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Work-in-progress VDU5 support in MODE 1

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Bobbi Webber-Manners 2023-01-08 08:06:13 -05:00
parent 23a6464ab9
commit d8067ff725
2 changed files with 91 additions and 4 deletions
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applecorn.po
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95
mainmem.shr.s
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@ -216,8 +216,96 @@ SHRCHAR640 PHY ; Preserve Y
* VDU5 plot char at graphics cursor position
SHRVDU5CH320 >>> ENTMAIN
* TODO
PHA ; Save char for later
LDX SHRYPIXEL ; Screen row (Y-coord)
LDA SHRROWSL,X ; Look up addr (LS byte)
STA A3L ; Stash in A3L
LDA SHRROWSH,X ; Look up addr (MS byte)
STA A3H ; Stash in A3H
LDA #$E1 ; Bank $E1
STA A4L
PLA ; Get char back
PHP ; Disable interrupts
SEI
CLC ; 65816 native mode
XCE
REP #$30 ; 16 bit M & X
MX %00 ; Tell Merlin
AND #$00FF
STA A1L ; A*32 -> A1L/H
ASL A1L
ASL A1L
ASL A1L
ASL A1L
ASL A1L
CLC ; SHRFONTXPLD+A*32 -> A1L/H
LDA A1L
ADC #SHRFONTXPLD
STA A1L
LDX SHRXPIXEL ; Screen col (X-coord)
STX A2L
LSR A2L ; Divide by 4
LSR A2L
LDX A1L ; Index into exploded font
STZ :CTR2
:L0 LDY A2L ; Index into row of pixels
STZ :CTR1
:L1 LDAL $E10000,X ; Read byte of exploded font
PHX
SEP #$30 ; 8 bit M & X
MX %11 ; Tell Merlin
JSR SHRPLOTBYTE
REP #$30 ; 16 bit M & X
MX %00 ; Tell Merlin
PLX
INX ; Next byte of font
INY ; Next byte on screen
INC :CTR1
LDA :CTR1
CMP #$04 ; 4 bytes per row
BNE :L1
LDA A3L ; Increment A3L/H to next row
CLC
ADC #$A0
STA A3L
LDA A3H
ADC #$00
STA A3H
INC :CTR2
LDA :CTR2
CMP #$08 ; 8 rows
BNE :L0
REP #$30 ; 16 bit M & X
MX %00 ; Tell Merlin
LDA SHRXPIXEL
CLC
ADC #$08
CMP #639-16
BCS :NEWLINE ; X-pos >= limit
STA SHRXPIXEL
BRA :DONE
:NEWLINE STZ SHRXPIXEL
LDA SHRYPIXEL
CMP #16
BCC :NEWPAGE ; Less than 16 rows left
SEC
SBC #$08
STA SHRYPIXEL
BRA :DONE
:NEWPAGE LDA #199
STA SHRYPIXEL
:DONE SEC ; 65816 emulation mode
XCE
PLP
>>> XF2AUX,SHRPRCH320RET
* Zero page
:CTR1 EQU TMPZP+0
:CTR2 EQU TMPZP+2
* VDU5 plot char at graphics cursor position
@ -325,7 +413,6 @@ SHRPOINT REP #$30 ; 16 bit M & X
BMI :OUT
CMP SHRWINTOP
BEQ :S1
BPL :OUT
:S1 LDA A1L ; x coordinate
CMP SHRWINLFT
BMI :OUT
@ -363,15 +450,15 @@ SHRPOINT2 SEP #$30 ; 8 bit M & X
TAX ; Index into :BITS320
LDA :BITS320,X ; Get bit pattern for pixel to set
BRA :DOPLOT
BRA SHRPLOTBYTE
:MODE0 TXA
AND #$03 ; Keep LSB two bits only
TAX ; Index into :BITS640
LDA :BITS640,X ; Get bit pattern for pixel to set
:DOPLOT PHA
SHRPLOTBYTE PHA
LDA SHRGFXACTION ; GCOL action
AND #$0007 ; Avoid table overflows
ASL