From b7065575f3b23d0c15bcebba1025cde52ff3910c Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 14 Aug 2017 09:04:22 -0400
Subject: [PATCH] Added (empty) call-ins for DMA usage; switched to having the
 'is seeking' bit in the status register stay high until sense interrupt
 status, but now it goes high even for seeks that don't actually go anywhere,
 and corrected interpretation of the specify command, with a positive result:
 the received step rate time, now that it's being interpreted correctly, is
 much shorter.

---
 Components/8272/i8272.cpp | 24 +++++++++++++++---------
 Components/8272/i8272.hpp |  4 +++-
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/Components/8272/i8272.cpp b/Components/8272/i8272.cpp
index 194b8595b..a7d1f0754 100644
--- a/Components/8272/i8272.cpp
+++ b/Components/8272/i8272.cpp
@@ -93,7 +93,6 @@ void i8272::run_for(Cycles cycles) {
 					// Check for completion.
 					if(drives_[c].seek_is_satisfied()) {
 						drives_[c].phase = Drive::CompletedSeeking;
-						main_status_ &= ~(1 << c);
 						if(drives_[c].target_head_position == -1) drives_[c].head_position = 0;
 						break;
 					}
@@ -658,13 +657,12 @@ void i8272::posit_event(int event_type) {
 				drives_[drive].target_head_position = (command_.size() > 2) ? command_[2] : -1;
 				drives_[drive].step_rate_counter = 0;
 				drives_[drive].seek_failed = false;
+				main_status_ |= 1 << (command_[1]&3);
 				printf("Accepted seek to %d\n", drives_[drive].target_head_position);
 
 				// Check whether any steps are even needed.
 				if(drives_[drive].seek_is_satisfied()) {
 					drives_[drive].phase = Drive::CompletedSeeking;
-				} else {
-					main_status_ |= 1 << (command_[1]&3);
 				}
 			} else {
 				printf("Rejected seek to %d\n", (command_.size() > 2) ? command_[2] : -1);
@@ -688,6 +686,7 @@ void i8272::posit_event(int event_type) {
 				if(found_drive != -1) {
 					drives_[found_drive].phase = Drive::NotSeeking;
 					status_[0] = (uint8_t)found_drive;
+					main_status_ &= ~(1 << found_drive);
 					SetSeekEnd();
 
 					result_stack_.push_back(drives_[found_drive].head_position);
@@ -702,17 +701,17 @@ void i8272::posit_event(int event_type) {
 	specify:
 		// Just store the values, and terminate the command.
 			printf("Specify\n");
-			step_rate_time_ = command_[1] &0xf0;		// i.e. 16 to 240m
-			head_unload_time_ = command_[1] & 0x0f;		// i.e. 1 to 16ms
-			head_load_time_ = command_[2] & ~1;			// i.e. 2 to 254 ms in increments of 2ms
+			step_rate_time_ = 16 - (command_[1] >> 4);			// i.e. 1 to 16ms
+			head_unload_time_ = (command_[1] & 0x0f) << 4;		// i.e. 16 to 240ms
+			head_load_time_ = command_[2] & ~1;					// i.e. 2 to 254 ms in increments of 2ms
 
-			if(!step_rate_time_) step_rate_time_ = 16;
-			if(!head_unload_time_) head_unload_time_ = 1;
+			if(!head_unload_time_) head_unload_time_ = 16;
 			if(!head_load_time_) head_load_time_ = 2;
 			dma_mode_ = !(command_[2] & 1);
 			goto wait_for_command;
 
 	sense_drive_status:
+			printf("Sense drive status\n");
 			{
 				int drive = command_[1] & 3;
 				result_stack_.push_back(
@@ -749,7 +748,7 @@ void i8272::posit_event(int event_type) {
 	// Posts whatever is in result_stack_ as a result phase. Be aware that it is a stack — the
 	// last thing in it will be returned first.
 	post_result:
-			printf("Result: ");
+			printf("Result to %02x: ", command_[0] & 0x1f);
 			for(size_t c = 0; c < result_stack_.size(); c++) {
 				printf("%02x ", result_stack_[result_stack_.size() - 1 - c]);
 			}
@@ -780,3 +779,10 @@ void i8272::set_dma_acknowledge(bool dack) {
 
 void i8272::set_terminal_count(bool tc) {
 }
+
+void i8272::set_data_input(uint8_t value) {
+}
+
+uint8_t i8272::get_data_output() {
+	return 0xff;
+}
diff --git a/Components/8272/i8272.hpp b/Components/8272/i8272.hpp
index 26766abd3..a0734cb05 100644
--- a/Components/8272/i8272.hpp
+++ b/Components/8272/i8272.hpp
@@ -31,6 +31,9 @@ class i8272: public Storage::Disk::MFMController {
 
 		void run_for(Cycles);
 
+		void set_data_input(uint8_t value);
+		uint8_t get_data_output();
+
 		void set_register(int address, uint8_t value);
 		uint8_t get_register(int address);
 
@@ -40,7 +43,6 @@ class i8272: public Storage::Disk::MFMController {
 		void set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive);
 
 	private:
-
 		// The bus handler, for interrupt and DMA-driven usage.
 		BusHandler &bus_handler_;
 		std::unique_ptr<BusHandler> allocated_bus_handler_;