203 lines
3.0 KiB
ArmAsm
203 lines
3.0 KiB
ArmAsm
; flames -- Apple II Hires
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flames:
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;==================================================
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; clear both graphics screens, set to display page1
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; lda #$20
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; sta HGR_PAGE
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;=============================================
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; setup (draw white line at bottom of screen)
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ldy #39
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lda #$f
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white_line_loop:
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sta $5DD0,Y
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dey
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bpl white_line_loop
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;====================
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;====================
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; main loop
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;====================
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;====================
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fire_loop:
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lda #$20
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sta DRAW_PAGE
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;====================
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; move fire
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;====================
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move_fire:
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ldx #159 ; start at bottom of screen
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burn_loop:
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;======================
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; input in BASL/BASH
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lda hposn_low,X
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sta BASL
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lda hposn_high,X
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clc
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adc DRAW_PAGE
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sta BASH
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;========================
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; output in GBASL:GBASH
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dex ; point to line above
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stx XSAVE
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lda hposn_low,X
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sta GBASL ; put the line address into input
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lda hposn_high,X
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clc
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adc DRAW_PAGE
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sta GBASH
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ldy #39 ; 39 columns across screen
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burn_inner:
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random_smc:
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lda $900 ; our "RANDOM" numbers
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; lda $E000 ; our "RANDOM" numbers
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bpl dont_invert_dex ; is top bit random enough?
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lda dex_smc
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eor #$20
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sta dex_smc
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dont_invert_dex:
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;burn_in_smc:
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lda (BASL),Y
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tax
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; ldx $4000,Y
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beq skip_if_zero
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dex_smc: ; DEX = $CA, NOP = $EA
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dex
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skip_if_zero:
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txa
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;burn_out_smc:
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; sta $4000,Y
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sta (GBASL),Y
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inc random_smc+1 ; update "RNG"
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bne no_oflo
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inc random_smc+2
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lda random_smc+2
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cmp #$0c
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bne no_oflo
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lda #$09 ; wrap to "ROM"
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sta random_smc+2
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no_oflo:
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dey
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bpl burn_inner
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ldx XSAVE ; finish early as top of screen empty
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cpx #120
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bne burn_loop
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;====================
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; copy to visible
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copy_to_page1:
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; X should already be 150 here
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; ldx #150 ; only on bottom of screen
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copy_loop:
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; txa
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; jsr HPOSN ; puts addr of line in A into GBASL:GBASH
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lda hposn_low,X ; output on page1
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sta BASL
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sta GBASL
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lda hposn_high,X
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sta BASH
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clc
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adc #$20
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sta GBASH
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stx XSAVE
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; lda GBASL
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; sta BASL
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; sta copy_inner_smc+1
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; lda GBASH
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; eor #$60 ; flip to page 1
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; sta BASH
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; sta copy_inner_smc+2
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ldy #39
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copy_inner:
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lda (GBASL),Y
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tax
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lda color_lookup,X
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; sec ; or ora $80?
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ror_smc:
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; ror ; ROR = $6A 0110 1010
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; NOP = $EA 1110 1010
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copy_inner_smc:
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sta (BASL),Y
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; lda ror_smc
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; eor $80
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; sta ror_smc
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dey
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bpl copy_inner
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ldx XSAVE
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inx
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cpx #160
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bne copy_loop
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;====================
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; loop forever
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check_flame_keypress:
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lda KEYPRESS
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bmi done_flames
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jmp fire_loop ; bra
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done_flames:
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bit KEYRESET
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rts
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;=====================
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color_lookup:
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.byte $00 ; 1 0 00 00 00 BBBB 0
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.byte $84 ; 1 0 00 01 00 BB0B 1
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.byte $90 ; 1 0 01 00 00 BOBB 2
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.byte $81 ; 1 0 00 00 01 BBBO 3
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.byte $91 ; 1 0 01 00 01 BOBO 4
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.byte $C4 ; 1 1 00 01 00 OBOB 5
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.byte $D1 ; 1 1 01 00 01 OOBO 6
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.byte $DA ; 1 1 01 01 01 OOOO 7
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.byte $F5 ; 1 1 11 01 01 OWOO 8
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.byte $DD ; 1 1 01 11 01 WOWO 9
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.byte $FE ; 1 1 11 01 11 OWOW 10
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.byte $DF ; 1 1 01 11 11 OOWW 11
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.byte $F5 ; 1 1 11 01 01 WWOO 12
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.byte $FD ; 1 1 11 11 01 WWWO 13
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.byte $DF ; 1 1 01 11 11 WOWW 14
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.byte $ff ; 1 1 11 11 11 WWWW 15
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