Attempt proper EOP semantics; multisector reads.

Machines/PCCompatible/DMA.hpp

@@ -15,6 +15,12 @@
 
 namespace PCCompatible {
 
+enum class AccessResult {
+	Accepted,
+	AcceptedWithEOP,
+	NotAccepted,
+};
+
 class i8237 {
 	public:
 		void flip_flop_reset() {
@@ -149,32 +155,38 @@ class i8237 {
 		//
 		// Interface for reading/writing via DMA.
 		//
-		static constexpr auto NotAvailable = uint32_t(~0);
 
 		/// Provides the next target address for @c channel if performing either a write (if @c is_write is @c true) or read (otherwise).
 		///
-		/// @returns Either a 16-bit address or @c NotAvailable if the requested channel isn't set up to perform a read or write at present.
+		/// @returns A combined address and @c AccessResult.
-		uint32_t access(size_t channel, bool is_write) {
+		std::pair<uint16_t, AccessResult> access(size_t channel, bool is_write) {
-//			if(channels_[channel].transfer_complete) {
-//				return NotAvailable;
-//			}
 			if(is_write && channels_[channel].transfer != Channel::Transfer::Write) {
-				return NotAvailable;
+				return std::make_pair(0, AccessResult::NotAccepted);
 			}
 			if(!is_write && channels_[channel].transfer != Channel::Transfer::Read) {
-				return NotAvailable;
+				return std::make_pair(0, AccessResult::NotAccepted);
 			}
 
 			const auto address = channels_[channel].address.full;
 			channels_[channel].address.full += channels_[channel].address_decrement ? -1 : 1;
 
 			--channels_[channel].count.full;
+
+			const bool was_complete = channels_[channel].transfer_complete;
 			channels_[channel].transfer_complete = (channels_[channel].count.full == 0xffff);
 			if(channels_[channel].transfer_complete) {
 				// TODO: _something_ with mode.
 			}
 
-			return address;
+			auto result = AccessResult::Accepted;
+			if(!was_complete && channels_[channel].transfer_complete) {
+				result = AccessResult::AcceptedWithEOP;
+			}
+			return std::make_pair(address, result);
+		}
+
+		void set_complete(size_t channel) {
+			channels_[channel].transfer_complete = true;
 		}
 
 	private:
@@ -257,16 +269,15 @@ class DMA {
 		}
 
 		// TODO: this permits only 8-bit DMA. Fix that.
-		bool write(size_t channel, uint8_t value) {
+		AccessResult write(size_t channel, uint8_t value) {
-			auto address = controller.access(channel, true);
+			auto access = controller.access(channel, true);
-			if(address == i8237::NotAvailable) {
+			if(access.second == AccessResult::NotAccepted) {
-				return false;
+				return access.second;
 			}
 
-			address |= uint32_t(pages.channel_page(channel) << 16);
+			const uint32_t address = uint32_t(pages.channel_page(channel) << 16) | access.first;
 			*memory_->at(address) = value;
-
+			return access.second;
-			return true;
 		}
 
 	private:

Machines/PCCompatible/PCCompatible.cpp

@@ -119,58 +119,75 @@ class FloppyController {
 						status_.begin(decoder_);
 
 						// Search for a matching sector.
-						const auto target = decoder_.geometry();
+						auto target = decoder_.geometry();
-						bool found_sector = false;
+//						bool found_sector = false;
-						for(auto &pair: drives_[decoder_.target().drive].sectors(decoder_.target().head)) {
-							if(
-								(pair.second.address.track == target.cylinder) &&
-								(pair.second.address.sector == target.sector) &&
-								(pair.second.address.side == target.head) &&
-								(pair.second.size == target.size)
-							) {
-								found_sector = true;
-								bool wrote_in_full = true;
 
-								printf("Writing data beginning: ");
+						bool complete = false;
-								for(int c = 0; c < 128 << target.size; c++) {
+						while(!complete) {
-									if(c < 8) printf("%02x ", pair.second.samples[0].data()[c]);
+							for(auto &pair: drives_[decoder_.target().drive].sectors(decoder_.target().head)) {
+								if(
+									(pair.second.address.track == target.cylinder) &&
+									(pair.second.address.sector == target.sector) &&
+									(pair.second.address.side == target.head) &&
+									(pair.second.size == target.size)
+								) {
+//									found_sector = true;
+//									bool wrote_in_full = true;
 
-									if(!dma_.write(2, pair.second.samples[0].data()[c])) {
+									printf("Writing data beginning: ");
-										printf("FDC: DMA not permitted\n");
+									for(int c = 0; c < 128 << target.size; c++) {
-										wrote_in_full = false;
+										if(c < 8) printf("%02x ", pair.second.samples[0].data()[c]);
-										break;
+
+										const auto access_result = dma_.write(2, pair.second.samples[0].data()[c]);
+										switch(access_result) {
+											default: break;
+											case AccessResult::NotAccepted:
+												printf("FDC: DMA not permitted\n");
+//												wrote_in_full = false;
+											break;
+											case AccessResult::AcceptedWithEOP:
+												complete = true;
+											break;
+										}
+										if(access_result != AccessResult::Accepted) {
+											break;
+										}
 									}
-								}
-								printf("\n");
 
-								if(wrote_in_full) {
+									++target.sector;	// TODO: multitrack?
-									results_.serialise(
+									printf("\n");
-										status_,
-										decoder_.geometry().cylinder,
-										decoder_.geometry().head,
-										decoder_.geometry().sector,
-										decoder_.geometry().size);
-								} else {
-									printf("FDC: didn't write in full\n");
-									// TODO: Overrun, presumably?
-								}
 
-								break;
+//									if(wrote_in_full) {
+//									} else {
+//										printf("FDC: didn't write in full\n");
+//										// TODO: Overrun, presumably?
+//									}
+
+									break;
+								}
 							}
 						}
 
-						if(!found_sector) {
+						results_.serialise(
-							printf("FDC: sector not found\n");
+							status_,
-							// TODO: there's more than this, I think.
+							decoder_.geometry().cylinder,
-							status_.set(Intel::i8272::Status0::AbnormalTermination);
+							decoder_.geometry().head,
-							results_.serialise(
+							decoder_.geometry().sector,
-								status_,
+							decoder_.geometry().size);
-								decoder_.geometry().cylinder,
-								decoder_.geometry().head,
-								decoder_.geometry().sector,
-								decoder_.geometry().size);
-						}
 
+//						if(!found_sector) {
+//							printf("FDC: sector not found\n");
+//							// TODO: there's more than this, I think.
+//							status_.set(Intel::i8272::Status0::AbnormalTermination);
+//							results_.serialise(
+//								status_,
+//								decoder_.geometry().cylinder,
+//								decoder_.geometry().head,
+//								decoder_.geometry().sector,
+//								decoder_.geometry().size);
+//						}
+
+						// TODO: what if head has changed?
 						drives_[decoder_.target().drive].status = decoder_.drive_head();
 						drives_[decoder_.target().drive].raised_interrupt = true;
 						pic_.apply_edge<6>(true);