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33 lines
857 B
ArmAsm
33 lines
857 B
ArmAsm
.export vdc_init
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.include "pce.inc"
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; FIXME: implement selection of different video modes at runtime
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HIRES = 1
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vdc_init:
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lda VDC_CTRL
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VREG VDC_CR , $0000 ; disable display and interrupts
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VREG VDC_BXR, $0000 ; no scrolling
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VREG VDC_BYR, $0000
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VREG VDC_MWR, $0070 ; 128 x 64 tiles (1024 x 512 pixels)
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VREG VDC_VSR, $1702 ; CRTC
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VREG VDC_VDR, $00DF ; CRTC - VDS
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VREG VDC_VCR, $000C ; CRTC - VDE
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VREG VDC_DCR, $0000
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.if HIRES
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VREG VDC_HSR, $0C02 ; CRTC
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VREG VDC_HDR, $043C ; CRTC - HDS
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lda #$06
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.else
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VREG VDC_HSR, $0202 ; CRTC
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VREG VDC_HDR, $041F ; CRTC - HDS
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lda #$04
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.endif
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sta VCE_CTRL
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lda VDC_CTRL
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rts
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