izapple2/ioC0Page.go

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package apple2
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import (
"encoding/binary"
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"fmt"
"io"
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)
type ioC0Page struct {
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softSwitchesR [256]softSwitchR
softSwitchesW [256]softSwitchW
softSwitchesData [128]uint8
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keyboard KeyboardProvider
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speaker SpeakerProvider
apple2 *Apple2
}
type softSwitchR func(io *ioC0Page) uint8
type softSwitchW func(io *ioC0Page, value uint8)
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// KeyboardProvider declares the keyboard implementation requirements
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type KeyboardProvider interface {
GetKey(strobe bool) (key uint8, ok bool)
}
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// SpeakerProvider declares the speaker implementation requirements
type SpeakerProvider interface {
// Click receives a speaker click. The argument is the CPU cycle when it is generated
Click(cycle uint64)
}
// See https://www.kreativekorp.com/miscpages/a2info/iomemory.shtml
// See https://stason.org/TULARC/pc/apple2/programmer/004-I-d-like-to-do-some-serious-Apple-II-programming-Whe.html
const (
ssOn uint8 = 0x80
ssOff uint8 = 0x00
)
func newIoC0Page(a *Apple2) *ioC0Page {
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var io ioC0Page
io.apple2 = a
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addApple2SoftSwitches(&io)
if a.isApple2e {
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addApple2ESoftSwitches(&io)
}
return &io
}
func (p *ioC0Page) save(w io.Writer) {
binary.Write(w, binary.BigEndian, p.softSwitchesData)
}
func (p *ioC0Page) load(r io.Reader) {
binary.Read(r, binary.BigEndian, &p.softSwitchesData)
}
func (p *ioC0Page) addSoftSwitchRW(address uint8, ss softSwitchR) {
p.addSoftSwitchR(address, ss)
p.addSoftSwitchW(address, func(p *ioC0Page, _ uint8) {
ss(p)
})
}
func (p *ioC0Page) addSoftSwitchR(address uint8, ss softSwitchR) {
if p.softSwitchesR[address] != nil {
fmt.Printf("Addresss 0x0c%02x is already assigned for read", address)
}
p.softSwitchesR[address] = ss
}
func (p *ioC0Page) addSoftSwitchW(address uint8, ss softSwitchW) {
if p.softSwitchesW[address] != nil {
fmt.Printf("Addresss 0x0c%02x is already assigned for write", address)
}
p.softSwitchesW[address] = ss
}
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func (p *ioC0Page) isSoftSwitchActive(ioFlag uint8) bool {
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return (p.softSwitchesData[ioFlag] & ssOn) == ssOn
}
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func (p *ioC0Page) setKeyboardProvider(kb KeyboardProvider) {
p.keyboard = kb
}
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func (p *ioC0Page) setSpeakerProvider(s SpeakerProvider) {
p.speaker = s
}
func (p *ioC0Page) peek(address uint16) uint8 {
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//fmt.Printf("Peek on $%02x\n", address)
pageAddress := uint8(address)
ss := p.softSwitchesR[pageAddress]
if ss == nil {
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if p.apple2.panicSS {
panic(fmt.Sprintf("Unknown softswitch on read to 0xC0%02x", pageAddress))
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}
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return 0
}
return ss(p)
}
func (p *ioC0Page) poke(address uint16, value uint8) {
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//fmt.Printf("Poke on $%02x with %02x\n", address, value)
pageAddress := uint8(address)
ss := p.softSwitchesW[pageAddress]
if ss == nil {
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if p.apple2.panicSS {
panic(fmt.Sprintf("Unknown softswitch on write to 0xC0%02x", pageAddress))
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}
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return
}
ss(p, value)
}