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6502_linux_logo
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; 6502 Linux Logo
; Michaelangel007
; https://github.com/Michaelangel007/6502_linux_logo
; Zero Page ROM vars
zCursorX = $24 ; CH
zCursorY = $25 ; CH
zHgrPtr = $26 ; GBASL = Dst
zTxtPtr = $28 ; BASL = Dst
zSaveX = $F9
zSaveY = $FA
zMask = $FB ; 16-bit but Acc has low
zSrcShift = $FC ; i mod 8
zDstShift = $FD ; i mod 7
zUnpackBits = $FE ; 16-bit unpack
; ROM
HOME = $FC58
IB_HGR = $D000 ; Integer BASIC ][ only
AS_HGR = $F3E2 ; Applesoft BASIC ][+ or newer
BASCALC = $FBC1 ; A=Row, Calculate BASL,BASH text address
;Bank Addr -- Addr Bank Read --- Write -------
; 2 $C080 == $C088 1 Read RAM Write protect
; 2 $C081 == $C089 1 Read ROM Write enabled
; 2 $C082 == $C08A 1 Read ROM Write protect
; 2 $C083 == $C08B 1 Read RAM Write enabled
RAMIN = $C080
ROMIN = $C081
MACHINEID1 = $FBB3
MACHINEID2 = $FBC0
MACHINEID3 = $FBBF ; //c version
; Config
UnpackAddr = $200 ; $28 bytes at Keyboard buffer
CONFIG_PROBE_CPUINFO = 1
CONFIG_PRINT_CPUINFO = 1
; ========================================================================
ORG $900
Main
jsr HOME
; ------------------------------------------------------------------------
DO CONFIG_PROBE_CPUINFO
DetectCPU
; Apple II Technical Note #7
; https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20II/Documentation/Misc%20%23007%20Apple%20II%20Family%20ID.pdf
;
; Machine $FBB3 $FBC0 $FBBE
; Apple ][ $38
; Apple ][+ $EA
; Apple /// $EA
; Apple //e $06 $EA
; Apple //e+ $06 $E0
; Apple //e Option Card $06 $E0
; Apple //c $06 $00 $FF
; Apple //c 3.5 $06 $00 $00
; Apple //c Org Mem XP $06 $00 $03
; Apple //c Rev Mem XP $06 $00 $04
; Apple //c+ $06 $00 $05
; Apple IIgs
detect_ram
lda MACHINEID1 ; FBB3: $38 = ][, $EA = ][+, $06 = //e //c IIgs
pha
cmp #$38 ;
bne apple_iiplus
apple_ii
pla
jsr IB_HGR ; HGR on ][, ends with BNE $D01B
beq apple_ii_normal
apple_iiplus
jsr AS_HGR ; ][ = $D000, Only on Apple ][+
pla
cmp #$EA ; apple ][+?
bne apple_iie ; if so keep going
lda #"+"
bne set_apple_ii
; if we get here we're a ii+ or iii in emulation mode
apple_ii_normal
lda #" " ; $A0
set_apple_ii
sta ModType ; erase last 'e' in 'Apple IIe'
sta CpuType ; '_6502'
lda #"6"
sta CpuType+1
lda #"5"
sta CpuType+2
detect_langcard
sta RAMIN ; Detect 16K RAM / Language Card
sta RAMIN ; Read RAM
lda $D000
eor #$FF
sta $D000
cmp $D000
bne apple_ii_48K
eor #$FF
sta $D000
RAM_64K
ldx #"6"
ldy #"4"
bne RAM_size
apple_ii_48K
ldx #"4"
ldy #"8"
RAM_size
lda #" "
sta RamSize ; erase '1' in '128'
stx RamSize+1
sty RamSize+2
bne done_detecting
; Detect //e //e+ //c
apple_iie
lda MACHINEID2 ; FBC0: $00 = //c, $EA = //e, E0 = //e+
beq apple_iic ; check for apple //c
cmp #$E0 ; if we're an Apple IIe (original)
bne RAM_64K ; then use 64K and finish
beq apple_iie_enhanced
apple_iic
lda #"c"
sta CpuType+1
lda MACHINEID3
cmp #$05 ; //c+
bne done_detecting
apple_iie_enhanced ; //c+
ldx #1 ; //e+
jsr ModelPlus ; ^
done_detecting
sta ROMIN ; Turn off Language Card
sta ROMIN ; if it was probed
FIN
; ------------------------------------------------------------------------
; Unpack 2 bits/color -> $28 bytes/scanline
;
; Unpack one line to $200
; Copy to 8 scanlines
Unpack
DO 1-CONFIG_PROBE_CPUINFO
jsr AS_HGR ; *** DEBUG ***
FIN
lda #8 ; $0428 (Text) + $1C00 => $2028 (HGR)
sta zCursorY ; Start Row=8
DrawRow
jsr GetDestAddr
lda #0
tay
tax ; DstOffset within page
sta zDstShift
lda PackedBits
sta zUnpackBits+0
NextSrcShift
lda #0
sta zSrcShift
lda PackedBits+1,Y
sta zUnpackBits+1
GetBit
jsr Unpack2Bits ; hhggffee C=? ddccbbaa
bcs UnpackDone
lsr zUnpackBits+1 ; 0hhggffe C=e ddccbbaa
ror zUnpackBits+0 ; 0hhggffe C=e eddccbba
lsr zUnpackBits+1 ; 00hhggff C=e eddccbba
ror zUnpackBits+0 ; 00hhggff c=e eeddccbb
inc zSrcShift ;
inc zSrcShift
CheckFetch
lda zSrcShift
cmp #8 ; have 8 input bits?
bne GetBit
iny ; src++
cpy PackedLen
bcc NextSrcShift ; C=0 -> STZ zSrcShift
UnpackDone
; ------------------------------------------------------------------------
DO CONFIG_PRINT_CPUINFO
ldx #0
PrintText
jsr BASCALC ;
ldy #0
CopyTextLine
lda TextLine,X
sta (zTxtPtr),Y
inx ; 3*40 = 120 chars max
iny
cpy #40
bne CopyTextLine
inc zCursorY
lda zCursorY
cmp #$17 ; Rows $14..$16 (inclusive)
bne PrintText
dec zCursorY
; End of String offse for Model
; IN: X = 0 II+
; ^
; 1 //e+
; ^
ModelPlus
lda #"+"
sta ModType,x
FIN
rts
; ------------------------------------------------------------------------
; Expand 1 pixel (2 bits) via
; Output 2 pixels (4 bits)
Unpack2Bits
; DoublePixel
stx zSaveX
lda zUnpackBits
and #3 ; A=000000ba
pha
asl ; A=00000ba0
asl ; A=0000ba00
sta zMask
pla
ora zMask ; A=0000baba
ldx #0
stx zMask
ldx zDstShift
beq NoShiftSherlock
MakeShiftMask
asl
rol zMask
dex
bne MakeShiftMask
NoShiftSherlock
cmp #$80 ; msb of byte0 set?
rol zMask ; shift in to lsb of byte1
ldx zDstShift ; x={0,1,2} + 4 < 7
cpx #3 ; all bits fit into dest byte?
ldx zSaveX
ora #$80
ora UnpackAddr,X ; do all bits that fit
sta UnpackAddr,X
bcc UpdateDestOffset
; Update partial next byte of dest
inx
stx zSaveX
cpx #$28 ; C = x < 28
lda zMask
ora #$80
ora UnpackAddr,X
sta UnpackAddr,X
; x = x + 4 - 7
; x = x - 3
ldx zDstShift
dex
dex
dex
bcc LineNotDone ; C = x < 28
; ------------------------------------------------------------------------
; Copy Buffer to HGR
sty zSaveY
ldx #7 ; Repeat each scanline 8 times
Draw8Rows
ldy #0
CopyScanLine
lda UnpackAddr,Y
sta (zHgrPtr),Y
iny
cpy #40
bne CopyScanLine
clc ; y = y+1
lda zHgrPtr+1 ; addr_y+1 = addr_y + $0400
adc #$04
sta zHgrPtr+1
dex
bpl Draw8Rows
ldy zSaveY
inc zCursorY
jsr GetDestAddr
lda zCursorY
cmp #$14 ; Y=$40 .. $A0, Rows $8..$13 (inclusive)
bcs OuputDone
ldx #0
stx zSaveX
beq LineNotDone ; Next Scan Line, start at dst bit 0
UpdateDestOffset
ldx zDstShift
inx
inx
inx
inx
LineNotDone
stx zDstShift
clc
ldx zSaveX
OuputDone
rts
; ------------------------------------------------------------------------
; Udpate the Text Address
; Update the HGR scanline Address
; Clear the Text buffer
GetDestAddr
lda zCursorY
jsr BASCALC
lda zTxtPtr+0 ; every 8 HGR scanline address
sta zHgrPtr+0 ; is exactly same as Text low byte
lda zTxtPtr+1
clc ; every 8 HGR scanline address
adc #$1c ; is Text Page $04 + $1C = HGR Page $20
sta zHgrPtr+1
lda #0
ldx #40-1
ClearBuffer
sta UnpackAddr,X
dex
bpl ClearBuffer
rts
; ------------------------------------------------------------------------
CpuType = * + 13 + 40
RamSize = * + 30 + 40
ModType = * + 24 + 40*2
; Uppercase in case of Apple II without lowercase support
; 1 2 3
TextLine ;0123456789012345678901234567890123456789
ASC " LINUX VERSION 2.6.22.6, COMPILED 2007 " ; Row $14
ASC " ONE 1.02MHZ 65C02 PROCESSOR, 128KB RAM " ; Row $15
ASC " APPLE IIe " ; Row $16
; ^ ^ ^
; ------------------------------------------------------------------------
;"__________________________________________________________@@@@@_______"
;"_________________________________________________________@@@@@@@______"
;"______________A__________________________________________@@_@_@@______"
;"@@@@@@_______AA@_________________________________________@BBBBB@______"
;"__@@__________@________________________________________@@__BBB__@@____"
;"__@@_______AAA__@@@_@@@@___@@@____@@@__@@@@@_@@@@@____@__________@@___"
;"__@@______A__A@__@@@____@@__@@_____@@____@@___@@_____@____________@@__"
;"__@@_____A___A@__@@_____@@__@@_____@@_____@@_@@______@____________@@@_"
;"__@@________AA@__@@_____@@__@@_____@@______@@@______BB@___________@@B_"
;"__@@_____@_AA@___@@_____@@__@@_____@@_____@@_@@____BBBBB@_______@BBBBB"
;"__@@____@@_AA@_@_@@_____@@__@@@___@@@____@@___@@___BBBBBB@_____@BBBBBB"
;"@@@@@@@@@@__@@@_@@@@___@@@@___@@@@_@@@_@@@@@_@@@@@__BBBBB@@@@@@@BBBBB_"
; Char &3 Color
; @ 00 Black
; A 01 Blue
; B 10 Orange
; _ 11 White
; NOTE: Generated by ascii2hgr2bit
; ASCII: 70*12 = 840 chars
; Packed 2bits/2pixel: 70 chars * 2 bits/char / 8 bits/byte = 140 bits / 8 = 17.5 bytes
; 840 chars * 2 bits/color / 8 bits/byte = 210 bytes
PUT packedlogo.s
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