From 1c9a744b019ba1dcef947a96de4433c73d00fa79 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 6 Aug 2017 18:06:20 -0400
Subject: [PATCH] Made an effort to start inspecting ID fields, at least.
 Discovered that my emulation has somehow stopped proceeding beyond sense
 interrupt status though. Fix one in that area: adjust ST0 just in time for
 the sense interrupt status response, as that'll need to specify the drive
 number properly.

---
 Components/8272/i8272.cpp | 23 ++++++++++++++++++++++-
 Components/8272/i8272.hpp |  3 +++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Components/8272/i8272.cpp b/Components/8272/i8272.cpp
index 6d5917cf4..e19a62011 100644
--- a/Components/8272/i8272.cpp
+++ b/Components/8272/i8272.cpp
@@ -56,7 +56,7 @@ void i8272::run_for(Cycles cycles) {
 					(drives_[c].target_head_position == (int)drives_[c].head_position) ||
 					(drives_[c].drive.get_is_track_zero() && drives_[c].target_head_position == -1)) {
 					drives_[c].phase = Drive::CompletedSeeking;
-					status_[0] = (uint8_t)c | 0x20;
+					if(drives_[c].target_head_position == -1) drives_[c].head_position = 0;
 					main_status_ &= ~(1 << c);
 				} else {
 					int direction = (drives_[c].target_head_position < drives_[c].head_position) ? -1 : 1;
@@ -105,6 +105,24 @@ void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
 
 #define WAIT_FOR_EVENT(mask)	resume_point_ = __LINE__; interesting_event_mask_ = (int)mask; return; case __LINE__:
 
+#define FIND_HEADER()	\
+	{	\
+		find_header: WAIT_FOR_EVENT(Event::Token); \
+		if(get_latest_token().type != Token::ID) goto find_header;	\
+	}
+	
+#define READ_HEADER()	\
+	distance_into_header_ = 0;	\
+	set_data_mode(Reading);	\
+	{	\
+		read_header: WAIT_FOR_EVENT(Event::Token); \
+		header_[distance_into_header_] = get_latest_token().byte_value;	\
+		distance_into_header_++; \
+		if(distance_into_header_ != 7) goto read_header;	\
+	}	\
+	set_data_mode(Scanning);
+
+
 void i8272::posit_event(int type) {
 	if(!(interesting_event_mask_ & type)) return;
 	interesting_event_mask_ &= ~type;
@@ -185,6 +203,8 @@ void i8272::posit_event(int type) {
 		}
 
 	read_data:
+		FIND_HEADER();
+		READ_HEADER();
 		printf("Read data unimplemented!!\n");
 		goto wait_for_command;
 
@@ -248,6 +268,7 @@ void i8272::posit_event(int type) {
 			if(found_drive != -1) {
 				drives_[found_drive].phase = Drive::NotSeeking;
 				result_.push_back(drives_[found_drive].head_position);
+				status_[0] = (uint8_t)found_drive | 0x20;
 				result_.push_back(status_[0]);
 			} else {
 				result_.push_back(0x80);
diff --git a/Components/8272/i8272.hpp b/Components/8272/i8272.hpp
index ad6e12e34..db97de013 100644
--- a/Components/8272/i8272.hpp
+++ b/Components/8272/i8272.hpp
@@ -67,6 +67,9 @@ class i8272: public Storage::Disk::MFMController {
 
 			Drive() : head_position(0), phase(NotSeeking) {};
 		} drives_[4];
+
+		uint8_t header_[6];
+		int distance_into_header_;
 };
 
 }