izapple2/core6502/memory.go
2020-08-16 15:41:21 +02:00

55 lines
1.3 KiB
Go

package core6502
import "io/ioutil"
// Memory represents the addressable space of the processor
type Memory interface {
Peek(address uint16) uint8
Poke(address uint16, value uint8)
// PeekCode can bu used to optimize the memory manager to requests with more
// locality. It must return the same as a call to Peek()
PeekCode(address uint16) uint8
}
func getWord(m Memory, address uint16) uint16 {
return uint16(m.Peek(address)) + 0x100*uint16(m.Peek(address+1))
}
func getZeroPageWord(m Memory, address uint8) uint16 {
return uint16(m.Peek(uint16(address))) + 0x100*uint16(m.Peek(uint16(address+1)))
}
// FlatMemory puts RAM on the 64Kb addressable by the processor
type FlatMemory struct {
data [65536]uint8
}
// Peek returns the data on the given address
func (m *FlatMemory) Peek(address uint16) uint8 {
return m.data[address]
}
// PeekCode returns the data on the given address
func (m *FlatMemory) PeekCode(address uint16) uint8 {
return m.data[address]
}
// Poke sets the data at the given address
func (m *FlatMemory) Poke(address uint16, value uint8) {
m.data[address] = value
}
func (m *FlatMemory) loadBinary(filename string) error {
bytes, err := ioutil.ReadFile(filename)
if err != nil {
return err
}
for i, v := range bytes {
m.Poke(uint16(i), uint8(v))
}
return nil
}