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Tided MODE fall-back 

MODEs sorted into logical order and optimised fall-back for unsupported MODEs.
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jgharston 2023-01-21 22:12:52 +00:00 committed by GitHub
parent 4174fe86ee
commit 7d58b3aa6a
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1 changed files with 26 additions and 17 deletions
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43
auxmem.vdu.s
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@ -112,16 +112,18 @@ VDUWORKSZ EQU VDUVAREND-VDUWORKSP+1
*
* Screen definitions
* 0 1 2 3 6 7 ; MODEs sort-of completed
* 0 1 3 4 6 7 ; MODEs sort-of completed
SCNTXTMAXX DB 79, 39, 39, 79, 39, 39, 39, 39 ; Max text column
SCNTXTMAXY DB 23, 23, 23, 23, 23, 23, 23, 23 ; Max text row
SCNBYTES DB 08, 08, 08, 01, 01, 01, 01, 01 ; Bytes per character
SCNCOLOURS DB 03, 15, 07, 01, 01, 01, 01, 01 ; Colours-1
SCNPIXELS DB 04, 02, 07, 00, 00, 00, 00, 00 ; Pixels per byte
SCNTYPE DB 65, 64,128, 01, 00, 00, 00, 32 ; Screen type
SCNBYTES DB 08, 08, 08, 01, 08, 01, 01, 01 ; Bytes per character
SCNCOLOURS DB 03, 15, 15, 01, 07, 01, 01, 01 ; Colours-1
SCNPIXELS DB 04, 02, 02, 00, 07, 00, 00, 00 ; Pixels per byte
SCNFALLBACK DB 03, 04, 05, 03, 04, 05, 06, 07 ; Fall back if unsupported
SCNTYPE DB 65, 64, 66, 01,128, 02, 00, 32 ; Screen type
* b7=FastDraw -> HGR mode
* b6=SHR mode on Apple IIgs
* b5=Teletext
* b1=40COL/20COL
* b0=40COL/80COL
* Colour table
@ -704,15 +706,16 @@ VDUINIT STA VDUQ+8
* MODEs available:
* MODE 0 - 640x200 SHR graphics, 80x24 bitmap text (GS only)
* MODE 1 - 320x200 SHR graphics, 40x24 bitmap text (GS only)
* MODE 2 - 280x192 HGR graphics, 40x24 bitmap text
* MODE 2 --> MODE 1
* MODE 3 - 80x24 text
* MODE 4 --> MODE 6
* MODE 4 - 280x192 HGR graphics, 40x24 bitmap text
* MODE 5 --> MODE 6
* MODE 6 - 40x24 text
* MODE 7 - 40x24 with $80-$9F converted to spaces
*
* On //e, MODE 0 -> MODE 3
* MODE 1 -> MODE 6
* MODE 1 -> MODE 4
* MODE 2 -> MODE 5
*
VDU22 JSR NEGCALL ; Find machine type
AND #$0F
@ -721,16 +724,22 @@ VDU22 JSR NEGCALL ; Find machine type
:NOTGS STA VDUBANK
LDA VDUQ+8
AND #$07
; jgh
BIT VDUBANK
BMI :INIT ; Skip if GS
CMP #$00 ; Mode 0?
BNE :S1
LDA #$03 ; --> Mode 3 instead
BRA :INIT
:S1 CMP #$01 ; Mode 1?
BNE :INIT
LDA #$06 ; --> Mode 6 instead
BMI :INIT ; All MODEs supported
CMP #$03
BCS :INIT
ADC #$03 ; Fall back to replacement MODE
; BIT VDUBANK
; BMI :INIT ; Skip if GS
; CMP #$00 ; Mode 0?
; BNE :S1
; LDA #$03 ; --> Mode 3 instead
; BRA :INIT
;:S1 CMP #$01 ; Mode 1?
; BNE :INIT
; LDA #$06 ; --> Mode 6 instead
:INIT TAX ; Set up MODE
STX VDUMODE ; Screen MODE