From 523b9c4a032b9a72a267cef253d622600570de1c Mon Sep 17 00:00:00 2001
From: Peter Evans <peter@modul8r.com>
Date: Fri, 30 Mar 2018 16:07:58 -0500
Subject: [PATCH] Several changes...

1. We have much more logging.
2. We were not properly turning off drives when we would get called with
   C0x8.
3. We now roll over sector pos if we are greater than ENC_ETRACK.
4. We now reset sector pos when we step.
---
 src/apple2.dd.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/apple2.dd.c b/src/apple2.dd.c
index d138f13..07d40fc 100644
--- a/src/apple2.dd.c
+++ b/src/apple2.dd.c
@@ -281,6 +281,10 @@ apple2_dd_phaser(apple2dd *drive, int phase)
     int step = transitions[(drive->phase * 5) + phase];
     apple2_dd_step(drive, step);
 
+    log_info("Phase %1d, step %2d, track %2d, sector pos %05x, segment position %05x",
+             phase, step, drive->track_pos / 2, drive->sector_pos,
+             apple2_dd_position(drive));
+
     // Record this new phase for the next time we make a transition
     drive->phase = phase;
 }
@@ -316,6 +320,12 @@ apple2_dd_read(apple2dd *drive)
     }
 
     vm_8bit byte = vm_segment_get(drive->data, apple2_dd_position(drive));
+    drive->latch = byte;
+
+    log_info("Read byte %02x at track %2d, sector %2d, position %05x",
+             byte, drive->track_pos / 2, drive->sector_pos / ENC_ESECTOR,
+             apple2_dd_position(drive));
+
     apple2_dd_shift(drive, 1);
 
     return byte;
@@ -385,7 +395,7 @@ apple2_dd_shift(apple2dd *drive, int pos)
 
     drive->sector_pos += pos;
 
-    if (drive->sector_pos >= ENC_ETRACK) {
+    if (drive->sector_pos > ENC_ETRACK) {
         // We need to reset the sector pos to zero, because...
         drive->sector_pos = 0;
     }
@@ -408,6 +418,8 @@ apple2_dd_step(apple2dd *drive, int steps)
     } else if (drive->track_pos < 0) {
         drive->track_pos = 0;
     }
+
+    drive->sector_pos = 0;
 }
 
 /*
@@ -466,6 +478,10 @@ apple2_dd_switch_phase(apple2dd *drive, size_t addr)
         case 0x7: phase = 4; break;
     }
 
+    if (phase == -1) {
+        log_info("Phase addr %02x, operation skipped", addr & 0xf);
+    }
+
     apple2_dd_phaser(drive, phase);
 }
 
@@ -579,7 +595,7 @@ SEGMENT_READER(apple2_dd_switch_read)
     
     // In the first if block, we will handle 0x0..0x8; in the second if,
     // we'll do 0x9..0xB, 0xE, and 0xF.
-    if (nib < 0x9) {
+    if (nib < 0x8) {
         apple2_dd_switch_phase(drive, nib);
     } else if (nib < 0xC || nib > 0xD) {
         apple2_dd_switch_drive(mach, nib);
@@ -617,7 +633,7 @@ SEGMENT_WRITER(apple2_dd_switch_write)
         drive = mach->drive1;
     }
     
-    if (nib < 0x9) {
+    if (nib < 0x8) {
         apple2_dd_switch_phase(drive, nib);
     } else if (nib < 0xC || nib > 0xD) {
         apple2_dd_switch_drive(mach, nib);