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Sought more robustly (i.e. less repetitively) to handle dispatch, including cancelling seeks where appropriate.

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This commit is contained in:
Thomas Harte 2017-08-14 10:37:39 -04:00
parent 7264fbb3d2
commit cefec7a19f
2 changed files with 46 additions and 72 deletions
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117
Components/8272/i8272.cpp
View File

@ -88,14 +88,14 @@ void i8272::run_for(Cycles cycles) {
while(steps--) {
// Perform a step.
int direction = (drives_[c].target_head_position < drives_[c].head_position) ? -1 : 1;
printf("Target %d versus believed %d\n", drives_[c].target_head_position, drives_[c].head_position);
drives_[c].drive->step(direction);
drives_[c].head_position += direction;
if(drives_[c].target_head_position >= 0) drives_[c].head_position += direction;
// 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;
}
}
@ -190,19 +190,12 @@ void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
if(distance_into_section_ < 6) goto CONCAT(read_header, __LINE__); \
set_data_mode(Scanning);
#define CLEAR_STATUS() \
status_[0] = status_[1] = status_[2] = 0;
#define SET_DRIVE_HEAD_MFM() \
active_drive_ = command_[1]&3; \
active_head_ = (command_[1] >> 2)&1; \
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() \
@ -248,76 +241,59 @@ void i8272::posit_event(int event_type) {
WAIT_FOR_EVENT(Event8272::CommandByte)
SetBusy();
static const size_t required_lengths[32] = {
0, 0, 9, 3, 2, 9, 9, 2,
1, 9, 2, 9, 0, 6, 0, 3,
0, 9, 0, 0, 0, 0, 0, 0,
0, 9, 0, 0, 0, 9, 0, 0,
};
if(command_.size() < required_lengths[command_[0] & 0x1f]) goto wait_for_complete_command_sequence;
ResetDataRequest();
status_[0] = status_[1] = status_[2] = 0;
// If this is not clearly a command that's safe to carry out in parallel to a seek, end all seeks.
switch(command_[0] & 0x1f) {
case 0x03: // specify
case 0x04: // sense drive status
case 0x07: // recalibrate
case 0x08: // sense interrupt status
case 0x0f: // seek
break;
default:
for(int c = 0; c < 4; c++) {
if(drives_[c].phase == Drive::Seeking) {
drives_[c].phase = Drive::NotSeeking;
drives_seeking_--;
}
}
break;
}
// Jump to the proper place.
switch(command_[0] & 0x1f) {
case 0x06: // read data
case 0x0b: // read deleted data
if(command_.size() < 9) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto read_data;
case 0x05: // write data
case 0x09: // write deleted data
if(command_.size() < 9) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto write_data;
case 0x02: // read track
if(command_.size() < 9) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto read_track;
case 0x02: goto read_track;
case 0x0a: goto read_id;
case 0x0d: goto format_track;
case 0x11: goto scan_low;
case 0x19: goto scan_low_or_equal;
case 0x1d: goto scan_high_or_equal;
case 0x07: goto recalibrate;
case 0x08: goto sense_interrupt_status;
case 0x03: goto specify;
case 0x04: goto sense_drive_status;
case 0x0f: goto seek;
case 0x0a: // read ID
if(command_.size() < 2) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto read_id;
case 0x0d: // format track
if(command_.size() < 6) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto format_track;
case 0x11: // scan low
if(command_.size() < 9) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto scan_low;
case 0x19: // scan low or equal
if(command_.size() < 9) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto scan_low_or_equal;
case 0x1d: // scan high or equal
if(command_.size() < 9) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto scan_high_or_equal;
case 0x07: // recalibrate
if(command_.size() < 2) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto recalibrate;
case 0x08: // sense interrupt status
ResetDataRequest();
goto sense_interrupt_status;
case 0x03: // specify
if(command_.size() < 3) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto specify;
case 0x04: // sense drive status
if(command_.size() < 2) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto sense_drive_status;
case 0x0f: // seek
if(command_.size() < 3) goto wait_for_complete_command_sequence;
ResetDataRequest();
goto seek;
default: // invalid
ResetDataRequest();
goto invalid;
default: goto invalid;
}
// Decodes drive, head and density, loads the head, loads the internal cylinder, head, sector and size registers,
@ -329,7 +305,6 @@ void i8272::posit_event(int event_type) {
if(!dma_mode_) SetNonDMAExecution();
SET_DRIVE_HEAD_MFM();
LOAD_HEAD();
CLEAR_STATUS();
cylinder_ = command_[2];
head_ = command_[3];
sector_ = command_[4];
@ -513,7 +488,6 @@ void i8272::posit_event(int event_type) {
printf("Read ID\n");
SET_DRIVE_HEAD_MFM();
LOAD_HEAD();
CLEAR_STATUS();
// Sets a maximum index hole limit of 2 then waits either until it finds a header mark or sees too many index holes.
// If a header mark is found, reads in the following bytes that produce a header. Otherwise branches to data not found.
@ -539,7 +513,6 @@ void i8272::posit_event(int event_type) {
if(!dma_mode_) SetNonDMAExecution();
SET_DRIVE_HEAD_MFM();
LOAD_HEAD();
CLEAR_STATUS();
// Wait for the index hole.
WAIT_FOR_EVENT(Event::IndexHole);

1
Storage/Disk/Drive.cpp
View File

@ -34,6 +34,7 @@ bool Drive::get_is_track_zero() {
void Drive::step(int direction) {
head_position_ = std::max(head_position_ + direction, 0);
printf("Head -> %d\n", head_position_);
}
void Drive::set_head(unsigned int head) {