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Edging towards implementing IWM write support, but mainly tidied up.

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This commit is contained in:
Thomas Harte
2019-07-11 21:42:34 -04:00
parent 6c2cc206a6
commit c8917e677b
4 changed files with 66 additions and 44 deletions
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Components/DiskII/MacintoshDoubleDensityDrive.cpp
+30 -33
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@@ -8,6 +8,14 @@
#include "MacintoshDoubleDensityDrive.hpp"
/*
Sources used pervasively:
http://members.iinet.net.au/~kalandi/apple/AUG/1991/11%20NOV.DEC/DISK.STUFF.html
Apple Guide to the Macintosh Family Hardware
Inside Macintosh III
*/
using namespace Apple::Macintosh;
DoubleDensityDrive::DoubleDensityDrive(int input_clock_rate, bool is_800k) :
@@ -65,27 +73,27 @@ void DoubleDensityDrive::set_control_lines(int lines) {
if((old_state ^ control_state_) & control_state_ & Line::LSTRB) {
switch(control_state_ & (Line::CA1 | Line::CA0 | Line::SEL)) {
default:
// LOG("Unhandled LSTRB");
break;
case 0:
// LOG("LSTRB Set stepping direction: " << int(state_ & CA2));
case 0: // Set step direction — CA2 set => step outward.
step_direction_ = (control_state_ & Line::CA2) ? -1 : 1;
break;
case Line::CA1:
// LOG("LSTRB Motor");
case Line::CA1: // Set drive motor — CA2 set => motor off.
set_motor_on(!(control_state_ & Line::CA2));
break;
case Line::CA0:
// LOG("LSTRB Step");
step(Storage::Disk::HeadPosition(step_direction_));
case Line::CA0: // Initiate a step, if CA2 is clear.
if(!(control_state_ & Line::CA2))
step(Storage::Disk::HeadPosition(step_direction_));
break;
case Line::CA1 | Line::CA0:
// LOG("LSTRB Eject disk");
set_disk(nullptr);
case Line::SEL: // Reset has-been-ejected flag (if CA2 is set?)
break;
case Line::CA1 | Line::CA0: // Eject the disk if CA2 is set.
if(control_state_ & Line::CA2)
set_disk(nullptr); // TODO: should probably trigger the disk has been ejected bit?
break;
}
}
@@ -94,75 +102,64 @@ void DoubleDensityDrive::set_control_lines(int lines) {
bool DoubleDensityDrive::read() {
switch(control_state_ & (CA2 | CA1 | CA0 | SEL)) {
default:
// LOG("unknown)");
return false;
// Possible other meanings:
// B = ready (0 = ready)
// C = disk switched?
//
// {CA1,CA0,SEL,CA2}
case 0: // Head step direction.
// (0 = inward)
// LOG("head step direction)");
return step_direction_ <= 0;
case SEL: // Disk in place.
// (0 = disk present)
// LOG("disk in place)");
return !has_disk();
case CA0: // Disk head step completed.
// (0 = still stepping)
// LOG("head stepping)");
return true; // TODO: stepping delay. But at the main Drive level.
case CA0|SEL: // Disk locked.
// (0 = write protected)
// LOG("disk locked)");
return !get_is_read_only();
case CA1: // Disk motor running.
// (0 = motor on)
// LOG("disk motor running)");
return !get_motor_on();
case CA1|SEL: // Head at track 0.
// (0 = at track 0)
// LOG("head at track 0)");
// "This bit becomes valid beginning 12 msec after the step that places the head at track 0."
return !get_is_track_zero();
case CA1|CA0: // Disk has been ejected.
// (0 = user has ejected disk)
return false;
case CA1|CA0|SEL: // Tachometer.
// (arbitrary)
return get_tachometer();
case CA2: // Read data, lower head.
// LOG("data, lower head)\n");
set_head(0);
return false;;
return false;
case CA2|SEL: // Read data, upper head.
// LOG("data, upper head)\n");
set_head(1);
return false;
case CA2|CA1: // Single- or double-sided drive.
// (0 = single sided)
// LOG("single- or double-sided drive)");
return get_head_count() != 1;
case CA2|CA1|CA0: // "Present/HD" (per the Mac Plus ROM)
// (0 = ??HD??)
// LOG("present/HD)");
//
// Alternative explanation: "Disk ready for reading?"
// (0 = ready)
return false;
case CA2|CA1|CA0|SEL: // Drive installed.
// (0 = present, 1 = missing)
// LOG("drive installed)");
//
// TODO: why do I need to return this the wrong way around for the Mac Plus?
return true;
}
}
void DoubleDensityDrive::write(bool value) {
}