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swim3: emulate on-chip 1 us timer.

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This commit is contained in:
Maxim Poliakovski 2022-11-17 18:02:53 +01:00
parent a0dd1884b3
commit d96351763f
2 changed files with 58 additions and 11 deletions
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42
devices/floppy/swim3.cpp
View File

@ -80,6 +80,8 @@ uint8_t Swim3Ctrl::read(uint8_t reg_offset)
uint8_t status_addr, rddata_val, old_int_flags, old_error;
switch(reg_offset) {
case Swim3Reg::Timer:
return this->calc_timer_val();
case Swim3Reg::Error:
old_error = this->error;
this->error = 0;
@ -127,7 +129,7 @@ void Swim3Ctrl::write(uint8_t reg_offset, uint8_t value)
switch(reg_offset) {
case Swim3Reg::Timer:
LOG_F(INFO, "SWIM3: writing %d to the Timer register", value);
this->init_timer(value);
break;
case Swim3Reg::Param_Data:
this->pram = value;
@ -357,6 +359,44 @@ void Swim3Ctrl::stop_disk_access()
this->access_timer_id = 0;
}
void Swim3Ctrl::init_timer(const uint8_t start_val)
{
if (this->timer_val) {
LOG_F(WARNING, "SWIM3: attempt to re-arm the timer");
}
this->timer_val = start_val;
if (!this->timer_val) {
this->one_us_timer_start = 0;
return;
}
this->one_us_timer_start = TimerManager::get_instance()->current_time_ns();
this->one_us_timer_id = TimerManager::get_instance()->add_oneshot_timer(
this->timer_val * NS_PER_USEC,
[this]() {
this->timer_val = 0;
this->int_flags |= INT_TIMER_DONE;
update_irq();
}
);
}
uint8_t Swim3Ctrl::calc_timer_val()
{
if (!this->timer_val) {
return 0;
}
uint64_t time_now = TimerManager::get_instance()->current_time_ns();
uint64_t us_elapsed = (time_now - this->one_us_timer_start) / NS_PER_USEC;
if (us_elapsed > this->timer_val) {
return 0;
} else {
return (this->timer_val - us_elapsed) & 0xFFU;
}
}
// floppy disk formats properties for the cases
// where disk format needs to be specified manually
static const std::vector<std::string> FloppyFormats = {

27
devices/floppy/swim3.h
View File

@ -64,9 +64,10 @@ enum {
/** Interrupt flags. */
enum {
INT_STEP_DONE = 0x02,
INT_ID_READ = 0x04,
INT_SECT_DONE = 0x08,
INT_TIMER_DONE = 0x01,
INT_STEP_DONE = 0x02,
INT_ID_READ = 0x04,
INT_SECT_DONE = 0x08,
};
// SWIM3 internal states.
@ -96,19 +97,22 @@ public:
};
protected:
void update_irq();
void start_stepping();
void do_step();
void stop_stepping();
void start_disk_access();
void disk_access();
void stop_disk_access();
void update_irq();
void start_stepping();
void do_step();
void stop_stepping();
void start_disk_access();
void disk_access();
void stop_disk_access();
void init_timer(const uint8_t start_val);
uint8_t calc_timer_val();
private:
std::unique_ptr<MacSuperdrive::MacSuperDrive> int_drive;
DmaBidirChannel* dma_ch;
uint8_t timer_val = 0; // internal timer that decrements at a 1 us rate
uint8_t setup_reg;
uint8_t mode_reg;
uint8_t error;
@ -128,9 +132,12 @@ private:
uint8_t rd_line;
int cur_state;
int one_us_timer_id = 0;
int step_timer_id = 0;
int access_timer_id = 0;
uint64_t one_us_timer_start = 0;
// Interrupt related stuff
InterruptCtrl* int_ctrl = nullptr;
uint32_t irq_id = 0;