tb1/tb1_snes/opening.s
2013-01-22 16:23:11 -05:00

305 lines
6.3 KiB
ArmAsm

; Fade in
; Display the Opening VMW Logo
; eventually play music
; wait until button pressed
; Fade out
.segment "STARTUP"
display_opening:
rep #$10 ; X/Y = 16 bit
.i16
sep #$20 ; mem/A = 8 bit
.a8
;==========================
; Setup Backgrounds
;==========================
; we want the BG1 Tilemap to start at VRAM $F000 (60k)
; Format is
; aaaa aass a is shifted by 10 for address
; ss = size of screen in tiles 00 = 32x32
;
; 1111 0000
lda #$78 ; BG1 Tilemap starts at VRAM $F000
sta $2107 ; bg1 src
; we want the BG2 Tilemap to start at VRAM $F800
; Format is
; aaaa aass a is shifted by 10 for address
; ss = size of screen in tiles 00 = 32x32
;
; 1111 1000
lda #$7c ; BG2 Tilemap starts at VRAM $F800
sta $2108 ; bg2 src
; aaaa bbbb a= BG2 tiles, b= BG1 tiles
; bbbb<<13
; 0000 0000
; our BG1 tiles are stored starting in VRAM $0000
; our BG2 tiles are stored starting in VRAM $e000
lda #$70
sta $210b ; bg1 tile data starts at VRAM 0000
;==============
; Load Palettes
;==============
.a8
.i16
stz $2121 ; CGRAM color-generator read/write address
ldy #$00fe ; we have 127 colors / 512 bytes
ldx #$0000 ; pointer
opening_copypal:
lda f:vmw_logo_palette, x ; load byte of palette
sta $2122 ; store to color generator
inx
dey
bne opening_copypal
; make last color white
lda #$ff
sta $2122
lda #$7f
sta $2122
;=====================
; Load Tile Data
;=====================
; replace with DMA!
rep #$20 ; set accumulator/mem to 16bit
.a16
.i16
lda #$0020 ;
sta $2116 ; set adddress for VRAM read/write
; multiply by 2, so 0x0000
ldy #$2580 ; Copy 300 tiles, which are 64 bytes each
; 8x8 tile with 8bpp (four bits per pixel)
; in 2-byte chunks, so
; (300*64)/2 = 9600 = 0x2580
ldx #$0000
opening_copy_tile_data:
lda f:vmw_logo_tile_data, x
sta $2118 ; write the data
inx ; increment by 2 (16-bits)
inx
dey ; decrement counter
bne opening_copy_tile_data
;=====================
; Load TB_FONT Data
;=====================
; replace with DMA!
rep #$20 ; set accumulator/mem to 16bit
.a16
.i16
lda #$7000 ;
sta $2116 ; set adddress for VRAM read/write
; multiply by 2, so 0xe000
ldy #$0800 ; Copy 128 tiles, which are 32 bytes each
; 8x8 tile with 4bpp (four bits per pixel)
; in 2-byte chunks, so
; (128*32)/2 = 2048 = 0x0800
ldx #$0000
opening_copy_font_data:
lda f:tb_font, x
sta $2118 ; write the data
inx ; increment by 2 (16-bits)
inx
dey ; decrement counter
bne opening_copy_font_data
;===================================
; clear background to linear tilemap
;===================================
.a16
.i16
opening_clear_linear_tilemap:
; 6 down, 1 right = (6*32)+1 = 97 = 0xc1
; 1111 0000 1100 0001
lda #$78c1 ; we set tilemap to be at VRAM 0xf000 earlier
; f0c1
sta $2116
ldy #$0001 ; clear counters
; store to VRAM
; the bottom 8 bits is the tile to use
; the top 8 bits is vhopppcc
; vert flip, horiz flip o=priority
; p = palette, c=top bits of tile#
ldx #$0001
; 8-bit color so ppp is 0
; and we have a linear tilemap
; 0000 0000
; vhop ppcc cccc cccc
.a16
.i16
opening_fill_screen_loop:
cpx #31
bne opening_not_thirty
stz $2118
stz $2118
ldx #$0000
bra opening_check_end
opening_not_thirty:
tya
sta $2118
iny
opening_check_end:
inx
cpy #$0140 ; (10*32) = 0x140
bne opening_fill_screen_loop
; Write String to Background
opening_put_string:
; 1111 1101 0000 1000
lda #$7e44 ; set VRAM address
; f800 = upper left
; want 4x20, so (20 * 64) + 4*2 = 1288 = 0x508
; fd08
sta $2116 ; set VRAM r/w address
ldx #$0000 ; string index
; vhop ppcc cccc cccc
lda #$1c00 ; clear A
opening_copy_string:
sep #$20 ; set accumulator to 8 bit
; as we only want to do an 8-bit load
.a8
lda opening_string, x ; load string character
; while leaving top 8-bits alone
beq opening_done_copy_string
rep #$20 ; set accumulator back to 16 bit
.a16
sta $2118 ; store to VRAM
; the bottom 8 bits is the tile to use
; the top 8 bits is vhopppcc
; vert flip, horiz flip o=priority
; p = palette, c=top bits of tile#
inx ; increment string pointer
bra opening_copy_string
opening_done_copy_string:
opening_setup_video:
sep #$20 ; set accumulator to 8 bit
; as we only want to do an 8-bit load
.a8
.i16
; Enable sprite
; sssnnbbb
; ss = size (8x8 in our case)
; nn = name
; bb = base selection, VRAM >> 14
; lda #%00000010 ; point at 0x4000 in VRAM
; sta $2101
; 000abcde
; a = object, b=BG4 c=BG3 d=BG2 e=BG1
; lda #%00010001 ; Enable BG1
; lda #%00000011 ; Enable BG1
lda #%00000011 ; Enable BG1 & BG2
sta $212c
; disable subscreen
stz $212d
; abcd efff
; abcd = 8 (0) or 16 width for BG1234
; e = priority for BG3
; fff = background mode
lda #$03
sta $2105 ; set Mode 3
; a000 bbbb
; a = screen on/off (0=on), ffff = brightness
lda #$0f
sta $2100 ; Turn on screen, full Brightness
; lda #$81 ; Enable NMI (VBlank Interrupt) and joypads
lda #$01 ; enable joypad
sta $4200 ;
opening_joypad_read:
lda $4212 ; get joypad status
and #%00000001 ; if joy is not ready
bne opening_joypad_read ; wait
lda $4219 ; read joypad (BYSTudlr)
and #%11110000 ; see if a button pressed
beq opening_joypad_read
; if so, skip and don't move ball
lda #$80
sta $2100 ; Turn off screen
rts
opening_string:
.asciiz "A VMW SOFTWARE PRODUCTION"
.segment "HIGHROM"
tb_font:
.include "tbfont.inc"
.include "tb1_opening.tiles"