added EF cartridge mapper

README.md

@@ -820,6 +820,7 @@ Modern formats supported:
 * 3E
 * 3E+
 * DF
+* EF
 * DPC+
 * CDF (including CDFJ and CDFJ+)
 
@@ -876,7 +877,9 @@ seem to be documented anywhere accept in the Stella source.
 a comment in the fingerprint.go file says I did.
 
 * As a reference for the audio implementation (the 6502.ts project was also
-  referenced for this reason)
+  referenced for this reason).
+
+* The EF cartridge format.
 
 Many notes and clues from the AtariAge message boards. Most significantly the
 following threads proved very useful indeed:

cartridgeloader/loader.go

@@ -191,6 +191,8 @@ func NewLoader(filename string, mapping string) (Loader, error) {
 			fallthrough // synonym for 3E+
 		case ".3E+":
 			fallthrough
+		case ".EF":
+			fallthrough
 		case ".SB":
 			fallthrough
 		case ".DPC":

hardware/memory/cartridge/cartridge.go

@@ -275,6 +275,8 @@ func (cart *Cartridge) Attach(cartload cartridgeloader.Loader) error {
 		fallthrough
 	case "3E+":
 		cart.mapper, err = new3ePlus(cart.instance, cartload.Data)
+	case "EF":
+		cart.mapper, err = newEF(cart.instance, cartload.Data)
 	case "SB":
 		cart.mapper, err = newSuperbank(cart.instance, cartload.Data)
 	case "DPC":

hardware/memory/cartridge/fingerprint.go

@@ -341,7 +341,12 @@ func (cart *Cartridge) fingerprint(cartload cartridgeloader.Loader) error {
 		}
 
 	case 65536:
-		return curated.Errorf("65536 bytes not yet supported")
+		// EF is the only 64k cartridge format that I'm aware of so there is no
+		// need for fingerprinting
+		cart.mapper, err = newEF(cart.instance, cartload.Data)
+		if err != nil {
+			return err
+		}
 
 	case 131072:
 		cart.mapper, err = fingerprint128k(cartload.Data)(cart.instance, cartload.Data)

hardware/memory/cartridge/mapper_ef.go

@@ -0,0 +1,210 @@
+// This file is part of Gopher2600.
+//
+// Gopher2600 is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Gopher2600 is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Gopher2600.  If not, see <https://www.gnu.org/licenses/>.
+
+package cartridge
+
+import (
+	"fmt"
+
+	"github.com/jetsetilly/gopher2600/curated"
+	"github.com/jetsetilly/gopher2600/hardware/instance"
+	"github.com/jetsetilly/gopher2600/hardware/memory/cartridge/mapper"
+	"github.com/jetsetilly/gopher2600/hardware/memory/cpubus"
+	"github.com/jetsetilly/gopher2600/hardware/memory/memorymap"
+)
+
+type ef struct {
+	instance *instance.Instance
+
+	mappingID   string
+	description string
+
+	// ef cartridges have 3 banks of 4096 bytes
+	bankSize int
+	banks    [][]uint8
+
+	// rewindable state
+	state *efState
+}
+
+func newEF(instance *instance.Instance, data []byte) (mapper.CartMapper, error) {
+	cart := &ef{
+		instance:    instance,
+		mappingID:   "EF",
+		description: "16 bank 64k",
+		bankSize:    4096,
+		state:       newEFstate(),
+	}
+
+	if len(data) != cart.bankSize*cart.NumBanks() {
+		return nil, curated.Errorf("EF: %v", "wrong number of bytes in the cartridge data")
+	}
+
+	cart.banks = make([][]uint8, cart.NumBanks())
+
+	for k := 0; k < cart.NumBanks(); k++ {
+		cart.banks[k] = make([]uint8, cart.bankSize)
+		offset := k * cart.bankSize
+		copy(cart.banks[k], data[offset:offset+cart.bankSize])
+	}
+
+	return cart, nil
+}
+
+// MappedBanks implements the mapper.CartMapper interface.
+func (cart *ef) MappedBanks() string {
+	return fmt.Sprintf("Bank: %d", cart.state.bank)
+}
+
+// ID implements the mapper.CartMapper interface.
+func (cart *ef) ID() string {
+	return cart.mappingID
+}
+
+// Snapshot implements the mapper.CartMapper interface.
+func (cart *ef) Snapshot() mapper.CartMapper {
+	n := *cart
+	n.state = cart.state.Snapshot()
+	return &n
+}
+
+// Plumb implements the mapper.CartMapper interface.
+func (cart *ef) Plumb() {
+}
+
+// Reset implements the cartMapper interface.
+func (cart *ef) Reset() {
+	cart.state.bank = 0 //len(cart.banks) - 1
+}
+
+// Read implements the mapper.CartMapper interface.
+func (cart *ef) Read(addr uint16, passive bool) (uint8, error) {
+	cart.bankswitch(addr, passive)
+
+	return cart.banks[cart.state.bank][addr], nil
+}
+
+// Write implements the mapper.CartMapper interface.
+func (cart *ef) Write(addr uint16, data uint8, passive bool, poke bool) error {
+	if cart.bankswitch(addr, passive) {
+		return nil
+	}
+
+	if poke {
+		cart.banks[cart.state.bank][addr] = data
+		return nil
+	}
+
+	return curated.Errorf("EF: %v", curated.Errorf(cpubus.AddressError, addr))
+}
+
+// bankswitch on hotspot access.
+func (cart *ef) bankswitch(addr uint16, passive bool) bool {
+	if addr >= 0x0fe0 && addr <= 0x0fef {
+		if passive {
+			return true
+		}
+		cart.state.bank = int(addr & 0x000f)
+		return true
+	}
+	return false
+}
+
+// NumBanks implements the mapper.CartMapper interface.
+func (cart *ef) NumBanks() int {
+	return 16
+}
+
+// GetBank implements the mapper.CartMapper interface.
+func (cart *ef) GetBank(addr uint16) mapper.BankInfo {
+	// ef cartridges are like atari cartridges in that the entire address
+	// space points to the selected bank
+	return mapper.BankInfo{Number: cart.state.bank, IsRAM: addr <= 0x00ff}
+}
+
+// Patch implements the mapper.CartMapper interface.
+func (cart *ef) Patch(offset int, data uint8) error {
+	if offset >= cart.bankSize*len(cart.banks) {
+		return curated.Errorf("EF: %v", fmt.Errorf("patch offset too high (%v)", offset))
+	}
+
+	bank := offset / cart.bankSize
+	offset %= cart.bankSize
+	cart.banks[bank][offset] = data
+	return nil
+}
+
+// Listen implements the mapper.CartMapper interface.
+func (cart *ef) Listen(_ uint16, _ uint8) {
+}
+
+// Step implements the mapper.CartMapper interface.
+func (cart *ef) Step(_ float32) {
+}
+
+// IterateBank implements the mapper.CartMapper interface.
+func (cart *ef) CopyBanks() []mapper.BankContent {
+	c := make([]mapper.BankContent, len(cart.banks))
+	for b := 0; b < len(cart.banks); b++ {
+		c[b] = mapper.BankContent{Number: b,
+			Data:    cart.banks[b],
+			Origins: []uint16{memorymap.OriginCart},
+		}
+	}
+	return c
+}
+
+// ReadHotspots implements the mapper.CartHotspotsBus interface.
+func (cart *ef) ReadHotspots() map[uint16]mapper.CartHotspotInfo {
+	return map[uint16]mapper.CartHotspotInfo{
+		0x1fe0: {Symbol: "BANK0", Action: mapper.HotspotBankSwitch},
+		0x1fe1: {Symbol: "BANK1", Action: mapper.HotspotBankSwitch},
+		0x1fe2: {Symbol: "BANK2", Action: mapper.HotspotBankSwitch},
+		0x1fe3: {Symbol: "BANK3", Action: mapper.HotspotBankSwitch},
+		0x1fe4: {Symbol: "BANK4", Action: mapper.HotspotBankSwitch},
+		0x1fe5: {Symbol: "BANK5", Action: mapper.HotspotBankSwitch},
+		0x1fe6: {Symbol: "BANK6", Action: mapper.HotspotBankSwitch},
+		0x1fe7: {Symbol: "BANK7", Action: mapper.HotspotBankSwitch},
+		0x1fe8: {Symbol: "BANK8", Action: mapper.HotspotBankSwitch},
+		0x1fe9: {Symbol: "BANK9", Action: mapper.HotspotBankSwitch},
+		0x1fea: {Symbol: "BANK10", Action: mapper.HotspotBankSwitch},
+		0x1feb: {Symbol: "BANK11", Action: mapper.HotspotBankSwitch},
+		0x1fec: {Symbol: "BANK12", Action: mapper.HotspotBankSwitch},
+		0x1fed: {Symbol: "BANK13", Action: mapper.HotspotBankSwitch},
+		0x1fee: {Symbol: "BANK14", Action: mapper.HotspotBankSwitch},
+		0x1fef: {Symbol: "BANK15", Action: mapper.HotspotBankSwitch},
+	}
+}
+
+// WriteHotspots implements the mapper.CartHotspotsBus interface.
+func (cart *ef) WriteHotspots() map[uint16]mapper.CartHotspotInfo {
+	return cart.ReadHotspots()
+}
+
+// rewindable state for the CBS cartridge.
+type efState struct {
+	// identifies the currently selected bank
+	bank int
+}
+
+func newEFstate() *efState {
+	return &efState{}
+}
+
+// Snapshot implements the mapper.CartMapper interface.
+func (s *efState) Snapshot() *efState {
+	n := *s
+	return &n
+}