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Added bitshifting to VDU5 so can position in any column

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Bobbi Webber-Manners 2023-01-12 18:06:04 -05:00
parent df6970a52f
commit ffb61077bf
3 changed files with 75 additions and 4 deletions
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BIN
applecorn.po
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2
auxmem.init.s
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@ -224,5 +224,5 @@ BYTE00 BEQ BYTE00A ; OSBYTE 0,0 - generate error
RTS ; %000x1xxx host type, 'A'pple
BYTE00A BRK
DB $F7
HELLO ASC 'Applecorn MOS 2022-01-10'
HELLO ASC 'Applecorn MOS 2022-01-12'
DB $00 ; Unify MOS messages

77
mainmem.shr.s
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@ -215,7 +215,6 @@ SHRCHAR640 PHY ; Preserve Y
* VDU5 plot char at graphics cursor position
* TODO: Need to do bitshifting for x-position
SHRVDU5CH >>> ENTMAIN
PHP ; Disable interrupts
SEI
@ -290,9 +289,23 @@ SHRVDU5CH >>> ENTMAIN
LSR A2L ; Divide by 2 again
:M1 LDX A1L ; Index into exploded font
STZ :ROWCTR
:L0 LDY A2L ; Index into row of pixels
:L0
PHX
LDY #$00
:LOOP LDAL $E10000,X ; Read a word of exploded font
STA :PIXBUF,Y ; Store word to shift buffer
INX
INX
INY
INY
CPY :BYTES
BNE :LOOP
LDA SHRXPIXEL
JSR SHRSHIFT ; Shift :PIXBUF to the right
LDY A2L ; Index into row of pixels
STZ :COLCTR
:L1 LDAL $E10000,X ; Read byte of exploded font
LDX #$00
:L1 LDA :PIXBUF,X ; Read word of exploded font
PHX
SEP #$30 ; 8 bit M & X
MX %11 ; Tell Merlin
@ -306,6 +319,12 @@ SHRVDU5CH >>> ENTMAIN
LDA :COLCTR
CMP :BYTES ; Bytes per row
BNE :L1
PLA ; Restore saved X -> A
CLC ; Add bytes per row
ADC :BYTES
TAX ; Back to X
LDA A3L ; Increment A3L/H to next row
CLC
ADC #$A0
@ -326,8 +345,60 @@ SHRVDU5CH >>> ENTMAIN
:COLCTR EQU TMPZP+0
:ROWCTR EQU TMPZP+2
:BYTES EQU TMPZP+4 ; Bytes per char row
:PIXBUF EQU TMPZP+6 ; Shift buffer (6 bytes)
* Shifts one character row of pixels to the right
* Called in 65816 native mode, 16 bit M & X
* On entry: A - x-coordinate of char
SHRSHIFT MX %00 ; Tell merlin we are 16 bit M&X
PHA
LDA SHRPIXELS ; Pixels per byte
AND #$00FF
CMP #$02 ; 2 is 320-mode (MODE 1)
BNE :MODE0
PLA
AND #$0001 ; Bits to shift in MODE 1
ASL
PHA
:MODE0 PLA
AND #$0003 ; Bits to shift in MODE 0
PHA
LDA :PIXBUF ; Put bytes in big-endian order
XBA
STA :PIXBUF
LDA :PIXBUF+2
XBA
STA :PIXBUF+2
LDA :PIXBUF+4
XBA
STA :PIXBUF+4
PLA
:L1 CMP #$0000
BEQ :S1
LSR :PIXBUF ; Shift :PIXBUF to the right 1 bit
ROR :PIXBUF+2
ROR :PIXBUF+4
LSR :PIXBUF ; Shift right again
ROR :PIXBUF+2
ROR :PIXBUF+4
DEC A
BRA :L1
:S1 LDA :PIXBUF ; Put bytes back in little-endian
XBA
STA :PIXBUF
LDA :PIXBUF+2
XBA
STA :PIXBUF+2
LDA :PIXBUF+4
XBA
STA :PIXBUF+4
RTS
MX %11
* Handle cursor left in VDU5 mode
SHRVDU08 >>> ENTMAIN
PHP ; Disable interrupts