
DF16	Random number generator: step the 32-bit register at $FD9B
DF33	Entry E=2, dispatch bullet/collision handler via $DF39
DF37	Entry E=0, dispatch bullet/collision handler via $DF39
DF67	Collision scan exit: restore SP and report no hit
DF6D	Collision scan: drop this entry and take the next
DF71	Collision hit on the player: flag them dead and mark the object
DF7B	Bullet collision check, carry set on hit
E01B	Check IX flag and column bound, dispatch
E0BF	Map-scan tails: step to the next row, or set the Area flag and return
E100	Set up player object pointers (IX=$5BDA) (redirect)
E103	Check fire button and joystick input (redirect)
E106	Check player shots against every enemy in $5B11 (redirect)
E109	Rebuild active-object list at $F900 from $FF00 buffer (redirect)
E10C	Decrement Enemy delay ($FDDD), spawn enemy by Area ($FDE5) when due (redirect)
E10F	Find free enemy slot in $5B11 table, inside $E01B (redirect)
E112	Draw a small random offset (-1, 0 or +1) (redirect)
E1A8	Tail of the AI table block: drop the return address and abort
E1AC	Draw a small random offset (-1, 0 or +1)
E1B5	Service the two bomb/explosion slots
E1D1	Check pickup/collision near object, award score
E224	Jeep hit check, kill/score, spawn next enemy (unconfirmed)
E2DD	Init enemy object (BC=$0806, type $07)
E2EA	Decrement Enemy delay ($FDDD), spawn enemy by Area ($FDE5) when due
E4FC	Set up player object pointers (IX=$5BDA)
E5B8	Convert direction code (masked 0-15) to E delta
E5DB	Move enemy toward target, clamp to bounds
E628	Dispatch by direction, clear draw-active if off-screen
E648	Move right: check keys/state, advance E and wrap
E679	Move left: check keys/state, advance E and wrap
E6A8	Move enemy up one row if states/flags allow
E6DB	Move up/down: check states, adjust row
E6FE	Check player shots against every enemy in $5B11
E77C	Scan object table for entry near position
E794	Enemy melee/contact check vs player, kill if close
E86B	Enemy AI pause: reload short action timer
E881	Enemy AI: re-aim at player, random fire
E8A0	Enemy wandering AI: timed re-aim, random fire and step
E90A	Enemy AI: check row range, transition to attack state
E972	Dispatch enemy AI by state (IX+$12)
E9C7	Enemy AI state: clear the turn flag, reset the state and wander
E9D2	Enemy AI state: clear the turn flag, wait $30 frames
E9DD	Enemy AI state: pick a heading by row band, or fire
EA8E	Enemy AI state: count the turn timer down, then steer
EB13	Set enemy AI delay/direction by Area number ($FDE5)
EB68	Enter enemy AI state $01 with heading $08
EB7B	Enemy patrol AI: walk N steps then reverse
EB96	Enemy AI: wander or chase player by aggressive flag
EBE1	Compute direction bits toward player position
EC1B	Check enemy position on-screen, trigger action
EC58	Set enemy sub-state (IX+$0C) by threshold, reset delay/target
ECC1	Check fire button and joystick input
ED31	Look up entry in table at $EC81
ED52	Rebuild active-object list at $F900 from $FF00 buffer
EDC8	Populate object record fields from A/B and a source byte
EDD6	Init object timer field via $EDC8
EE11	Read the scroll value from the record and store it
EE15	Seed the scroll position from the record when it is unset
EE24	Advance the record fields and stamp the object onto the map
EF37	Init object record via $EDC8, entry size $0E