Support for character generator pages. F10 to change page.

README.md

@@ -84,6 +84,7 @@ Line:
 - F6: Toggle between NTSC color TV and green phosphor monochrome monitor
 - F7: Save current state to disk
 - F8: Restore state from disk
+- F10: Cycle character generator codepages. Only if the character generator ROM has more than one 2Kb pages.
 - F12: Save a screen snapshot to a file `snapshot.png`
 
 Only valid on SDL mode
@@ -91,6 +92,8 @@ Only valid on SDL mode
 ### Command line options
 
 ```
+  -base64a
+        setup a Base64A clone
   -charRom string
     	rom file for the character generator (default "<internal>/Apple2rev7CharGen.rom")
   -disk string

apple2.go

@@ -13,6 +13,7 @@ import (
 
 // Apple2 represents all the components and state of the emulated machine
 type Apple2 struct {
+	Name                string
 	cpu                 *core6502.State
 	mmu                 *memoryManager
 	io                  *ioC0Page
@@ -84,6 +85,8 @@ const (
 	CommandLoadState
 	// CommandDumpDebugInfo dumps usefull info
 	CommandDumpDebugInfo
+	// CommandNextCharGenPage cycles the CharGen page if several
+	CommandNextCharGenPage
 )
 
 // SendCommand enqueues a command to the emulator thread
@@ -111,6 +114,9 @@ func (a *Apple2) executeCommand(command int) {
 		a.load("apple2.state")
 	case CommandDumpDebugInfo:
 		a.dumpDebugInfo()
+	case CommandNextCharGenPage:
+		a.cg.nextPage()
+		fmt.Printf("Chargen page %v\n", a.cg.page)
 	}
 }
 

apple2Setup.go

@@ -7,6 +7,7 @@ func NewApple2(charRomFile string, clockMhz float64,
 	isColor bool, fastMode bool, panicSS bool) *Apple2 {
 
 	var a Apple2
+	a.Name = "Apple ][+"
 	a.mmu = newMemoryManager(&a)
 	a.cpu = core6502.NewNMOS6502(a.mmu)
 	if charRomFile != "" {

apple2main.go

@@ -66,13 +66,6 @@ func MainApple() *Apple2 {
 	)
 	flag.Parse()
 
-	if *dumpChars {
-		cg := NewCharacterGenerator(*charRomFile)
-		cg.Dump()
-		os.Exit(0)
-		return nil
-	}
-
 	a := NewApple2(*charRomFile, *cpuClock, !*mono, *fastDisk, *panicSS)
 	if *base64a {
 		NewBase64a(a)
@@ -92,5 +85,11 @@ func MainApple() *Apple2 {
 	//a.AddCardInOut(2)
 	//a.AddCardLogger(4)
 
+	if *dumpChars {
+		a.cg.Dump()
+		os.Exit(0)
+		return nil
+	}
+
 	return a
 }

apple2sdl/main.go

@@ -26,7 +26,7 @@ func SDLRun(a *apple2.Apple2) {
 
 	defer window.Destroy()
 	defer renderer.Destroy()
-	window.SetTitle("Apple2")
+	window.SetTitle(a.Name)
 
 	kp := newSDLKeyBoard(a)
 	a.SetKeyboardProvider(kp)

apple2sdl/sdlKeyboard.go

@@ -101,6 +101,8 @@ func (k *sdlKeyboard) putKey(keyEvent *sdl.KeyboardEvent) {
 		k.a.SendCommand(apple2.CommandLoadState)
 	case sdl.K_F9:
 		k.a.SendCommand(apple2.CommandDumpDebugInfo)
+	case sdl.K_F10:
+		k.a.SendCommand(apple2.CommandNextCharGenPage)
 	case sdl.K_F12:
 		apple2.SaveSnapshot(k.a, "snapshot.png")
 	}

base64a.go

@@ -15,14 +15,32 @@ type Base64a struct {
 
 // NewBase64a instantiates an apple2
 func NewBase64a(a *Apple2) *Base64a {
-
 	var b Base64a
 	b.a = a
+	a.Name = "Base 64A"
 	b.loadRom()
 
+	// Configure the character generator
+	if !a.cg.customRom {
+		a.cg.load("<internal>/BASE64A_ROM7_CharGen.BIN")
+	}
+	a.cg.setColumnMap(base64aCharGenColumnsMap)
+	a.cg.setPage(1)
+
 	return &b
 }
 
+func base64aCharGenColumnsMap(column int) int {
+	bit := column + 2
+	// Weird positions
+	if column == 6 {
+		bit = 2
+	} else if column == 0 {
+		bit = 1
+	}
+	return bit
+}
+
 const (
 	// There are 6 ROM chips. Each can have 4Kb or 8Kb. They can fill
 	// 2 or 4 banks with 2kb windows.
@@ -87,7 +105,7 @@ func (b *Base64a) loadRom() {
 
 func (b *Base64a) changeRomBank(bank uint8) {
 	b.romBank = bank
-	fmt.Printf("Change to ROM bank #%v\n", b.romBank)
+	//fmt.Printf("Change to ROM bank #%v\n", b.romBank)
 	b.a.mmu.physicalROM = b.romBanks[b.romBank]
 	b.a.mmu.resetRomPaging() // If rom was not active. This is going to far?
 }

characterGenerator.go

@@ -11,11 +11,17 @@ import (
 
 // CharacterGenerator represents the ROM wth the characters bitmaps
 type CharacterGenerator struct {
-	data []uint8
+	data      []uint8
+	customRom bool
+	columnMap charColumnMap
+	page      int
 }
 
+type charColumnMap func(column int) int
+
 const (
-	rev7CharGenSize = 2048
+	rev7CharGenSize   = 2048
+	defaultCharGenROM = "<internal>/Apple2rev7CharGen.rom"
 )
 
 // NewCharacterGenerator instantiates a new Character Generator with the rom on the file given
@@ -26,27 +32,50 @@ func NewCharacterGenerator(filename string) *CharacterGenerator {
 }
 
 func (cg *CharacterGenerator) load(filename string) {
+	cg.customRom = !isInternalResource(filename)
 	bytes := loadResource(filename)
 	size := len(bytes)
-	if size != rev7CharGenSize {
+	if size < rev7CharGenSize {
 		panic("Character ROM size not supported")
 	}
 	cg.data = bytes
 }
 
-func (cg *CharacterGenerator) getPixel(char uint8, row int, column int) bool {
-	bits := cg.data[int(char)*8+row]
-	bit := bits >> (uint(6 - column)) & 1
-	return bit == 1
+func (cg *CharacterGenerator) setColumnMap(columnMap charColumnMap) {
+	// Regular Apple II uses bits 6 to 0 but some clones have other mappings
+	cg.columnMap = columnMap
 }
 
-func (cg *CharacterGenerator) dumpCharFast(char uint8) {
+func (cg *CharacterGenerator) setPage(page int) {
+	// Some clones had a switch to change codepage with extra characters
+	pages := len(cg.data) / rev7CharGenSize
+	cg.page = page % pages
+}
+
+func (cg *CharacterGenerator) nextPage() {
+	cg.setPage(cg.page + 1)
+}
+
+func (cg *CharacterGenerator) getPixel(char uint8, row int, column int) bool {
+	bits := cg.data[int(char)*8+row+cg.page*rev7CharGenSize]
+	var bit int
+	if cg.columnMap != nil {
+		bit = cg.columnMap(column)
+	} else {
+		// Standard Apple 2 mapping
+		bit = 6 - column
+	}
+	value := bits >> uint(bit) & 1
+	return value == 1
+}
+
+func (cg *CharacterGenerator) dumpCharRaw(char int) {
 	base := int(char) * 8
 	fmt.Printf("Char: %v\n---------\n", char)
 	for i := 0; i < 8; i++ {
 		fmt.Print("|")
 		b := cg.data[base+i]
-		for j := 6; j >= 0; j-- {
+		for j := 0; j < 8; j++ {
 			if (b>>uint(j))&1 == 1 {
 				fmt.Print("#")
 			} else {
@@ -76,7 +105,12 @@ func (cg *CharacterGenerator) dumpChar(char uint8) {
 
 // Dump to sdtout all the character maps
 func (cg *CharacterGenerator) Dump() {
-	for i := 0; i < 256; i++ {
-		cg.dumpChar(uint8(i))
+	pages := len(cg.data) / rev7CharGenSize
+	for p := 0; p < pages; p++ {
+		cg.setPage(p)
+		for i := 0; i < 256; i++ {
+			cg.dumpChar(uint8(i))
+			//cg.dumpCharRaw(int(i))
+		}
 	}
 }

resources.go

@@ -13,9 +13,13 @@ const (
 	internalPrefix = "<internal>/"
 )
 
+func isInternalResource(filename string) bool {
+	return strings.HasPrefix(filename, internalPrefix)
+}
+
 func loadResource(filename string) []uint8 {
 	var file io.Reader
-	if strings.HasPrefix(filename, internalPrefix) {
+	if isInternalResource(filename) {
 		// load from embedded resource
 		resource := strings.TrimPrefix(filename, internalPrefix)
 		resourceFile, err := romdumps.Assets.Open(resource)