65 lines
1.2 KiB
Plaintext
65 lines
1.2 KiB
Plaintext
; This file is part of the snescom-asm demo - a demo of how to build a SNES program.
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; See http://bisqwit.iki.fi/source/snescom.html for details.
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#include "memmap.i65"
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#include "dma.i65"
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#define TILE_ADDR_REG_VAL(addr, scsize) \
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(((addr & $FC00) >> 8) + scsize)
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#define BMAP_ADDR_REG_VAL(addr, addr2) \
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(((addr & $F000) >> 12) | (((addr2 & $F000) >> 12) << 4))
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; NMI - called on VBlank
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NMI_ROUTINE:
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sep #$20 : .as
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lda #$00
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pha
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plb
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lda $4210
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ldx #BG1_TILE_BASE+32*10
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stx $2116
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DMA0(#$01, #$380*2-64*10, #^BG1_TILE_BUF, #!BG1_TILE_BUF+64*10, #$18)
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ldx #BG2_TILE_BASE+32*10
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stx $2116
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DMA0(#$01, #$380*2-64*10, #^BG2_TILE_BUF, #!BG2_TILE_BUF+64*10, #$18);
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ldx #BG2_TILE_BASE
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stx $2116
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DMA0(#$01, #64*10, #^BG2_TILE_BUF, #!BG2_TILE_BUF, #$18);
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lda bar_pos
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inc
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bne +
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inc
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+
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cmp #224
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bne +
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lda #1
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+
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sta bar_pos
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cmp #113
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bcs lower_half
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sta hdma_math
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lda #$01
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sta hdma_math+3
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bra math_cont
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lower_half
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clc
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sbc #111
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sta hdma_math+3
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lda #112
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sta hdma_math
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math_cont
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lda #$3e ; ch. 1-5
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sta @$420c ; trigger HDMA
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rtl
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; IRQ - called when triggered (which is..?)
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IRQ_ROUTINE:
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sep #$20 : .as
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lda $4211 ;Acknowledge irq
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rtl
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