mirror of
https://github.com/JorjBauer/aiie.git
synced 2024-09-11 01:56:59 +00:00
542 lines
13 KiB
C++
542 lines
13 KiB
C++
#include "diskii.h"
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#ifdef TEENSYDUINO
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#include <Arduino.h>
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#else
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#endif
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#include "applemmu.h" // for FLOATING
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#include "globals.h"
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#include "diskii-rom.h"
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DiskII::DiskII(AppleMMU *mmu)
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{
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this->trackBuffer = new RingBuffer(NIBTRACKSIZE);
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this->rawTrackBuffer = (uint8_t *)malloc(4096);
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this->mmu = mmu;
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trackPos[0] = trackPos[1] = 0;
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prevTrack[0] = prevTrack[1] = 0;
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stepperPhases[0] = stepperPhases[1] = 0;
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curPhase[0] = curPhase[1] = 0;
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curTrack[0] = curTrack[1] = 0;
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trackDirty = false;
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trackToRead = -1;
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trackToFlush = -1;
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writeMode = false;
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writeProt = false; // FIXME: expose an interface to this
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readWriteLatch = 0x00;
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disk[0] = disk[1] = -1;
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indicatorIsOn[0] = indicatorIsOn[1] = 0;
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selectedDisk = 0;
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diskType[0] = diskType[1] = dosDisk;
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}
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DiskII::~DiskII()
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{
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delete this->trackBuffer; this->trackBuffer = NULL;
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free(this->rawTrackBuffer); this->rawTrackBuffer = NULL;
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}
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void DiskII::Reset()
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{
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trackPos[0] = trackPos[1] = 0;
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prevTrack[0] = prevTrack[1] = 0;
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stepperPhases[0] = stepperPhases[1] = 0;
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curPhase[0] = curPhase[1] = 0;
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curTrack[0] = curTrack[1] = 0;
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trackDirty = false;
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trackToRead = -1;
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trackToFlush = -1;
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writeMode = false;
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writeProt = false; // FIXME: expose an interface to this
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readWriteLatch = 0x00;
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ejectDisk(0);
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ejectDisk(1);
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}
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void DiskII::checkFlush(int8_t track)
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{
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if (trackDirty && trackToFlush == -1) {
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diskToFlush = selectedDisk;
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trackToFlush = track;
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trackDirty = false; // just so we don't overwrite disk/track to flush before continuing...
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}
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}
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uint8_t DiskII::readSwitches(uint8_t s)
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{
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switch (s) {
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case 0x00: // change stepper motor phase
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case 0x01:
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case 0x02:
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case 0x03:
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case 0x04:
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case 0x05:
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case 0x06:
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case 0x07:
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step(s);
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break;
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case 0x08: // drive off
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indicatorIsOn[selectedDisk] = 99;
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g_display->setDriveIndicator(selectedDisk, false); // FIXME: after a spell...
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checkFlush(curTrack[selectedDisk]);
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break;
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case 0x09: // drive on
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indicatorIsOn[selectedDisk] = 100;
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g_display->setDriveIndicator(selectedDisk, true);
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break;
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case 0x0A: // select drive 1
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select(0);
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break;
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case 0x0B: // select drive 2
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select(1);
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break;
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case 0x0C: // shift one read or write byte
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readWriteLatch = readOrWriteByte();
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break;
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case 0x0D: // load data register (latch)
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// This is complex and incomplete. cf. Logic State Sequencer,
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// UTA2E, p. 9-14
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if (!writeMode && indicatorIsOn[selectedDisk]) {
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if (isWriteProtected())
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readWriteLatch |= 0x80;
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else
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readWriteLatch &= 0x7F;
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}
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break;
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case 0x0E: // set read mode
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setWriteMode(false);
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// FIXME: with this shortcut here, disk access speeds up ridiculously.
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// Is this breaking anything?
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return ( (readOrWriteByte() & 0x7F) |
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(isWriteProtected() ? 0x80 : 0x00) );
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break;
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case 0x0F: // set write mode
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setWriteMode(true);
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break;
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}
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// FIXME: improve the spin-down here. We need a CPU cycle callback
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// for some period of time instead of this silly decrement counter.
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if (!indicatorIsOn[selectedDisk]) {
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// printf("Unexpected read while disk isn't on?\n");
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indicatorIsOn[selectedDisk] = 100;
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g_display->setDriveIndicator(selectedDisk, true);
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}
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if (indicatorIsOn[selectedDisk] > 0 && indicatorIsOn[selectedDisk] < 100) {
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// slowly spin it down...
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if (--indicatorIsOn[selectedDisk] == 0) {
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g_display->setDriveIndicator(selectedDisk, false);
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}
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}
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// Any even address read returns the readWriteLatch (UTA2E Table 9.1,
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// p. 9-12, note 2)
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return (s & 1) ? FLOATING : readWriteLatch;
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}
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void DiskII::writeSwitches(uint8_t s, uint8_t v)
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{
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switch (s) {
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case 0x00: // change stepper motor phase
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case 0x01:
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case 0x02:
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case 0x03:
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case 0x04:
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case 0x05:
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case 0x06:
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case 0x07:
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step(s);
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break;
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case 0x08: // drive off
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break;
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case 0x09: // drive on
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break;
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case 0x0A: // select drive 1
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select(0);
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break;
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case 0x0B: // select drive 2
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select(1);
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break;
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case 0x0C: // shift one read or write byte
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readOrWriteByte();
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break;
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case 0x0D: // drive write
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break;
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case 0x0E: // set read mode
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setWriteMode(false);
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break;
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case 0x0F: // set write mode
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setWriteMode(true);
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break;
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}
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// All writes update the latch
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if (writeMode) {
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readWriteLatch = v;
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}
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}
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// where a is the address poked & 0x07 (e.g. "0xC0E0 & 0x07")
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void DiskII::step(uint8_t a)
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{
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int phase = (a >> 1) & 3;
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int phase_bit = (1 << phase);
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if (a & 1) {
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stepperPhases[selectedDisk] |= phase_bit;
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} else {
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stepperPhases[selectedDisk] &= ~phase_bit;
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}
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// If the magnet opposite the cog is off, then try to move. Move in
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// the direction of adjacent magent - but if both adjacent magents
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// are on, then don't move at all.
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int direction = 0;
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int cur_phase = curPhase[selectedDisk];
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if (stepperPhases[selectedDisk] & (1 << ((cur_phase + 1) & 3))) {
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direction++;
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}
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if (stepperPhases[selectedDisk] & (1 << ((cur_phase+3) & 3))) {
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direction--;
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}
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if (direction) {
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int next_phase = cur_phase + direction;
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if (next_phase < 0) {
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next_phase = 0;
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// recalibrate
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}
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// FIXME: don't go beyond the end of the media. For a 35-track disk, that's 68 == ((35-1) * 2).
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if (next_phase > 69) {
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next_phase = 69;
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// ... Or go to 79? or 68, which we stopped at before? Not sure
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// what the right behavior is here.
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}
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if ((cur_phase >> 1) != (next_phase >> 1)) {
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// We're about to change tracks - be sure to flush the track if we've written to it
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checkFlush(prevTrack[selectedDisk]);
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prevTrack[selectedDisk] = curTrack[selectedDisk];
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curTrack[selectedDisk] = next_phase>>1;
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// mark it to be read
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trackToRead = curTrack[selectedDisk];
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}
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curPhase[selectedDisk] = next_phase;
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}
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}
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bool DiskII::isWriteProtected()
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{
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return (writeProt ? 0xFF : 0x00);
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}
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void DiskII::setWriteMode(bool enable)
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{
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writeMode = enable;
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}
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static uint8_t _lc(char c)
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{
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if (c >= 'A' && c <= 'Z') {
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c = c - 'A' + 'a';
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}
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return c;
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}
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static bool _endsWithI(const char *s1, const char *s2)
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{
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if (strlen(s2) > strlen(s1)) {
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return false;
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}
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const char *p = &s1[strlen(s1)-1];
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int16_t l = strlen(s2)-1;
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while (l >= 0) {
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if (_lc(*p--) != _lc(s2[l]))
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return false;
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l--;
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}
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return true;
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}
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void DiskII::insertDisk(int8_t driveNum, const char *filename, bool drawIt)
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{
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ejectDisk(driveNum);
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disk[driveNum] = g_filemanager->openFile(filename);
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if (drawIt)
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g_display->drawDriveDoor(driveNum, false);
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if (_endsWithI(filename, ".nib")) {
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diskType[driveNum] = nibDisk;
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} else if (_endsWithI(filename, ".po")) {
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diskType[driveNum] = prodosDisk;
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} else {
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diskType[driveNum] = dosDisk;
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#ifndef TEENSYDUINO
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// debugging: make a nib copy of the image to play with
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// convertDskToNib("/tmp/debug.nib");
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#endif
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}
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}
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void DiskII::ejectDisk(int8_t driveNum)
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{
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if (disk[driveNum] != -1) {
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g_filemanager->closeFile(disk[driveNum]);
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disk[driveNum] = -1;
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g_display->drawDriveDoor(driveNum, true);
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}
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}
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void DiskII::select(int8_t which)
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{
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if (which != 0 && which != 1)
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return;
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if (which != selectedDisk) {
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indicatorIsOn[selectedDisk] = 0;
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g_display->setDriveIndicator(selectedDisk, false);
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checkFlush(curTrack[selectedDisk]);
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}
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// set the selected disk drive
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selectedDisk = which;
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trackToRead = curTrack[selectedDisk];
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}
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uint8_t DiskII::readOrWriteByte()
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{
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if (disk[selectedDisk] == -1) {
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return GAP;
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}
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if (writeMode && !writeProt) {
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if (!trackBuffer->hasData()) {
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// Error: writing to empty track buffer? That's a raw write w/o
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// knowing where we are on the disk.
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return GAP;
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}
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trackDirty = true;
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// It's possible that a badly behaving OS could try to write more
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// data than we have buffer to handle. Don't let it. We should
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// only need something like 500 bytes, at worst. In the typical
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// case, we're talking about something like
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//
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// ~5 bytes of GAP
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// 3 bytes of sector prolog
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// 2 bytes of volume
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// 2 bytes of track
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// 2 bytes of sector
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// 2 bytes of checksum
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// 2 bytes of epilog
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// ~5 bytes of GAP
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// 3 bytes of data prolog
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// 342 bytes of GRP-encoded (6:2) data
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// 1 byte of checksum
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// 3 bytes of epilog
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// 1 byte of GAP
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// == 373 bytes
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//
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// ... so if we get up to the full 1024 we've allocated, there's
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// something suspicious happening.
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if (readWriteLatch < 0x96) {
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// Can't write a de-nibblized byte...
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g_display->debugMsg("DII: bad write");
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return 0;
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}
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trackBuffer->replaceByte(readWriteLatch);
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return 0;
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}
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// trackToRead is -1 when we have a filled buffer, or we have no data at all.
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// trackToRead is != -1 when we're flushing our buffer and re-filling it.
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//
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// Don't fill it right here, b/c we don't want to bog down the CPU
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// thread/ISR.
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if (trackToRead == curTrack[selectedDisk]) {// waiting for a read to complete
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return GAP;
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}
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if ((trackToRead != -1) || !trackBuffer->hasData()) {
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checkFlush(curTrack[selectedDisk]);
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// Need to read in a track of data and nibblize it. We'll return 0xFF
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// until that completes.
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// This might update trackToRead with a different track than the
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// one we're reading. When we finish the read, we'll need to check
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// to be sure that we're still trying to read the same track that
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// we started with.
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trackToRead = curTrack[selectedDisk];
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// While we're waiting for the sector to come around, we'll return
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// GAP bytes.
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return GAP;
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}
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return trackBuffer->peekNext();
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}
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void DiskII::fillDiskBuffer()
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{
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if (trackToFlush != -1) {
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flushTrack(trackToFlush, diskToFlush); // in case it's dirty: flush before changing drives
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trackBuffer->clear();
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trackToFlush = -1;
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}
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// No work to do if trackToRead is -1
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if (trackToRead == -1)
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return;
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trackDirty = false;
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trackBuffer->clear();
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int8_t trackWeAreReading = trackToRead;
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int8_t diskWeAreUsing = selectedDisk;
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trackBuffer->clear();
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trackBuffer->setPeekCursor(0);
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if (diskType[diskWeAreUsing] == nibDisk) {
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// Read one nibblized sector at a time and jam it in trackBuf
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// directly. We don't read the whole track at once only because
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// of RAM constraints on the Teensy. There's no reason we
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// couldn't, though, if RAM weren't at a premium.
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for (int i=0; i<16; i++) {
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g_filemanager->seekBlock(disk[diskWeAreUsing], trackWeAreReading * 16 + i, diskType[diskWeAreUsing] == nibDisk);
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if (!g_filemanager->readBlock(disk[diskWeAreUsing], rawTrackBuffer, diskType[diskWeAreUsing] == nibDisk)) {
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// FIXME: error handling?
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trackToRead = -1;
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return;
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}
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trackBuffer->addBytes(rawTrackBuffer, 416);
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}
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} else {
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// It's a .dsk / .po disk image. Read the whole track in to
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// rawTrackBuffer and nibblize it.
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g_filemanager->seekBlock(disk[diskWeAreUsing], trackWeAreReading * 16, diskType[diskWeAreUsing] == nibDisk);
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if (!g_filemanager->readTrack(disk[diskWeAreUsing], rawTrackBuffer, diskType[diskWeAreUsing] == nibDisk)) {
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// FIXME: error handling?
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trackToRead = -1;
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return;
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}
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nibblizeTrack(trackBuffer, rawTrackBuffer, diskType[diskWeAreUsing], curTrack[selectedDisk]);
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}
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// Make sure we're still intending to read the track we just read
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if (trackWeAreReading != trackToRead ||
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diskWeAreUsing != selectedDisk) {
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// Abort and let it start over next time
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return;
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}
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// Buffer is full, we're done - reset trackToRead and that will let the reads reach the CPU!
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trackToRead = -1;
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}
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const char *DiskII::DiskName(int8_t num)
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{
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if (disk[num] != -1)
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return g_filemanager->fileName(disk[num]);
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return "";
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}
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void DiskII::loadROM(uint8_t *toWhere)
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{
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#ifdef TEENSYDUINO
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Serial.println("loading DiskII rom");
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for (uint16_t i=0; i<=0xFF; i++) {
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toWhere[i] = pgm_read_byte(&romData[i]);
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}
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#else
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printf("loading DiskII rom\n");
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memcpy(toWhere, romData, 256);
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#endif
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}
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void DiskII::flushTrack(int8_t track, int8_t sel)
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{
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// safety check: if we're write-protected, then how did we get here?
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if (writeProt) {
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g_display->debugMsg("Write Protected");
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return;
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}
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if (!trackBuffer->hasData()) {
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// Dunno what happened - we're writing but haven't initialized the sector buffer?
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return;
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}
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if (diskType[sel] == nibDisk) {
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// Write the whole track out exactly as we've got it. Hopefully
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// someone has re-calcuated appropriate checksums on it...
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g_display->debugMsg("Not writing Nib image");
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return;
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}
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nibErr e = denibblizeTrack(trackBuffer, rawTrackBuffer, diskType[sel], curTrack[selectedDisk]);
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switch (e) {
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case errorShortTrack:
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g_display->debugMsg("DII: short track");
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trackBuffer->clear();
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return;
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case errorMissingSectors:
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g_display->debugMsg("DII: missing sectors");
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trackBuffer->clear();
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break;
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case errorNone:
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break;
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}
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// ok, write the track!
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g_filemanager->seekBlock(disk[sel], track * 16);
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g_filemanager->writeTrack(disk[sel], rawTrackBuffer);
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}
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