mirror of
https://github.com/lscharen/iigs-game-engine.git
synced 2024-09-28 11:54:40 +00:00
Improving initialization of code fields
This commit is contained in:
Lucas Scharenbroich
parent
9137440d41
commit
7e6c4a0c91
@ -75,17 +75,18 @@ SHR_SCB equ $E19D00
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; Start up the graphics engine...
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jsr MemInit
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jsr GrafInit
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jsr MemInit ; Allocate memory
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jsr BlitInit ; Initialize the memory
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jsr GrafInit ; Initialize the graphics screen
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]step equ 0
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lup 13
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ldx #BlitBuff
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lda #^BlitBuff
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ldy #]step
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jsr BuildBank
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]step equ ]step+4
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--^
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lda #16*256+28 ; Place the playfield at (16, 28) with
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ldx #128 ; a width of 128 bytes (256 pixels) and
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ldy #144 ; 144 scan lines
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jsr SetScreenRect
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lda #0 ; Set the virtual Y-position
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jsr SetYPos
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brl Exit
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; Load a picture and copy it into Bank $E1. Then turn on the screen.
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@ -107,31 +108,6 @@ EvtLoop
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brl DoFrame
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:4 bra EvtLoop
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; Set the screen address (right-edge) in all of the scan lines
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SetRightEdge
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sep #$20 ; push all the bank addresses on the stack
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ldx #0
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:loop1 lda BlitBuff+2,x
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pha
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inx
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inx
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inx
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inx
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cpx #4*13
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bcc :loop1
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lup 13
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lda #{$2000+159+15*160} ; Set the stack address to the right edge of the screen
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ldy #0
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ldx #16*2
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jsr SetScreenAddrs
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--^
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phk
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plb
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rts
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; Set up the code field and render it
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DoFrame
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@ -213,10 +189,10 @@ DoFrame
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ldx #16*2
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jsr SetConst
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lda #{$2000+159+15*160} ; Set the stack address to the right edge of the screen
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ldy #0
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ldx #16*2
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jsr SetScreenAddrs
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; lda #{$2000+159+15*160} ; Set the stack address to the right edge of the screen
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; ldy #0
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; ldx #16*2
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; jsr SetScreenAddrs
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sep #$20 ; only need to do an 8-bit store
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lda #$06 ; This is the entry address to start drawing
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@ -418,9 +394,20 @@ VBLTASK hex 00000000
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dw 0
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hex 5AA5
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; Blitter initialization
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BlitInit
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]step equ 0
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lup 13
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ldx #BlitBuff
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lda #^BlitBuff
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ldy #]step
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jsr BuildBank
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]step equ ]step+4
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--^
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rts
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; Graphic screen initialization
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GrafInit lda #$8888
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jsr ClearToColor
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lda #0000
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@ -635,3 +622,17 @@ qtRec adrl $0000
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put blitter/Tables.s
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@ -8,6 +8,8 @@ ScreenX1 equ 10
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StartY equ 12 ; Which code buffer line displays first on screen. Range = 0 to 207
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bstk equ 224 ; 16-byte stack to push bank addresses
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tmp0 equ 240 ; 16 bytes of temporary space to be used as scratch
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tmp1 equ 242
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tmp2 equ 244
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@ -18,3 +20,5 @@ tmp6 equ 252
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tmp7 equ 254
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@ -104,7 +104,7 @@ SetScreenRect sty ScreenHeight ; Save the screen height a
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rts
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; Set the starting line of the virtual buffer that will be displayed on the first physical line
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; of the screen rect.
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; of the playfield.
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;
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; A = line number [0, 207]
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;
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@ -149,39 +149,35 @@ SetScreenRect sty ScreenHeight ; Save the screen height a
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; if (line_count > 0) {
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; do_action(curr_bank, 0, line_count)
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; }
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;
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; One hack we do is to push in *at least* enough bank values (ScreenHeight / 16) + 1 on the
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; stack ahead of time and just pop them off in order. At worst, this only adds about 10 cycles
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; of overhead and eliminates an awkward 16-bit <-> 8-bit state switch within the inner loops.
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;
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bank_count equ tmp0
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start_mod_16 equ tmp1
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line_x2 equ tmp2 ; A physical screen line; used to index into RTable
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last_x2 equ tmp3
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start_mod_16 equ tmp0
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lines_left equ tmp1
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tblptr equ tmp2
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stksave equ tmp7
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SetYPos sta StartY ; Save the position
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asl
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sta line_x2
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lsr
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; First action is to calculate the number of code banks that we will be updating and push all of the
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; bank bytes onto the stack in order so that we can use a single 'plb' instruction to set the target
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; for updating the screen address of each blitter line.
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; Now we need to calculate two things. First, we get the code bank index that we are starting on. This
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; is easy, it's just the value of floor(Y / 16), but we pre-multiple by 4 for indexing into the table
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; of bank addresses. Next, we need to calculate the number of banks that the current range spans. This
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; will be either floor(ScreenHeight / 16) or floor(ScreenHeight / 16) + 1 depending on the exact value
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; of the Y position, so we actually calculate floor((ScreenHeight + Y % 16) / 16) and pre-multiple by 2.
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lsr ; divide by 4 (Y / 18 * 4 => Y / 4) and then truncate
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lsr ; the bottom two bits (and only keep relevant bits)
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and #$003C
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lsr ; divide by 4. This is really StartY / 16 but we
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lsr ; need to multiple by 4 to index into the array of
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and #$003C ; code bank addresses.
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tay
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; Quick stack save because we re-point the stack into some direct page space to aboid having to
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; mix 8 and 16 bit modes for bank anipulation
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tsc
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sta stksave
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lda StartY
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and #$000F
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sta start_mod_16 ; Save for later
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lda ScreenHeight
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sta lines_left
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lda StartY ; Now figure out exactly how many banks we cross by
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and #$000F ; calculating ((StartY % 16) + ScreenHeight) / 16
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sta start_mod_16
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clc
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adc ScreenHeight
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and #$00F0 ; Just keep the relevant nibble
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@ -189,16 +185,26 @@ SetYPos sta StartY ; Save the position
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lsr
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lsr
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tax ; Keep the value pre-multiplied by 2
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lsr
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sta bank_count ; This is the total number of action calls to make
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ldy #0
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jsr PushBanks ; Push the bank bytes on the stack
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brl :out
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; Start of the main body of the function. First, see if there are any unaligned lines to
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; handle in the first code bank.
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; Start of the main body of the function. We need to get a pointer to the correct offset of
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; the RTable to copy screen addresses into the code fields
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lda start_mod_16
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beq skip_pre
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lda ScreenY0
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asl
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clc
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adc #RTable
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sta tblptr
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; Check to see where we start. If we are aligned with a code bank, then skip to the
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; fast inner loop. Otherwise to one iteration to get things lined up
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:prologue lda start_mod_16
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beq :body
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_Mul4096 ; Save the offset into the code bank of the
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tay ; first line.
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@ -209,60 +215,62 @@ SetYPos sta StartY ; Save the position
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cmp ScreenHeight ; the number of lines in the code bank, we need to clamp
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bcc :min_1 ; the maximum value
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lda ScreenHeight
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:min_1 asl ; multiply the count by two
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pha ; save it for a second
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:min_1 sta tmp4 ; save for updating the counters
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clc
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adc line_x2
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sta line_x2 ; advance the line counter
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tax
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ldal RTable-2,x ; Load the ending address for this block
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asl
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tax ; do this many lines
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lda tblptr ; starting at this address
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plx ; Pop the number of lines * 2 to fill
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plb ; Set the code field bank
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jsr SetScreenAddrs
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skip_pre ldy #0
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lda line_x2
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clc
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adc #32
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cmp
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jsr CopyFromArray2 ; Copy the right screen edge addresses
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lda lines_left
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sec
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plb ; Set the code field bank
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ldal RTable+30,x ; Load the highest address for this code field bank
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jsr SetScreenAddrsTop ; to bypass the need to set the X register
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sbc tmp4
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sta lines_left
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lda tblptr
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clc
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adc tmp4
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adc tmp4
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sta tblptr
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; While the number of lines left to render is 16 or greater, loop
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:body lda lines_left
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cmp #16
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bcc :epilogue
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ldy #0
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ldx tblptr
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:body0 plb ; Set the code field bank
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jsr CopyFromArray2Top ; to bypass the need to set the X register
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txa
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clc
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adc #32
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tax
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ldy #0
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jsr SetScreenAddrsTop ; bypass X-register
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lda lines_left
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sec
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sbc #16
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sta lines_left
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dec loop_count
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cmp #16 ; Repeat the test here to we can skip some
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bcs :body0 ; redundant setup and spill the X register
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stx tblptr ; back into tblptr when done
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lda line_count ; with some pre-calc, we can just decrement a
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sec ; counter because we know the remaining line
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sbc #16 ; count is line_count % 16
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sta line_count
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cmp #16
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bcs core_loop
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:epilogue lda lines_left
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beq :out
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lda line_count
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beq :no_post
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:no_post
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asl ; Y is still zero
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tax
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lda tblptr
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plb ; Set the code field bank
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; jsr (action)
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jsr CopyFromArray2 ; to bypass the need to set the X register
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:out phk ; Need to restore the current bank
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:out lda stksave ; put the stack back
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tcs
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phk ; Need to restore the current bank
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plb
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rts
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@ -276,39 +284,39 @@ skip_pre ldy #0
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Mod208 cmp #%1101000000000000
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bcc *+5
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sbc #$1101000000000000
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sbc #%1101000000000000
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cmp #%0110100000000000
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bcc *+5
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sbc #$0110100000000000
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sbc #%0110100000000000
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cmp #%0011010000000000
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bcc *+5
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sbc #$0011010000000000
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sbc #%0011010000000000
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cmp #%0001101000000000
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bcc *+5
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sbc #$0001101000000000
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sbc #%0001101000000000
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cmp #%0000110100000000
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bcc *+5
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sbc #$0000110100000000
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sbc #%0000110100000000
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cmp #%0000011010000000
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bcc *+5
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sbc #$0000011010000000
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sbc #%0000011010000000
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cmp #%0000001101000000
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bcc *+5
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sbc #$0000001101000000
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sbc #%0000001101000000
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cmp #%0000000110100000
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bcc *+5
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sbc #$0000000110100000
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sbc #%0000000110100000
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cmp #%0000000011010000
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bcc *+5
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sbc #$0000000011010000
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sbc #%0000000011010000
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rts
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; BankYSetup
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@ -370,57 +378,50 @@ SetNextLine lda #$F000+{entry_3-base}
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ldx #15*2
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jmp SetAbsAddrs
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; Push a series of bank bytes onto the stack that are use to iterate among the
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; different code banks.
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; Copy a series of bank bytes onto the direct page, which we will later point the stack
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; at, and are use to iterate among the different code banks.
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;
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; Y = starting index * 4
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; X = number of bank
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;
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; Bytes are pushed in reverse order, so popping the banks will set the B register
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; in acending order, as expected (top to bottom)
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;
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; This is a bit of an unusual routine, we switch to 8-bit index registers and 16-bit accumulator.
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; That way we can cache the return address in the accumulator and use the index registers for
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; moving the data. This is OK, because the arrays are small, so X and Y are much smaller than 256.
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PushBanks pla ; Pop off the return address
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sep #$10
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PushBanks sep #$20
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jmp (:tbl,x)
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:tbl da :bottom-04,:bottom-08,:bottom-12,:bottom-16
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da :bottom-20,:bottom-24,:bottom-28,:bottom-32
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da :bottom-36,:bottom-40,:bottom-44,:bottom-48
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da :bottom-52
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:top ldx: BlitBuff+48,y ; These are all 8-bit loads and pushes
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phx
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ldx: BlitBuff+44,y
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phx
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ldx: BlitBuff+42,y
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phx
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ldx: BlitBuff+38,y
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phx
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ldx: BlitBuff+34,y
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phx
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ldx: BlitBuff+30,y
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phx
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ldx: BlitBuff+26,y
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phx
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ldx: BlitBuff+22,y
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phx
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ldx: BlitBuff+18,y
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phx
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ldx: BlitBuff+14,y
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phx
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ldx: BlitBuff+10,y
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phx
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ldx: BlitBuff+6,y
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phx
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ldx: BlitBuff+2,y
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phx
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:bottom rep #$10
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pha ; Push the return address back to the top of the stack
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:top lda: BlitBuff+48,y ; These are all 8-bit loads and stores
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sta bstk+13
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lda: BlitBuff+44,y
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sta bstk+12
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lda: BlitBuff+42,y
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sta bstk+11
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lda: BlitBuff+38,y
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sta bstk+10
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lda: BlitBuff+34,y
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sta bstk+9
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lda: BlitBuff+30,y
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sta bstk+8
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lda: BlitBuff+26,y
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sta bstk+7
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lda: BlitBuff+22,y
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sta bstk+6
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lda: BlitBuff+18,y
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sta bstk+5
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lda: BlitBuff+14,y
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sta bstk+4
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lda: BlitBuff+10,y
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sta bstk+3
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lda: BlitBuff+6,y
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sta bstk+2
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lda: BlitBuff+2,y
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sta bstk+1
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lda: BlitBuff,y
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sta bstk
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:bottom rep #$20
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rts
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; Patch an 8-bit or 16-bit value into the bank. These are a set up unrolled loops to
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; Patch an 8-bit or 16-bit valueS into the bank. These are a set up unrolled loops to
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; quickly patch in a constanct value, or a value from an array into a given set of
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; templates.
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;
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@ -568,6 +569,59 @@ RestoreOpcode pha ; save the accumulator
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sta: $0000,y
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:bottom rts
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; CopyFromArray
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;
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; Copy values from an array with a stride of two bytes into the code field
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;
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; X = number of lines * 2, 0 to 32
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; Y = starting line * $1000
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; A = array address
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CopyFromArray2 pha ; save the accumulator
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ldal :tbl,x
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dec
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plx ; put the accumulator into X
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pha ; push the address into the stack
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rts ; and jump
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:tbl da bottomCFA2-00,bottomCFA2-06,bottomCFA2-12,bottomCFA2-18
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da bottomCFA2-24,bottomCFA2-30,bottomCFA2-36,bottomCFA2-42
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da bottomCFA2-48,bottomCFA2-54,bottomCFA2-60,bottomCFA2-66
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da bottomCFA2-72,bottomCFA2-78,bottomCFA2-84,bottomCFA2-90
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da bottomCFA2-96
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CopyFromArray2Top lda: $001E,x
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sta $F000,y
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lda: $001C,x
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sta $E000,y
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lda: $001A,x
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sta $D000,y
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lda: $0018,x
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sta $C000,y
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lda: $0016,x
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sta $B000,y
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lda: $0014,x
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sta $A000,y
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lda: $0012,x
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sta $9000,y
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lda: $0010,x
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sta $8000,y
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lda: $000E,x
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sta $7000,y
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lda: $000C,x
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sta $6000,y
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lda: $000A,x
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sta $5000,y
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||||
lda: $0008,x
|
||||
sta $4000,y
|
||||
lda: $0006,x
|
||||
sta $3000,y
|
||||
lda: $0004,x
|
||||
sta $2000,y
|
||||
lda: $0002,x
|
||||
sta $1000,y
|
||||
lda: $0000,x
|
||||
sta: $0000,y
|
||||
bottomCFA2 rts
|
||||
|
||||
; SetScreenAddrs
|
||||
;
|
||||
@ -578,13 +632,13 @@ RestoreOpcode pha ; save the accumulator
|
||||
; Automatically decrements address by 160 bytes each line
|
||||
SetScreenAddrs sec
|
||||
jmp (:tbl,x)
|
||||
:tbl da :bottom-00,:bottom-03,:bottom-09,:bottom-15
|
||||
da :bottom-21,:bottom-27,:bottom-33,:bottom-39
|
||||
da :bottom-45,:bottom-51,:bottom-57,:bottom-63
|
||||
da :bottom-69,:bottom-75,:bottom-81,:bottom-87
|
||||
da :bottom-93
|
||||
SetScreenAddrsTop
|
||||
:top sta STK_ADDR+$F000,y
|
||||
:tbl da bottomSSA-00,bottomSSA-03,bottomSSA-09,bottomSSA-15
|
||||
da bottomSSA-21,bottomSSA-27,bottomSSA-33,bottomSSA-39
|
||||
da bottomSSA-45,bottomSSA-51,bottomSSA-57,bottomSSA-63
|
||||
da bottomSSA-69,bottomSSA-75,bottomSSA-81,bottomSSA-87
|
||||
da bottomSSA-93
|
||||
|
||||
SetScreenAddrsTop sta STK_ADDR+$F000,y
|
||||
sbc #160
|
||||
sta STK_ADDR+$E000,y
|
||||
sbc #160
|
||||
@ -615,7 +669,7 @@ SetScreenAddrsTop
|
||||
sta STK_ADDR+$1000,y
|
||||
sbc #160
|
||||
sta: STK_ADDR+$0000,y
|
||||
:bottom rts
|
||||
bottomSSA rts
|
||||
|
||||
; SetAbsAddrs
|
||||
;
|
||||
@ -953,120 +1007,6 @@ top
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user