Sketch out some of the easy stuff.

Machines/Apple/AppleII/AppleII.cpp

@@ -24,6 +24,7 @@
 #include "DiskIICard.hpp"
 #include "Joystick.hpp"
 #include "LanguageCardSwitches.hpp"
+#include "SCSICard.hpp"
 #include "Video.hpp"
 
 #include "../../../Analyser/Static/AppleII/Target.hpp"
@@ -460,10 +461,15 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			const bool has_disk_controller = target.disk_controller != Target::DiskController::None;
 			const bool is_sixteen_sector = target.disk_controller == Target::DiskController::SixteenSector;
 			if(has_disk_controller) {
-				// Apple recommended slot 6 for the (first) Disk II.
 				request = request && DiskIICard::rom_request(is_sixteen_sector);
 			}
 
+			// Add a SCSI card if requested.
+			const bool has_scsi_card = true;	// TODO: obtain via the target.
+			if(has_scsi_card) {
+				request = request && SCSICard::rom_request();
+			}
+
 			// Request, validate and install ROMs.
 			auto roms = rom_fetcher(request);
 			if(!request.validate(roms)) {
@@ -471,9 +477,15 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			}
 
 			if(has_disk_controller) {
+				// Apple recommended slot 6 for the (first) Disk II.
 				install_card(6, new Apple::II::DiskIICard(roms, is_sixteen_sector));
 			}
 
+			if(has_scsi_card) {
+				// Install the SCSI card in slot 7, to one-up any connected Disk II.
+				install_card(7, new Apple::II::SCSICard(roms));
+			}
+
 			rom_ = std::move(roms.find(system)->second);
 			// The IIe and Enhanced IIe ROMs often distributed are oversized; trim if necessary.
 			if(system == ROM::Name::AppleIIe || system == ROM::Name::AppleIIEnhancedE) {

Machines/Apple/AppleII/Card.hpp

@@ -42,9 +42,9 @@ class Card {
 	public:
 		virtual ~Card() {}
 		enum Select: int {
-			None	= 0,		// No select line is active
-			IO		= 1 << 0,	// IO select is active
-			Device	= 1 << 1,	// Device select is active
+			None	= 0,		// No select line is active.
+			IO		= 1 << 0,	// IO select is active; i.e. access is in range $C0x0 to $C0xf.
+			Device	= 1 << 1,	// Device select is active; i.e. access is in range $Cx00 to $Cxff.
 		};
 
 		/*!

Machines/Apple/AppleII/SCSICard.cpp

@@ -8,8 +8,6 @@
 
 #include "SCSICard.hpp"
 
-#include "../../../Components/5380/ncr5380.hpp"
-
 // Per the documentation around the GGLabs Apple II SCSI card clone:
 //
 // A 5380 is mapped to the first eight bytes of slot IO:
@@ -50,3 +48,57 @@
 //	at $CC00-$CFFF. The boot code in the first 256 bytes of ROM
 //	bank 0 is also mapped in the IOSEL space ($Cn00-$CnFF).
 //
+
+using namespace Apple::II;
+
+ROM::Request SCSICard::rom_request() {
+	return ROM::Request(ROM::Name::AppleIISCSICard);
+}
+
+// TODO: accept and supply real clock rate.
+SCSICard::SCSICard(ROM::Map &map) : scsi_bus_(1), ncr5380_(scsi_bus_, 1) {
+	// Grab a copy of the SCSI ROM.
+	const auto rom = map.find(ROM::Name::AppleIISCSICard);
+	if(rom == map.end()) {
+		throw ROMMachine::Error::MissingROMs;
+	}
+	memcpy(rom_.data(), rom->second.data(), rom_.size());
+
+	// Set up initial banking.
+	rom_pointer_ = rom_.data();
+	ram_pointer_ = ram_.data();
+}
+
+void SCSICard::perform_bus_operation(Select select, bool is_read, uint16_t address, uint8_t *value) {
+	// TODO.
+	switch(select) {
+		case Select::None:
+		break;
+
+		case Select::Device:
+			if(is_read) {
+				*value = rom_[address & 255];
+			}
+		break;
+
+		case Select::IO:
+			address &= 0xf;
+			switch(address) {
+				case 0:	case 1:	case 2:	case 3:
+				case 4:	case 5:	case 6:	case 7:
+					if(is_read) {
+						*value = ncr5380_.read(address);
+					} else {
+						ncr5380_.write(address, *value);
+					}
+				break;
+
+				default:
+					printf("Unhandled: %04x %c %02x\n", address, is_read ? 'r' : 'w', *value);
+				break;
+			}
+		break;
+	}
+
+	// TODO: is it extra-contractual to respond in 0xc800 to 0xd000? Clarify.
+}

Machines/Apple/AppleII/SCSICard.hpp

@@ -12,6 +12,10 @@
 #include "Card.hpp"
 #include "../../ROMMachine.hpp"
 
+#include "../../../Components/5380/ncr5380.hpp"
+
+#include <array>
+
 namespace Apple {
 namespace II {
 
@@ -21,10 +25,18 @@ class SCSICard: public Card {
 		SCSICard(ROM::Map &);
 
 		void perform_bus_operation(Select select, bool is_read, uint16_t address, uint8_t *value) final;
-		void run_for(Cycles cycles, int stretches) final;
 
 	private:
-		// TODO.
+		uint8_t *ram_pointer_ = nullptr;
+		uint8_t *rom_pointer_ = nullptr;
+
+		std::array<uint8_t, 8*1024> ram_;
+		std::array<uint8_t, 16*1024> rom_;
+
+		SCSI::Bus scsi_bus_;
+		NCR::NCR5380::NCR5380 ncr5380_;
+
+		// TODO: the rest of this.
 };
 
 }