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Ensured data-accessing commands cancel seeks on their drives. Also introduced a count of drives currently seeking in order to make for a slightly better broad-phase test in run_for.

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This commit is contained in:
Thomas Harte 2017-08-14 09:45:39 -04:00
parent b7065575f3
commit 8a7b23dc9e
2 changed files with 32 additions and 13 deletions
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43
Components/8272/i8272.cpp
View File

@ -60,7 +60,8 @@ i8272::i8272(BusHandler &bus_handler, Cycles clock_rate, int clock_rate_multipli
resume_point_(0),
delay_time_(0),
head_timers_running_(0),
expects_input_(false) {
expects_input_(false),
drives_seeking_(0) {
posit_event((int)Event8272::CommandByte);
}
@ -78,7 +79,7 @@ void i8272::run_for(Cycles cycles) {
}
// update seek status of any drives presently seeking
if(main_status_ & 0xf) {
if(drives_seeking_) {
for(int c = 0; c < 4; c++) {
if(drives_[c].phase == Drive::Seeking) {
drives_[c].step_rate_counter += cycles.as_int();
@ -93,6 +94,7 @@ void i8272::run_for(Cycles cycles) {
// Check for completion.
if(drives_[c].seek_is_satisfied()) {
drives_[c].phase = Drive::CompletedSeeking;
drives_seeking_--;
if(drives_[c].target_head_position == -1) drives_[c].head_position = 0;
break;
}
@ -197,6 +199,10 @@ void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
set_drive(drives_[active_drive_].drive); \
drives_[active_drive_].drive->set_head((unsigned int)active_head_); \
set_is_double_density(command_[0] & 0x40); \
if(drives_[active_drive_].phase == Drive::Seeking) { \
drives_[active_drive_].phase = Drive::NotSeeking; \
drives_seeking_--; \
}\
invalidate_track();
#define LOAD_HEAD() \
@ -646,26 +652,37 @@ void i8272::posit_event(int event_type) {
seek:
printf((command_.size() > 2) ? "Seek\n" : "Recalibrate\n");
// Declines to act if a seek is already ongoing; otherwise resets all status registers, sets the drive
// into seeking mode, sets the drive's main status seeking bit, and sets the target head position: for
// a recalibrate the target is -1 and ::run_for knows that -1 means the terminal condition is the drive
// returning that its at track zero, and that it should reset the drive's current position once reached.
if(drives_[command_[1]&3].phase != Drive::Seeking) {
{
int drive = command_[1]&3;
// Increment the seeking count if this drive wasn't already seeking.
if(drives_[drive].phase != Drive::Seeking) {
drives_seeking_++;
}
// Set currently seeking, with a step to occur right now (yes, it sounds like jamming these
// in could damage your drive motor).
drives_[drive].phase = Drive::Seeking;
drives_[drive].step_rate_counter = 8000 * step_rate_time_;
drives_[drive].steps_taken = 0;
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 this is a seek, set the processor-supplied target location; otherwise it is a recalibrate,
// which means resetting the current state now but aiming to hit '-1' (which the stepping code
// up in run_for understands to mean 'keep going until track 0 is active').
if(command_.size() > 2) {
drives_[drive].target_head_position = command_[2];
} else {
drives_[drive].target_head_position = -1;
drives_[drive].head_position = 0;
}
// Check whether any steps are even needed; if not then mark as completed already.
if(drives_[drive].seek_is_satisfied()) {
drives_[drive].phase = Drive::CompletedSeeking;
drives_seeking_--;
}
} else {
printf("Rejected seek to %d\n", (command_.size() > 2) ? command_[2] : -1);
}
goto wait_for_command;

2
Components/8272/i8272.hpp
View File

@ -81,6 +81,7 @@ class i8272: public Storage::Disk::MFMController {
Seeking,
CompletedSeeking
} phase;
bool did_seek;
bool seek_failed;
// Seeking: transient state.
@ -103,6 +104,7 @@ class i8272: public Storage::Disk::MFMController {
drive(new Storage::Disk::Drive),
head_is_loaded{false, false} {};
} drives_[4];
int drives_seeking_;
// User-supplied parameters; as per the specify command.
int step_rate_time_;