277 lines
9.3 KiB
ArmAsm
277 lines
9.3 KiB
ArmAsm
* AUXMEM.SHR.S
|
|
* (c) Bobbi 2022 GPLv3
|
|
*
|
|
* Routines for drawing bitmapped text and graphics in SHR mode
|
|
* on Apple IIGS (640x200 4 colour, or 320x200 16 colour.)
|
|
*
|
|
|
|
SCB320 EQU $00 ; SCB for 320 mode
|
|
SCB640 EQU $80 ; SCB for 640 mode
|
|
|
|
|
|
* Colours in the following order.
|
|
* For 16 colour modes ...
|
|
* BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE, ...
|
|
* For 4 colour modes ...
|
|
* BLACK, RED, YELLOW, WHITE
|
|
|
|
PALETTE320 DB $00, $00 ; BLACK
|
|
DB $00, $08 ; RED
|
|
DB $80, $00 ; GREEN
|
|
DB $80, $08 ; YELLOW
|
|
DB $08, $00 ; BLUE
|
|
DB $08, $08 ; MAGENTA
|
|
DB $88, $00 ; CYAN
|
|
DB $88, $08 ; WHITE
|
|
DB $00, $00 ; BLACK
|
|
DB $00, $08 ; RED
|
|
DB $80, $00 ; GREEN
|
|
DB $80, $08 ; YELLOW
|
|
DB $08, $00 ; BLUE
|
|
DB $08, $08 ; MAGENTA
|
|
DB $88, $00 ; CYAN
|
|
DB $88, $08 ; WHITE
|
|
|
|
PALETTE640 DB $00, $00 ; BLACK
|
|
DB $00, $08 ; RED
|
|
DB $80, $08 ; YELLOW
|
|
DB $88, $08 ; WHITE
|
|
DB $00, $00 ; BLACK
|
|
DB $00, $08 ; RED
|
|
DB $80, $08 ; YELLOW
|
|
DB $88, $08 ; WHITE
|
|
DB $00, $00 ; BLACK
|
|
DB $00, $08 ; RED
|
|
DB $80, $08 ; YELLOW
|
|
DB $88, $08 ; WHITE
|
|
DB $00, $00 ; BLACK
|
|
DB $00, $08 ; RED
|
|
DB $80, $08 ; YELLOW
|
|
DB $88, $08 ; WHITE
|
|
|
|
SHRCOLMASK DB $00 ; Colour mask
|
|
|
|
|
|
* Enable SHR mode
|
|
SHRVDU22 JSR VDU12 ; Clear text and SHR screen
|
|
LDA #$80 ; Most significant bit
|
|
TSB NEWVIDEO ; Enable SHR mode
|
|
LDA VDUPIXELS ; Pixels per byte
|
|
CMP #$02 ; 2 is 320-mode (MODE 1)
|
|
BNE :MODE0
|
|
LDA #SCB320 ; SCB for 320-mode
|
|
LDY #00 ; Palette offset
|
|
BRA :S1
|
|
:MODE0 LDA #SCB640 ; SCB for 640-mode
|
|
LDY #32 ; Palette offset
|
|
:S1 LDX #$00
|
|
:L1 STAL $E19D00,X ; SCBs begin at $9D00 in $E1
|
|
INX
|
|
CPX #200 ; 200 lines so 200 SCBs
|
|
BNE :L1
|
|
LDX #$00
|
|
:L2 LDA PALETTE320,Y ; Offset in Y computed above
|
|
STAL $E19E00,X ; Palettes begin at $9E00 in $E1
|
|
INX
|
|
INY
|
|
CPX #32 ; 32 bytes in palette
|
|
BNE :L2
|
|
RTS
|
|
|
|
|
|
* Write character to SHR screen
|
|
* On entry: A - character to write
|
|
SHRPRCHAR SEC
|
|
SBC #32
|
|
STA ZP1+0 ; A*8 -> ZP1
|
|
STZ ZP1+1
|
|
ASL ZP1+0
|
|
ROL ZP1+1
|
|
ASL ZP1+0
|
|
ROL ZP1+1
|
|
ASL ZP1+0
|
|
ROL ZP1+1
|
|
CLC ; FONT8+A*8 -> ZP1
|
|
LDA ZP1+0
|
|
ADC #<FONT8
|
|
STA ZP1+0
|
|
LDA ZP1+1
|
|
ADC #>FONT8
|
|
STA ZP1+1
|
|
JSR SHRCHARADDR ; Addr in VDUADDR
|
|
LDY #$00 ; First row of char
|
|
:L1 >>> RDMAIN
|
|
LDA (ZP1),Y ; Load row of font
|
|
>>> RDAUX
|
|
LDX VDUPIXELS ; Pixels per byte
|
|
CPX #$02 ; 2 is 320-mode (MODE 1)
|
|
BNE :S1
|
|
JSR SHRCHAR320
|
|
BRA :S2
|
|
:S1 JSR SHRCHAR640
|
|
:S2 JSR SHRNEXTROW ; Add 160 to VDUADDR
|
|
INY ; Next row of font
|
|
CPY #$08 ; Last row?
|
|
BNE :L1
|
|
RTS
|
|
|
|
|
|
* Draw one pixel row of font in 320 mode
|
|
* 4 bytes per char, 4 bits per pixel
|
|
SHRCHAR320 PHY
|
|
LDA #$FF
|
|
LDY #$00
|
|
STA [VDUADDR],Y
|
|
INY
|
|
STA [VDUADDR],Y
|
|
INY
|
|
STA [VDUADDR],Y
|
|
INY
|
|
STA [VDUADDR],Y
|
|
PLY
|
|
RTS
|
|
|
|
|
|
* Draw one pixel row of font in 640 mode
|
|
* 2 bytes per char, 2 bits per pixel
|
|
SHRCHAR640 PHY
|
|
STZ :TEMP
|
|
LDX #$00 ; Source bit index
|
|
:L1 ASL ; MS bit -> C
|
|
PHP ; Preserve C
|
|
ROL :TEMP ; C -> LS bit
|
|
PLP ; Recover C
|
|
ROL :TEMP ; C -> LS bit
|
|
INX
|
|
CPX #$04
|
|
BNE :L1
|
|
PHA
|
|
LDA :TEMP
|
|
AND SHRCOLMASK ; Mask to set colour
|
|
STA [VDUADDR]
|
|
PLA
|
|
STZ :TEMP
|
|
LDX #$00
|
|
:L2 ASL ; MS bit -> C
|
|
PHP ; Preserve C
|
|
ROL :TEMP ; C -> LS bit
|
|
PLP ; Recover C
|
|
ROL :TEMP ; C -> LS bit
|
|
INX
|
|
CPX #$04
|
|
BNE :L2
|
|
LDA :TEMP
|
|
LDY #$01
|
|
AND SHRCOLMASK ; Mask to set colour
|
|
STA [VDUADDR],Y
|
|
PLY
|
|
RTS
|
|
:TEMP DB $00
|
|
|
|
|
|
* Calculate character address in SHR screen memory
|
|
* This is the address of the first pixel row of the char
|
|
* Add $00A0 for each subsequent row
|
|
SHRCHARADDR LDA #$20 ; MSB starts at $20
|
|
LDY VDUTEXTY
|
|
:L1 CPY #$00
|
|
BEQ :S1
|
|
CLC
|
|
ADC #05 ; Each char row is $500
|
|
DEY
|
|
BRA :L1
|
|
:S1 STA VDUADDR+1 ; MSB of address
|
|
LDA VDUTEXTX
|
|
ASL ; Mult x 2 (4 pixels/byte)
|
|
LDY VDUPIXELS ; Pixels per byte
|
|
CPY #$02 ; 2 pixels per byte in 320 mode
|
|
BNE :S2
|
|
ASL ; Mult x 2 (2 pixels/byte)
|
|
:S2 STA VDUADDR+0 ; LSB of address
|
|
LDA #$E1 ; Bank $E1
|
|
STA VDUBANK
|
|
RTS
|
|
* (VDUADDR)=>character address, X=preserved
|
|
|
|
|
|
* Advance VDUADDR to the next row of pixels
|
|
SHRNEXTROW LDA VDUADDR+0 ; Add 160 to VDUADDR
|
|
CLC
|
|
ADC #160
|
|
STA VDUADDR+0
|
|
LDA VDUADDR+1
|
|
ADC #$00
|
|
STA VDUADDR+1
|
|
RTS
|
|
|
|
|
|
* Forwards scroll one line
|
|
SHRSCR1LINE
|
|
RTS
|
|
|
|
|
|
* Reverse scroll one line
|
|
SHRRSCR1LINE
|
|
RTS
|
|
|
|
|
|
* Clear from current location to EOL
|
|
* TODO: This is only for 640 mode at present
|
|
SHRCLREOL JSR SHRCHARADDR
|
|
STZ VDUADDR+0 ; Addr of start of line
|
|
LDA #$08 ; Eight rows
|
|
STA :CTR
|
|
:L0 LDA VDUTEXTX
|
|
TAX
|
|
ASL ; 2 bytes / char
|
|
TAY
|
|
LDA #$00
|
|
:L1 CPX TXTWINRGT
|
|
BCS :S1
|
|
STA [VDUADDR],Y
|
|
INY
|
|
STA [VDUADDR],Y
|
|
INY
|
|
INX
|
|
BRA :L1
|
|
:S1 JSR SHRNEXTROW
|
|
DEC :CTR
|
|
BNE :L0
|
|
RTS
|
|
:CTR DB $00
|
|
|
|
|
|
* VDU16 (CLG) clears the whole SHR screen right now
|
|
SHRCLEAR PHP ; Disable interrupts
|
|
SEI
|
|
CLC ; 816 native mode
|
|
XCE
|
|
REP #$10 ; 16 bit index
|
|
MX %10 ; Tell Merlin
|
|
LDX #$0000
|
|
LDA #$00
|
|
:L1 STAL $E12000,X ; SHR screen @ E1:2000
|
|
INX
|
|
CPX #$7D00
|
|
BNE :L1
|
|
SEP #$10 ; Back to 8 bit index
|
|
MX %11 ; Tell Merlin
|
|
SEC ; Back to 6502 emu mode
|
|
XCE
|
|
PLP ; Normal service resumed
|
|
RTS
|
|
|
|
|
|
* Set text colour
|
|
* A=txt colour
|
|
SHRSETTCOL TAX
|
|
LDA :MASKS640,X ; Lookup mask in table
|
|
STA SHRCOLMASK ; Set colour mask
|
|
RTS
|
|
:MASKS640 DB %00000000
|
|
DB %01010101
|
|
DB %10101010
|
|
DB %11111111
|
|
|
|
|