Refactor ROM loading. Preparation for alt roms.

apple2Setup.go

@@ -3,10 +3,11 @@ package apple2
 import "github.com/ivanizag/apple2/core6502"
 
 // NewApple2 instantiates an apple2
-func NewApple2(romFile string, charRomFile string, clockMhz float64,
+func NewApple2(charRomFile string, clockMhz float64,
 	isColor bool, fastMode bool, panicSS bool) *Apple2 {
+
 	var a Apple2
-	a.mmu = newMemoryManager(&a, romFile)
+	a.mmu = newMemoryManager(&a)
 	a.cpu = core6502.NewNMOS6502(a.mmu)
 	if charRomFile != "" {
 		a.cg = NewCharacterGenerator(charRomFile)
@@ -35,6 +36,34 @@ func (a *Apple2) insertCard(c card, slot int) {
 	a.cards[slot] = c
 }
 
+const (
+	apple2RomSize  = 12 * 1024
+	apple2eRomSize = 16 * 1024
+)
+
+// LoadRom loads a standard Apple2+ or 2e ROM
+func (a *Apple2) LoadRom(filename string) {
+	data := loadResource(filename)
+	size := len(data)
+	if size != apple2RomSize && size != apple2eRomSize {
+		panic("Rom size not supported")
+	}
+
+	romStart := 0
+	mmu := a.mmu
+	if size == apple2eRomSize {
+		// The extra 4kb ROM is first in the rom file.
+		// It starts with 256 unused bytes not mapped to 0xc000.
+		a.isApple2e = true
+		extraRomSize := apple2eRomSize - apple2RomSize
+		mmu.physicalROMe = newMemoryRange(0xc000, data[0:extraRomSize])
+		romStart = extraRomSize
+	}
+
+	mmu.physicalROM = newMemoryRange(0xd000, data[romStart:])
+	mmu.resetRomPaging()
+}
+
 // AddDisk2 insterts a DiskII controller
 func (a *Apple2) AddDisk2(slot int, diskRomFile string, diskImage string) {
 	var c cardDisk2

apple2main.go

@@ -68,7 +68,8 @@ func MainApple() *Apple2 {
 		return nil
 	}
 
-	a := NewApple2(*romFile, *charRomFile, *cpuClock, !*mono, *fastDisk, *panicSS)
+	a := NewApple2(*charRomFile, *cpuClock, !*mono, *fastDisk, *panicSS)
+	a.LoadRom(*romFile)
 	if *languageCardSlot >= 0 {
 		a.AddLanguageCard(*languageCardSlot)
 	}

memoryManager.go

@@ -101,46 +101,17 @@ func (mmu *memoryManager) resetBaseRamPaging() {
 	mmu.setPages(0x00, 0xbf, mmu.physicalMainRAM)
 }
 
-func newMemoryManager(a *Apple2, romFile string) *memoryManager {
+func newMemoryManager(a *Apple2) *memoryManager {
 	var mmu memoryManager
 	mmu.apple2 = a
 
 	ram := make([]uint8, 0xc000) // Reserve 48kb
 	mmu.physicalMainRAM = newMemoryRange(0, ram)
-
-	mmu.loadRom(romFile)
 	mmu.resetBaseRamPaging()
-	mmu.resetRomPaging()
 
 	return &mmu
 }
 
-const (
-	apple2RomSize  = 12 * 1024
-	apple2eRomSize = 16 * 1024
-)
-
-func (mmu *memoryManager) loadRom(filename string) {
-	data := loadResource(filename)
-	size := len(data)
-	if size != apple2RomSize && size != apple2eRomSize {
-		panic("Rom size not supported")
-	}
-
-	a := mmu.apple2
-	romStart := 0
-	if size == apple2eRomSize {
-		// The extra 4kb ROM is first in the rom file.
-		// It starts with 256 unused bytes not mapped to 0xc000.
-		a.isApple2e = true
-		extraRomSize := apple2eRomSize - apple2RomSize
-		mmu.physicalROMe = newMemoryRange(0xc000, data[0:extraRomSize])
-		romStart = extraRomSize
-	}
-
-	mmu.physicalROM = newMemoryRange(0xd000, data[romStart:])
-}
-
 func (mmu *memoryManager) save(w io.Writer) {
 	mmu.physicalMainRAM.save(w)
 }