dos33fsprogs/xmas_2018/merry.s

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2018-12-12 20:38:30 +00:00
;=====================================
; XMAS2018 -- Merry Christmas Part
;=====================================
merry:
;===================
; init screen
;===================
; init vars
lda #15
sta XPOS
lda #38
sta YPOS
lda #0
sta FRAME
sta FRAMEH
;=============================
; Load graphic hgr
; lda #<merry_hgr
; sta LZ4_SRC
; lda #>merry_hgr
; sta LZ4_SRC+1
; lda #<(merry_hgr_end-8) ; skip checksum at end
; sta LZ4_END
; lda #>(merry_hgr_end-8) ; skip checksum at end
; sta LZ4_END+1
; lda #<$2000
; sta LZ4_DST
; lda #>$2000
; sta LZ4_DST+1
; jsr lz4_decode
2018-12-12 20:38:30 +00:00
;==============================
; setup graphics for vapor lock
;==============================
jsr vapor_lock ; 6
; vapor lock returns with us at beginning of hsync in line
; 114 (7410 cycles), so with 5070 lines to go
; so we have 5070 + 4550 = 9620 to kill
; FIXME: clear page0/page1 screens
; jsr gr_copy_to_current ; 6+ 9292
; now we have 322 left
; GR part
; bit HIRES ; 4
bit SET_GR ; 4
bit FULLGR ; 4
; 9620
; -8 mode set
; - 3 for jmp
;=======
; 9609
; Try X=239 Y=8 cycles=9609
ldy #8 ; 2
meloopA:ldx #239 ; 2
meloopB:dex ; 2
bne meloopB ; 2nt/3
dey ; 2
bne meloopA ; 2nt/3
jmp merry_begin_loop
.align $100
;================================================
; Merry Christmas Loop
;================================================
; each scan line 65 cycles
; 1 cycle each byte (40cycles) + 25 for horizontal
; Total of 12480 cycles to draw screen
; Vertical blank = 4550 cycles (70 scan lines)
; Total of 17030 cycles to get back to where was
merry_begin_loop:
merry_display_loop:
; (40*65)-4 = 2596
; 40 lines of LORES
bit LORES ; 4
; Try X=42 Y=12 cycles=2593 R3
lda $0 ; nop ; 3
ldy #12 ; 2
meloopC:ldx #42 ; 2
meloopD:dex ; 2
bne meloopD ; 2nt/3
dey ; 2
bne meloopC ; 2nt/3
; rest of screen is hires page0
; (152*65)-4 = 9876
bit HIRES ; 4
; Try X=13 Y=139 cycles=9870 R6
nop
nop
nop
ldy #139 ; 2
meloopE:ldx #13 ; 2
meloopF:dex ; 2
bne meloopF ; 2nt/3
dey ; 2
bne meloopE ; 2nt/3
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; do_nothing should be 4550
; -10 keypress
; ===========
; 4540
; jsr play_music ; 6+1032
; Try X=9 Y=89 cycles=4540
ldy #89 ; 2
meloop1:ldx #9 ; 2
meloop2:dex ; 2
bne meloop2 ; 2nt/3
dey ; 2
bne meloop1 ; 2nt/3
; no keypress = 10+(24) = 34
lda KEYPRESS ; 4
bpl me_no_keypress ; 3
; -1
jmp me_handle_keypress ; 3
me_no_keypress:
jmp merry_display_loop ; 3
me_handle_keypress:
bit KEYRESET ; clear keypress ; 4
rts ; 6