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Made an attempt at some of the correct seek/recalibrate behaviour: it's now asynchronous from command processing and able to work on up to four drives at once. I just probably am not yet hitting all the status flags I need to hit.

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This commit is contained in:
Thomas Harte 2017-08-06 15:22:07 -04:00
parent a7103f9333
commit 6c5b562d97
2 changed files with 74 additions and 5 deletions
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61
Components/8272/i8272.cpp
View File

@ -27,12 +27,15 @@ i8272::i8272(Cycles clock_rate, int clock_rate_multiplier, int revolutions_per_m
main_status_(StatusRQM),
interesting_event_mask_((int)Event8272::CommandByte),
resume_point_(0),
delay_time_(0) {
delay_time_(0),
status_{0, 0, 0, 0} {
posit_event((int)Event8272::CommandByte);
}
void i8272::run_for(Cycles cycles) {
Storage::Disk::MFMController::run_for(cycles);
// check for an expired timer
if(delay_time_ > 0) {
if(cycles.as_int() >= delay_time_) {
delay_time_ = 0;
@ -41,6 +44,28 @@ void i8272::run_for(Cycles cycles) {
delay_time_ -= cycles.as_int();
}
}
// update seek status of any drives presently seeking
for(int c = 0; c < 4; c++) {
if(drives_[c].phase == Drive::Seeking) {
drives_[c].step_rate_counter += cycles.as_int();
int steps = drives_[c].step_rate_counter / (8000 * step_rate_time_);
drives_[c].step_rate_counter %= (8000 * step_rate_time_);
while(steps--) {
if(
(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;
main_status_ &= ~(1 << c);
} else {
int direction = (drives_[c].target_head_position < drives_[c].head_position) ? -1 : 1;
drives_[c].drive.step(direction);
drives_[c].head_position += direction;
}
}
}
}
}
void i8272::set_register(int address, uint8_t value) {
@ -70,6 +95,9 @@ uint8_t i8272::get_register(int address) {
}
void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
if(drive < 4 && drive >= 0) {
drives_[drive].drive.set_disk(disk);
}
}
#define BEGIN_SECTION() switch(resume_point_) { default:
@ -197,12 +225,32 @@ void i8272::posit_event(int type) {
goto wait_for_command;
recalibrate:
printf("Recalibrate unimplemented!!\n");
printf("Recalibrate\n");
drives_[command_[1]&3].phase = Drive::Seeking;
drives_[command_[1]&3].permitted_steps = 77;
drives_[command_[1]&3].target_head_position = -1;
drives_[command_[1]&3].step_rate_counter = 0;
main_status_ |= (1 << command_[1]&3);
goto wait_for_command;
sense_interrupt_status:
printf("Sense interrupt status\n");
result_.push_back(head_position_);
// Find the first drive that is in the CompletedSeeking state and return for that;
// if none has done so then return 0xff for the sake of returning something.
// TODO: verify that fallback.
{
int found_drive = -1;
for(int c = 0; c < 4; c++) {
if(drives_[c].phase == Drive::CompletedSeeking) {
found_drive = c;
break;
}
}
if(found_drive != -1) {
drives_[found_drive].phase = Drive::NotSeeking;
result_.push_back(drives_[found_drive].head_position);
}
}
result_.push_back(status_[0]);
goto post_result;
@ -220,7 +268,12 @@ void i8272::posit_event(int type) {
goto post_result;
seek:
printf("Seek unimplemented!!\n");
printf("Seek\n");
drives_[command_[1]&3].phase = Drive::Seeking;
drives_[command_[1]&3].permitted_steps = -1;
drives_[command_[1]&3].target_head_position = command_[2];
drives_[command_[1]&3].step_rate_counter = 0;
main_status_ |= (1 << command_[1]&3);
goto wait_for_command;
invalid:

18
Components/8272/i8272.hpp
View File

@ -10,6 +10,7 @@
#define i8272_hpp
#include "../../Storage/Disk/MFMDiskController.hpp"
#include "../../Storage/Disk/Drive.hpp"
#include <cstdint>
#include <vector>
@ -50,7 +51,22 @@ class i8272: public Storage::Disk::MFMController {
int head_load_time_;
bool dma_mode_;
uint8_t head_position_;
struct Drive {
uint8_t head_position;
enum Phase {
NotSeeking,
Seeking,
CompletedSeeking
} phase;
int step_rate_counter;
int permitted_steps;
int target_head_position; // either an actual number, or -1 to indicate to step until track zero
Storage::Disk::Drive drive;
Drive() : head_position(0), phase(NotSeeking) {};
} drives_[4];
};
}