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117 lines
6.2 KiB
ArmAsm
117 lines
6.2 KiB
ArmAsm
; Tile storage parameters
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TILE_DATA_SPAN equ 4
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TILE_STORE_WIDTH equ 41
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TILE_STORE_HEIGHT equ 26
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MAX_TILES equ {26*41} ; Number of tiles in the code field (41 columns * 26 rows)
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TILE_STORE_SIZE equ {MAX_TILES*2} ; The tile store contains a tile descriptor in each slot
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TS_TILE_ID equ TILE_STORE_SIZE*0 ; tile descriptor for this location
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TS_DIRTY equ TILE_STORE_SIZE*1 ; Flag. Used to prevent a tile from being queued multiple times per frame
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TS_SPRITE_FLAG equ TILE_STORE_SIZE*2 ; Bitfield of all sprites that intersect this tile. 0 if no sprites.
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TS_TILE_ADDR equ TILE_STORE_SIZE*3 ; cached value, the address of the tiledata for this tile
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TS_CODE_ADDR_LOW equ TILE_STORE_SIZE*4 ; const value, address of this tile in the code fields
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TS_CODE_ADDR_HIGH equ TILE_STORE_SIZE*5
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TS_WORD_OFFSET equ TILE_STORE_SIZE*6 ; const value, word offset value for this tile if LDA (dp),y instructions re used
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TS_BASE_ADDR equ TILE_STORE_SIZE*7 ; const value, because there are two rows of tiles per bank, this is set to $0000 ot $8000.
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TS_SCREEN_ADDR equ TILE_STORE_SIZE*8 ; cached value of on-screen location of tile. Used for DirtyRender.
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;TS_VBUFF_ARRAY_ADDR equ TILE_STORE_SIZE*9 ; const value to an aligned 32-byte array starting at $8000 in TileStore bank
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TS_BASE_TILE_COPY equ TILE_STORE_SIZE*9 ; derived from TS_TILE_ID to optimize tile copy to support sprite rendering
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TS_BASE_TILE_DISP equ TILE_STORE_SIZE*10 ; derived from TS_TILE_ID to optimize base (non-sprite) tile dispatch in the Render function
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TS_DIRTY_TILE_DISP equ TILE_STORE_SIZE*11 ; derived from TS_TILE_ID to optimize dirty tile dispatch in the Render function
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; Hold values for up to 4 sprites per tile
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TS_VBUFF_ADDR_0 equ TILE_STORE_SIZE*12
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TS_VBUFF_ADDR_1 equ TILE_STORE_SIZE*13
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TS_VBUFF_ADDR_2 equ TILE_STORE_SIZE*14
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TS_VBUFF_ADDR_3 equ TILE_STORE_SIZE*15
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TS_VBUFF_ADDR_COUNT equ TILE_STORE_SIZE*16 ; replace usage of TS_VBUFF_ARRAY_ADDR with this later
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; Sprite data structures. We cache quite a few pieces of information about the sprite
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; to make calculations faster, so this is hidden from the caller.
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MAX_SPRITES equ 16
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SPRITE_REC_SIZE equ 52
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; Mark each sprite as ADDED, UPDATED, MOVED, REMOVED depending on the actions applied to it
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; on this frame. Quick note, the same Sprite ID cannot be removed and added in the same frame.
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; A REMOVED sprite if removed from the sprite list during the Render call, so it's ID is not
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; available to the AddSprite function until the next frame.
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SPRITE_STATUS_EMPTY equ $0000 ; If the status value is zero, this sprite slot is available
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SPRITE_STATUS_OCCUPIED equ $8000 ; Set the MSB to flag it as occupied
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SPRITE_STATUS_ADDED equ $0001 ; Sprite was just added (new sprite)
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SPRITE_STATUS_MOVED equ $0002 ; Sprite's position was changed
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SPRITE_STATUS_UPDATED equ $0004 ; Sprite's non-position attributes were changed
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SPRITE_STATUS_REMOVED equ $0008 ; Sprite has been removed.
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SPRITE_STATUS equ {MAX_SPRITES*0}
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; TILE_DATA_OFFSET equ {MAX_SPRITES*2}
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VBUFF_ADDR equ {MAX_SPRITES*4} ; Base address of the sprite's stamp in the data/mask banks
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SPRITE_ID equ {MAX_SPRITES*6}
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SPRITE_X equ {MAX_SPRITES*8}
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SPRITE_Y equ {MAX_SPRITES*10}
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; TILE_STORE_ADDR_1 equ {MAX_SPRITES*12}
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TS_LOOKUP_INDEX equ {MAX_SPRITES*12} ; The index into the TileStoreLookup table corresponding to the top-left corner of the sprite
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; TILE_STORE_ADDR_2 equ {MAX_SPRITES*14}
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TS_COVERAGE_SIZE equ {MAX_SPRITES*14} ; Index into the lookup table of how many TileStore tiles are covered by this sprite
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;TILE_STORE_ADDR_3 equ {MAX_SPRITES*16}
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TS_VBUFF_BASE_ADDR equ {MAX_SPRITES*16} ; Fixed address of the TS_VBUFF_X memory locations
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;TILE_STORE_ADDR_4 equ {MAX_SPRITES*18}
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;TILE_STORE_ADDR_5 equ {MAX_SPRITES*20}
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;TILE_STORE_ADDR_6 equ {MAX_SPRITES*22}
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;TILE_STORE_ADDR_7 equ {MAX_SPRITES*24}
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;TILE_STORE_ADDR_8 equ {MAX_SPRITES*26}
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;TILE_STORE_ADDR_9 equ {MAX_SPRITES*28}
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;TILE_STORE_ADDR_10 equ {MAX_SPRITES*30}
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SPRITE_DISP equ {MAX_SPRITES*32} ; cached address of the specific stamp based on flags
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SPRITE_CLIP_LEFT equ {MAX_SPRITES*34}
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SPRITE_CLIP_RIGHT equ {MAX_SPRITES*36}
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SPRITE_CLIP_TOP equ {MAX_SPRITES*38}
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SPRITE_CLIP_BOTTOM equ {MAX_SPRITES*40}
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IS_OFF_SCREEN equ {MAX_SPRITES*42}
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SPRITE_WIDTH equ {MAX_SPRITES*44}
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SPRITE_HEIGHT equ {MAX_SPRITES*46}
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SPRITE_CLIP_WIDTH equ {MAX_SPRITES*48}
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SPRITE_CLIP_HEIGHT equ {MAX_SPRITES*50}
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; 50 rows by 80 columns + 2 extra rows and columns
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TS_LOOKUP_WIDTH equ 80
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TS_LOOKUP_HEIGHT equ 50
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TS_LOOKUP_SPAN equ {TS_LOOKUP_WIDTH+2}
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TS_LOOKUP_ROWS equ {TS_LOOKUP_HEIGHT+2}
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; Blitter template constancts
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PER_TILE_SIZE equ 3
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SNIPPET_SIZE equ 32
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;----------------------------------------------------------------------
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;
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; Timer implementation
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;
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; The engire provides four timer slot that can be used by one-shot or
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; recurring timers. Each timer is given an initial tick count, a
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; reset tick count (0 = one-shot), and an action to perform.
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;
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; The timers handle overflow, so if a recurring timer has a tick count of 3
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; and 7 VBL ticks have passed, then the timer will be fired twice and
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; a tick count of 2 will be set.
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;
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; As such, the timers are appropriate to drive physical and other game
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; behaviors at a frame-independent rate.
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;
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; A collection of 4 timers that are triggered when their countdown
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; goes below zero. Each timer takes up 16 bytes
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;
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; A timer can fire multiple times during a singular evaluation. For example, if the
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; timer delay is set to 1 and 3 VBL ticks happen, then the timer delta is -2, will fire,
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; have the delay added and get -1, fire again, increment to zero, first again and then
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; finally reset to 1.
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;
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; +0 counter decremented by the number of ticks since last run
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; +2 reset copied into counter when triggered. 0 turns off the timer.
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; +4 addr long address of timer routine
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; +8 user 8 bytes of user data space for timer state
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MAX_TIMERS equ 4
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TIMER_REC_SIZE equ 16
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