debugging disk operation

a2/disasm.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/gonuts/commander"
+	"github.com/zellyn/go6502/asm"
+)
+
+var cmdDisasm = &commander.Command{
+	Run:       runDisasm,
+	UsageLine: "disasm [-a address] filename",
+	Short:     "disassemble binary files",
+	Long: `
+Disasm is a very simple disassembler for 6502 binary files.
+`,
+}
+
+var disasmAddress uint // disasm -a flag
+
+func init() {
+	cmdDisasm.Flag.UintVar(&disasmAddress, "a", 0, "The starting memory address.")
+}
+
+func runDisasm(cmd *commander.Command, args []string) {
+	if len(args) != 1 {
+		cmd.Usage()
+		return
+	}
+
+	bytes, err := ioutil.ReadFile(args[0])
+	if err != nil {
+		log.Fatal(err)
+	}
+	if len(bytes) > 0x10000 {
+		log.Fatalf("File %s is %04X bytes long, which is more than $10000.", args[0], len(bytes))
+	}
+	if int(disasmAddress)+len(bytes) > 0x10000 {
+		log.Fatalf("Starting address ($%04X) + file length ($%04X) = $%X, which is > $10000",
+			disasmAddress, len(bytes), int(disasmAddress)+len(bytes))
+	}
+
+	asm.DisasmBlock(bytes, uint16(disasmAddress), os.Stdout)
+}

a2/main.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"log"
+	"os"
+
+	"github.com/gonuts/commander"
+	"github.com/gonuts/flag"
+)
+
+var a2cmd *commander.Commander
+
+func init() {
+	a2cmd = &commander.Commander{
+		Name: os.Args[0],
+		Commands: []*commander.Command{
+			cmdDisasm,
+		},
+		Flag: flag.NewFlagSet("a2", flag.ExitOnError),
+	}
+}
+
+func main() {
+	if err := a2cmd.Flag.Parse(os.Args[1:]); err != nil {
+		log.Fatal(err)
+	}
+	args := a2cmd.Flag.Args()
+	if err := a2cmd.Run(args); err != nil {
+		log.Fatal(err)
+	}
+}

cards/cards.go

@@ -10,6 +10,8 @@ type Card interface {
 	Write256(address byte, value byte) // Write to the $C(slot)XX addresses
 	Read(address uint16) byte          // Read from any address ($C800-$FFFF)
 	Write(address uint16, value byte)  // Write to any address ($C800-$FFFF)
+	WantTicker() bool
+	Tick()
 }
 
 type CardManager interface {

cards/disk.go

@@ -8,6 +8,7 @@ import (
 
 type Disk interface {
 	Read() byte
+	Skip(int)
 	Write(byte)
 	SetHalfTrack(byte)
 	HalfTrack() byte
@@ -16,14 +17,25 @@ type Disk interface {
 	Writeable() bool
 }
 
+const (
+	MODE_READ  = 0
+	MODE_WRITE = 1
+	MODE_SHIFT = 0
+	MODE_LOAD  = 2
+)
+
 type DiskCard struct {
-	rom     [256]byte
+	rom          [256]byte
-	cm      CardManager
+	cm           CardManager
-	slot    byte
+	slot         byte
-	slotbit byte
+	slotbit      byte
-	disks   [2]Disk
+	disks        [2]Disk
-	active  int
+	active       int
-	phases  byte
+	phases       byte
+	mode         byte
+	onOff        bool
+	dataRegister byte
+	lastAccess   int
 }
 
 func NewDiskCard(rom []byte, slot byte, cm CardManager) (*DiskCard, error) {
@@ -53,6 +65,9 @@ func (dc *DiskCard) ROMDisabled() {
 }
 
 func (dc *DiskCard) handlePhase(phase byte, onOff bool) {
+	if !dc.onOff {
+		return
+	}
 	phaseBit := byte(1 << phase)
 	if onOff {
 		dc.phases |= phaseBit
@@ -98,15 +113,90 @@ func (dc *DiskCard) handleAccess(address byte) {
 		dc.handlePhase(phase, onOff)
 		return
 	}
+	switch address {
+	case 0x8:
+		dc.onOff = false
+	case 0x9:
+		dc.onOff = true
+	case 0xA, 0xB:
+		which := int(address & 1)
+		if dc.active != which {
+			dc.active = which
+			dc.handlePhase(0, dc.phases&1 == 1) // No change: force update
+		}
+	case 0xC, 0xD:
+		dc.mode = dc.mode&^2 | address&1<<2
+	case 0xE, 0xF:
+		dc.mode = dc.mode&^1 | address&1
+	}
 }
 
 func (dc *DiskCard) Read16(address byte) byte {
 	dc.handleAccess(address)
-	return dc.cm.EmptyRead()
+	if address != 0xC && address != 0xE {
+		return 0xFF
+	}
+	if dc.onOff {
+		switch dc.mode {
+		case MODE_READ | MODE_SHIFT:
+			// Normal read
+			return dc.readOne()
+		case MODE_READ | MODE_LOAD:
+			// Check write-protect
+			if dc.disks[dc.active].Writeable() {
+				return 0x00
+			} else {
+				return 0xFF
+			}
+		case MODE_WRITE | MODE_SHIFT:
+			// Doesn't do anything in our simulation: just return last data
+			return dc.dataRegister
+		case MODE_WRITE | MODE_LOAD:
+			// Nonsense for reading: just return last data
+			return dc.dataRegister
+		}
+	}
+	return 0xFF
 }
 
 func (dc *DiskCard) Write16(address byte, value byte) {
 	dc.handleAccess(address)
+	if dc.onOff {
+		switch dc.mode {
+		case MODE_READ | MODE_SHIFT:
+			// Normal read
+			panic("Write while in read mode")
+		case MODE_READ | MODE_LOAD:
+			// Check write-protect
+			panic("Write while in check-write-protect mode")
+		case MODE_WRITE | MODE_SHIFT:
+			// Shifting data to disk
+			panic("Write while in shift mode")
+		case MODE_WRITE | MODE_LOAD:
+			if dc.disks[dc.active].Writeable() {
+				dc.writeOne(value)
+			}
+		}
+	}
+}
+
+func (dc *DiskCard) readOne() byte {
+	if dc.lastAccess < 4 {
+		return dc.dataRegister
+	}
+	disk := dc.disks[dc.active]
+	if dc.lastAccess > 300 {
+		disk.Skip(dc.lastAccess / 36)
+	}
+	dc.lastAccess = 0
+	dc.dataRegister = disk.Read()
+	return dc.dataRegister
+}
+
+func (dc *DiskCard) writeOne(value byte) {
+	disk := dc.disks[dc.active]
+	dc.dataRegister = value
+	disk.Write(value)
 }
 
 func (dc *DiskCard) Read(address uint16) byte {
@@ -128,3 +218,11 @@ func (dc *DiskCard) Write256(address byte, value byte) {
 func (dc *DiskCard) LoadDisk(d Disk, which int) {
 	dc.disks[which] = d
 }
+
+func (dc *DiskCard) WantTicker() bool {
+	return true
+}
+
+func (dc *DiskCard) Tick() {
+	dc.lastAccess++
+}

cards/firmware.go

@@ -70,3 +70,11 @@ func (fc *FirmwareCard) Read256(address byte) byte {
 func (fc *FirmwareCard) Write256(address byte, value byte) {
 	// Firmware is ROM: do nothing
 }
+
+func (fc *FirmwareCard) WantTicker() bool {
+	return false
+}
+
+func (fc *FirmwareCard) Tick() {
+	// do nothing
+}

disk/convert.go

@@ -96,12 +96,13 @@ func appendSyncs(target []byte, count int) []byte {
 
 // append44 appends bytes using the 4-4 encoded format used for volume, track, sector, checksum.
 func append44(target []byte, b byte) []byte {
-	return append(target, 0xAA|b<<1, 0xAA|b)
+	return append(target, 0xAA|(b>>1), 0xAA|b)
 }
 
 // appendAddress appends the encoded sector address to the slice, and returns the resulting slice.
 func appendAddress(target []byte, t, s, v byte) []byte {
 	target = append(target, 0xD5, 0xAA, 0x96)
+	fmt.Println("s=", s)
 	target = append44(target, v)
 	target = append44(target, t)
 	target = append44(target, s)

disk/dummy.go

@@ -3,7 +3,11 @@ package disk
 type Dummy byte
 
 func (v Dummy) Read() byte {
-	return 0xFF
+	return 0x00
+}
+
+func (v Dummy) Skip(int) {
+	// pass
 }
 
 func (v Dummy) Write(b byte) {

disk/nybble.go

@@ -55,6 +55,11 @@ func (disk *Nybble) Read() byte {
 	return track[disk.position]
 }
 
+func (disk *Nybble) Skip(amount int) {
+	track := disk.Tracks[disk.halfTrack/2]
+	disk.position = (disk.position + amount) % len(track)
+}
+
 func (disk *Nybble) Write(b byte) {
 	track := disk.Tracks[disk.halfTrack/2]
 	disk.position = (disk.position + 1) % len(track)

docs/apple2.org

@@ -155,6 +155,59 @@ Apple II notes
 | $F3     |     243 | FLASH MASK                                                     |
 | $F9     |     249 | ROT                                                            |
 
+* Page 00 DOS
+[BAD 8-42]
+
+|---------+-----+-----------------------------------------------|
+| Address | Dec | Description                                   |
+|---------+-----+-----------------------------------------------|
+| 24      |     | Cursor horizontal                             |
+| 26,27   |     | Sector read buffer address (ROM)              |
+| 28,29   |     | BASL/BASH (DOS)                               |
+| 2A      |     | Segment merge counter (ROM,BOOT)              |
+|         |     | Scratch space (RWTS)                          |
+| 2B      |     | BOOT slot*16 (ROM)                            |
+|         |     | Scratch space (RWTS)                          |
+| 2C      |     | Checksum from sector header (RWTS)            |
+| 2D      |     | Sector number form sector header (RWTS)       |
+| 2E      |     | Track number form sector header (RWTS)        |
+| 2F      |     | Volume number form sector header (RWTS)       |
+| 33      |     | Prompt character (DOS)                        |
+| 35      |     | Drive number in high bit (RWTS)               |
+| 36,37   |     | CSWL,CSWH (DOS)                               |
+| 38,39   |     | KSWL,KSWH (DOS)                               |
+| 3C      |     | Workbyte (ROM)                                |
+|         |     | Merge workbyte (BOOT)                         |
+|         |     | Device characteristics table address (RWTS)   |
+| 3D      |     | Sector number (ROM)                           |
+|         |     | Device characteristics table address (RWTS)   |
+| 3E,3F   |     | Address of ROM sector-read subroutine (BOOT)  |
+|         |     | Buffer address (RWTS)                         |
+| 40,41   |     | DOS image address (BOOT)                      |
+|         |     | File buffer address (DOS)                     |
+| 41      |     | Format track counter (RWTS)                   |
+| 42,43   |     | Buffer address (DOS)                          |
+| 44,45   |     | Numeric operand (DOS)                         |
+| 46,47   |     | Scratch space (RWTS)                          |
+| 48,49   |     | IOB address (RWTS)                            |
+| 4A,4B   |     | INTEGER BASIC LOMEM address (DOS)             |
+|         |     | Format diskette workspace (RWTS)              |
+| 4C,4D   |     | INTEGER BASIC HIMEM address (DOS)             |
+| 67,68   |     | APPLESOFT BASIC PROGRAM START (DOS)           |
+| 69,6A   |     | APPLESOFT BASIC VARIABLES START (DOS)         |
+| 6F,70   |     | APPLESOFT BASIC STRING START (DOS)            |
+| 73,74   |     | APPLESOFT BASIC HIMEM address (DOS)           |
+| 76      |     | APPLESOFT BASIC line number high (DOS)        |
+| AF,B0   |     | APPLESOFT BASIC PROGRAM END (DOS)             |
+| CA,CB   |     | INTEGER BASIC PROGRAM START (DOS)             |
+| CC,CD   |     | INTEGER BASIC VARIABLES END (DOS)             |
+| D6      |     | APPLESOFT BASIC PROGRAM protection flag (DOS) |
+| D8,D9   |     | INTEGER BASIC line number (DOS)               |
+|         |     | APPLESOFT BASIC ONERR (DOS)                   |
+|---------+-----+-----------------------------------------------|
+
+
+  
 * Page 03
 
 |-------------+--------------------------------------|
@@ -217,7 +270,7 @@ Apple II notes
 - http://www.textfiles.com/apple/peeks.pokes.2
 - http://www.applefritter.com/node/24236
 - http://www.easy68k.com/paulrsm/6502/index.html - Information about firmware
-- http://www-personal.umich.edu/~mressl/a2dp/index.html - Apple II documentation project
+- http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/ - Apple II documentation project
 
 * Language card
 Install in slot 0.
@@ -665,3 +718,30 @@ If track 0 has >15 sync count, the rest of the tracks will have (sync count - 2)
 tracksize 51024
 (/ 51024 8)
 6378
+
+* System disk masters
+https://github.com/cmosher01/Apple-II-System-Masters.git
+http://beagle.applearchives.com/the_software/vintage_beagle_bros_softwar/prontodos.html
+
+
+| 452f496e7c9c447052331f72f643117f | dos331/clean331sysmas.do        |
+| 452f496e7c9c447052331f72f643117f | dos331/original331sysmas.do     |
+| 452f496e7c9c447052331f72f643117f | dos331/stock331mastercreated.do |
+| 5a72964c04e4a37bb8b13a471aa046de | dos331/stock331init.do          |
+| 5ed656da29221d891d056b6b576ae2ce | dos330/stock330init.do          |
+| 6987207d16a72c60de03d8d1c5e267f3 | dos332/clean332sysmas.do        |
+| 6987207d16a72c60de03d8d1c5e267f3 | dos332/original332sysmas.do     |
+| 6987207d16a72c60de03d8d1c5e267f3 | dos332/stock332mastercreated.do |
+| 7df440bb6b3ddd8cbc44009f90a8d18f | dos330/clean330sysmas.do        |
+| 7df440bb6b3ddd8cbc44009f90a8d18f | dos330/original330sysmas.do     |
+| 7df440bb6b3ddd8cbc44009f90a8d18f | dos330/stock330mastercreated.do |
+| 9f79e87fcbcb9885a47f2f462868833f | dos332/stock332init.do          |
+| 7df440bb6b3ddd8cbc44009f90a8d18f | Apple DOS 3.3 August 1980.dsk   |
+| 452f496e7c9c447052331f72f643117f | Apple DOS 3.3 January 1983.dsk  |
+| 92e8fc0c4e79e50f2d81a14cfa55b151 | DavidDOS.dsk                    |
+| c17928ee915b9bf5c4041621fa8a0cb4 | DiversiDOS.dsk                  |
+| 6390fc84edf64dd88682b920ff88bbfa | Prontodos/Prontodos.dsk         |
+| 5b9894778b6b97d56d1199ab13b0db66 | EsDos.dsk                       |
+
+| db809f937c0de0a12cb70897ed9a72da | chivalry.dsk |
+

docs/chivalry-debug.org

@@ -0,0 +1,91 @@
+* Debugging the Chivalry disk
+Ascending memory references from $1F76.
+
+** Disassembly of routine that is overwriting from $1F76
+
+$73,$74    
+$77,$78
+$5B    
+$5C    
+$5D    
+$62    
+
+$1F51: A0 00    LDY #$00   
+$1F53: B1 73    LDA ($73),Y
+$1F55: 85 5C    STA $5C    
+$1F57: C8       INY        
+$1F58: B1 73    LDA ($73),Y
+$1F5A: 85 5B    STA $5B    
+$1F5C: C8       INY        
+$1F5D: 18       CLC        
+$1F5E: 98       TYA        
+$1F5F: 65 73    ADC $73    
+$1F61: 85 73    STA $73    
+$1F63: A9 00    LDA #$00   
+$1F65: 65 74    ADC $74    
+$1F67: 85 74    STA $74    
+$1F69: 20 9C 1D JSR $1D9C  
+$1F6C: A2 00    LDX #$00   
+$1F6E: A0 00    LDY #$00   
+$1F70: A5 5C    LDA $5C    
+$1F72: 85 5D    STA $5D    
+$1F74: B1 73    LDA ($73),Y
+$1F76: 91 77    STA ($77),Y
+$1F78: C8       INY        
+$1F79: C6 5D    DEC $5D    
+$1F7B: D0 F7    BNE $1F74  
+$1F7D: 18       CLC        
+$1F7E: 98       TYA        
+$1F7F: 65 73    ADC $73    
+$1F81: 85 73    STA $73    
+$1F83: A9 00    LDA #$00   
+$1F85: 65 74    ADC $74    
+$1F87: 85 74    STA $74    
+$1F89: E6 62    INC $62    
+$1F8B: C6 5B    DEC $5B    
+$1F8D: D0 DA    BNE $1F69  
+$1F8F: 60       RTS        
+
+** Routine it calls: $1D9C
+
+$5E    
+$61    
+$62    
+$64    
+$77    
+$78    
+
+$1D9C: A5 62    LDA $62    
+$1D9E: AA       TAX        
+$1D9F: 0A       ASL        
+$1DA0: 0A       ASL        
+$1DA1: 29 1C    AND #$1C   
+$1DA3: 85 78    STA $78    
+$1DA5: 8A       TXA        
+$1DA6: 6A       ROR        
+$1DA7: AA       TAX        
+$1DA8: 6A       ROR        
+$1DA9: 6A       ROR        
+$1DAA: 6A       ROR        
+$1DAB: 08       PHP        
+$1DAC: 29 03    AND #$03   
+$1DAE: 05 78    ORA $78    
+$1DB0: 05 5E    ORA $5E    
+$1DB2: 85 78    STA $78    
+$1DB4: 8A       TXA        
+$1DB5: 29 60    AND #$60   
+$1DB7: 85 77    STA $77    
+$1DB9: 6A       ROR        
+$1DBA: 28       PLP        
+$1DBB: 6A       ROR        
+$1DBC: 29 98    AND #$98   
+$1DBE: 05 77    ORA $77    
+$1DC0: 85 77    STA $77    
+$1DC2: A6 61    LDX $61    
+$1DC4: BD D2 1D LDA $1DD2,X
+$1DC7: 18       CLC        
+$1DC8: 65 77    ADC $77    
+$1DCA: 85 77    STA $77    
+$1DCC: BD 5E 1E LDA $1E5E,X
+$1DCF: 85 64    STA $64    
+$1DD1: 60       RTS        

goapple2.go

@@ -2,13 +2,30 @@ package goapple2
 
 import (
 	"fmt"
+	"io/ioutil"
+	"log"
+	"path/filepath"
+	"strconv"
+	"time"
 
 	"github.com/zellyn/go6502/cpu"
 	"github.com/zellyn/goapple2/cards"
 	"github.com/zellyn/goapple2/videoscan"
 )
 
-// Memory for the tests. Satisfies the cpu.Memory interface.
+type PCActionType int
+
+const (
+	ActionDumpMem PCActionType = iota + 1
+	ActionLogRegisters
+)
+
+type PCAction struct {
+	Type   PCActionType
+	String string
+}
+
+// Apple II struct
 type Apple2 struct {
 	mem             [65536]byte
 	cpu             cpu.Cpu
@@ -26,12 +43,15 @@ type Apple2 struct {
 	card12kMask     byte
 	card12kConflict bool "True if more than one card is handling the 12k ROM area"
 	card12kHandler  byte
+	cardTickerMask  byte
+	pcActions       map[uint16][]PCAction
 }
 
 func NewApple2(p videoscan.Plotter, rom []byte, charRom [2048]byte) *Apple2 {
 	a2 := Apple2{
 		// BUG(zellyn): this is not how the apple2 keyboard actually works
-		keys: make(chan byte, 16),
+		keys:      make(chan byte, 16),
+		pcActions: make(map[uint16][]PCAction),
 	}
 	copy(a2.mem[len(a2.mem)-len(rom):len(a2.mem)], rom)
 	a2.scanner = videoscan.NewScanner(&a2, p, charRom)
@@ -47,6 +67,9 @@ func (a2 *Apple2) AddCard(card cards.Card) error {
 		return fmt.Errorf("Slot %d already has a card: %s", slot, a2.cards[slot])
 	}
 	a2.cardMask |= slotbit
+	if card.WantTicker() {
+		a2.cardTickerMask |= slotbit
+	}
 	a2.cards[slot] = card
 	return nil
 }
@@ -75,20 +98,28 @@ func (a2 *Apple2) handleC00X(address uint16, value byte, write bool) byte {
 		}
 		switch address {
 		case 0xC050: // GRAPHICS
+			fmt.Printf("$%04X: GRAPHICS\n", a2.cpu.PC())
 			a2.scanner.SetGraphics(true)
 		case 0xC051: // TEXT
+			fmt.Printf("$%04X: NO GRAPHICS\n", a2.cpu.PC())
 			a2.scanner.SetGraphics(false)
 		case 0xC052: // NOMIX
+			fmt.Printf("$%04X: NOMIX\n", a2.cpu.PC())
 			a2.scanner.SetMix(false)
 		case 0xC053: // MIX
+			fmt.Printf("$%04X: MIX\n", a2.cpu.PC())
 			a2.scanner.SetMix(true)
 		case 0xC054: // PAGE 1
+			fmt.Printf("$%04X: PAGE1\n", a2.cpu.PC())
 			a2.scanner.SetPage(1)
 		case 0xC055: // PAGE 2
+			fmt.Printf("$%04X: PAGE2\n", a2.cpu.PC())
 			a2.scanner.SetPage(2)
 		case 0xC056: // LORES
+			fmt.Printf("$%04X: LORES\n", a2.cpu.PC())
 			a2.scanner.SetHires(false)
 		case 0xC057: // HIRES
+			fmt.Printf("$%04X: HIRES\n", a2.cpu.PC())
 			a2.scanner.SetHires(true)
 		}
 	}
@@ -197,12 +228,33 @@ func (a2 *Apple2) Keypress(key byte) {
 	a2.keys <- key | 0x80
 }
 
+func (a2 *Apple2) AddPCAction(address uint16, action PCAction) {
+	a2.pcActions[address] = append(a2.pcActions[address], action)
+}
+
 func (a2 *Apple2) Step() error {
+	if actions, ok := a2.pcActions[a2.cpu.PC()]; ok {
+		for _, action := range actions {
+			switch action.Type {
+			case ActionDumpMem:
+				a2.DumpRAM(action.String, true)
+			case ActionLogRegisters:
+				a2.LogRegisters()
+			}
+		}
+	}
 	return a2.cpu.Step()
 }
 
 func (a2 *Apple2) Tick() {
 	a2.scanner.Scan1()
+	tickerMask := a2.cardTickerMask
+	for i := 0; i < 8 && tickerMask > 0; i++ {
+		if tickerMask&1 == 1 {
+			a2.cards[i].Tick()
+		}
+		tickerMask >>= 1
+	}
 }
 
 func (a2 *Apple2) Quit() {
@@ -245,3 +297,24 @@ func (a2 *Apple2) Handle12k(onOff bool, slot byte) {
 		}
 	}
 }
+
+func (a2 *Apple2) LogRegisters() {
+	c := a2.cpu
+	log.Printf("Registers: PC=$%04X A=$%02X X=$%02X Y=$%02X SP=$%02X P=$%02X=$%08b",
+		c.PC(), c.A(), c.X(), c.Y(), c.SP(), c.P(), c.P())
+}
+func (a2 *Apple2) DumpRAM(filename string, addTimestamp bool) error {
+	f := filename
+	if addTimestamp {
+		ts := "-" + strconv.FormatInt(time.Now().UnixNano(), 10)
+		if ext := filepath.Ext(filename); ext == "" {
+			f = filename + ts
+		} else {
+			dir, file := filepath.Split(filename[:len(filename)-len(ext)])
+			f = dir + file + ts + ext
+		}
+	}
+	log.Printf("Dumping RAM to %s", f)
+	a2.LogRegisters()
+	return ioutil.WriteFile(f, a2.mem[:0xC000], 0644)
+}

sdl/sdl.go

@@ -261,6 +261,7 @@ func (s SdlPlotter) OncePerFrame() {
 }
 
 func typeProgram(a2 *goapple2.Apple2) {
+	return
 	lines := []string{
 		"10 GR",
 		"20 POKE -16302,0",
@@ -272,6 +273,14 @@ func typeProgram(a2 *goapple2.Apple2) {
 		"80 NEXT",
 		"RUN",
 	}
+	lines = []string{
+		"10 HGR2",
+		"20 FOR I = 0 to 7",
+		"30 HCOLOR=7-I",
+		"40 HPLOT I*10, 0 TO 191 + I*10, 191",
+		"50 NEXT",
+		"RUN",
+	}
 	for _, line := range lines {
 		for _, ch := range line {
 			a2.Keypress(byte(ch))
@@ -315,10 +324,11 @@ func RunEmulator() {
 		log.Fatal(err)
 	}
 	disk1 := disk.NewNybble()
+	// if err = disk1.LoadDosDisk("../data/disks/spedtest.dsk"); err != nil {
+	// if err = disk1.LoadDosDisk("../data/disks/dung_beetles.dsk"); err != nil {
 	if err = disk1.LoadDosDisk("../data/disks/chivalry.dsk"); err != nil {
 		log.Fatal(err)
 	}
-	disk1.SetHalfTrack(50)
 	diskCard.LoadDisk(disk1, 0)
 
 	steps := *steplimit
@@ -332,7 +342,10 @@ func RunEmulator() {
 		defer pprof.StopCPUProfile()
 	}
 
-	go typeProgram(a2)
+	a2.AddPCAction(0xC6EB, goapple2.PCAction{goapple2.ActionDumpMem, "chivalry-dump.bin"})
+	a2.AddPCAction(0x1F76, goapple2.PCAction{goapple2.ActionDumpMem, "chivalry-dump.bin"})
+
+	// go typeProgram(a2)
 
 	for !a2.Done {
 		err := a2.Step()

videoscan/videoscan.go

@@ -96,15 +96,19 @@ func (s *Scanner) inc() {
 var last [192][40]uint16
 
 func (s *Scanner) Scan1() {
-	m := s.m.RamRead(s.address())
+	address := s.address()
+	if address >= 0xC000 {
+		fmt.Printf("\n\n\nWOAH! $%04X\n\n\n", address)
+	}
+	m := s.m.RamRead(address)
 	row, column := s.row(), s.column()
 	_, _, _ = m, row, column
 	var data uint16
 	switch {
 	case !s.graphics || (s.mix && s.lastFour):
-		data = s.textData(m, row, column)
+		data = s.textData(m, row)
 	case s.hires:
-		data = s.hiresData(m, row, column)
+		data = s.hiresData(m)
 	default: // lores
 		data = s.loresData(m, row, column)
 	}
@@ -112,6 +116,9 @@ func (s *Scanner) Scan1() {
 	if !s.hbl && !s.vbl {
 		change := last[row][column] != (data | s.graphicsBit)
 		if change || s.lastChange {
+			// if row <= 8 && column == 0 {
+			// 	fmt.Printf("%d,%d: RawData=%02X, Data=%04X\n", row, column, m, data)
+			// }
 			s.plotter.Plot(PlotData{
 				Row:        byte(row),
 				Column:     byte(column),
@@ -218,7 +225,7 @@ func (s *Scanner) SetPage(page int) {
 	}
 }
 
-func (s *Scanner) textData(m byte, row int, column int) uint16 {
+func (s *Scanner) textData(m byte, row int) uint16 {
 	line := s.rom[int(m)*8+((row+800)%8)]
 	// Invert if flash
 	if (m^0x80)&line&s.flasher > 127 {
@@ -226,7 +233,7 @@ func (s *Scanner) textData(m byte, row int, column int) uint16 {
 	}
 	line &= 0x7f // Mask out high bit
 	// Now it's just like hires data
-	return s.hiresData(line, row, column)
+	return s.hiresData(line)
 }
 
 // Double each bit to go from pixel info to color info
@@ -249,11 +256,11 @@ var HIRES_DOUBLES = [128]uint16{
 	0x3FC0, 0x3FC3, 0x3FCC, 0x3FCF, 0x3FF0, 0x3FF3, 0x3FFC, 0x3FFF,
 }
 
-func (s *Scanner) hiresData(m byte, row int, column int) uint16 {
+func (s *Scanner) hiresData(m byte) uint16 {
 	if m < 128 {
 		return HIRES_DOUBLES[m]
 	}
-	return ((HIRES_DOUBLES[m&0x7f] << 1) & 0x3ff) | s.lastBit
+	return ((HIRES_DOUBLES[m&0x7f] << 1) & 0x3fff) | s.lastBit
 }
 
 func (s *Scanner) loresData(m byte, row int, column int) uint16 {

videoscan/videoscan_test.go

@@ -228,3 +228,43 @@ func TestSpecificLocationAddresses(t *testing.T) {
 		}
 	}
 }
+
+func TestHiresConversion(t *testing.T) {
+	var m K64
+	var f fakePlotter
+	s := NewScanner(&m, &f, [2048]byte{})
+
+	s.SetMix(false)
+	s.SetGraphics(true)
+	s.SetHires(true)
+
+	hiresIn0 := []byte{0x03, 0x06, 0x0C, 0x18, 0x30}
+	hiresOut0 := []uint16{0xf, 0x3c, 0xf0, 0x3c0, 0xf00}
+	hiresIn1 := []byte{0x83, 0x86, 0x8C, 0x98, 0xB0}
+	hiresOut1 := []uint16{0x1e, 0x78, 0x1e0, 0x780, 0x1e00}
+	for i := range hiresIn0 {
+		s.lastBit = 0
+		out := s.hiresData(hiresIn0[i])
+		if out != hiresOut0[i] {
+			t.Errorf("Expected hiresData(0x%02X) to be %04X, got %04X", hiresIn0[i], hiresOut0[i], out)
+		}
+		s.lastBit = 1
+		out = s.hiresData(hiresIn0[i])
+		if out != hiresOut0[i] {
+			t.Errorf("Expected hiresData(0x%02X) to be %04X, got %04X", hiresIn0[i], hiresOut0[i], out)
+		}
+	}
+
+	for i := range hiresIn1 {
+		s.lastBit = 0
+		out := s.hiresData(hiresIn1[i])
+		if out != hiresOut1[i] {
+			t.Errorf("Expected hiresData(0x%02X) lb=0 to be %04X, got %04X", hiresIn1[i], hiresOut1[i], out)
+		}
+		s.lastBit = 1
+		out = s.hiresData(hiresIn1[i])
+		if out != hiresOut1[i]|1 {
+			t.Errorf("Expected hiresData(0x%02X) lb=1 to be %04X, got %04X", hiresIn1[i], hiresOut1[i]|1, out)
+		}
+	}
+}