6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2025-03-13 18:31:04 +00:00
Code Issues Projects Releases Wiki Activity

Decided that if this is an [M]FM parsing function then it should be something more intelligent than a mere PLL record. Which I guess conveniently implies Oric DSK-esque behaviour. But properly defined, rather than very vaguely.

Browse Source
This commit is contained in:
Thomas Harte 2016-12-30 23:10:52 -05:00
parent 632b3c63b1
commit 1f625fad66
2 changed files with 44 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
Storage/Disk/Encodings/MFM.cpp
View File

@ -126,7 +126,8 @@ static uint8_t logarithmic_size_for_size(size_t size)
case 256: return 1;
case 512: return 2;
case 1024: return 3;
case 2048: return 4;
case 2048: return 4; std::vector<uint8_t> get_track(uint8_t track);
case 4196: return 5;
}
}
@ -287,10 +288,10 @@ std::shared_ptr<Storage::Encodings::MFM::Sector> Parser::get_sector(uint8_t trac
return get_sector(sector);
}
std::vector<uint8_t> Parser::get_track(uint8_t track, size_t &number_of_bits)
std::vector<uint8_t> Parser::get_track(uint8_t track)
{
seek_to_track(track);
return get_track(number_of_bits);
return get_track();
}
void Parser::process_input_bit(int value, unsigned int cycles_since_index_hole)
@ -321,16 +322,17 @@ uint8_t Parser::get_next_byte()
return byte;
}
std::vector<uint8_t> Parser::get_track(size_t &number_of_bits)
std::vector<uint8_t> Parser::get_track()
{
std::vector<uint8_t> result;
number_of_bits = 0;
size_t number_of_bits = 0;
bool is_clock = false;
// align to the first index hole
index_count_ = 0;
while(!index_count_) run_for_cycles(1);
// capture every bit until the next index hole
// capture every other bit until the next index hole
index_count_ = 0;
while(1)
{
@ -341,11 +343,35 @@ std::vector<uint8_t> Parser::get_track(size_t &number_of_bits)
// if that was the index hole then finish
if(index_count_) break;
// otherwise, add another bit to the collection
int bit = number_of_bits & 7;
if(!bit) result.push_back(0);
result[number_of_bits >> 3] |= (shift_register_&1) << (7 - bit);
number_of_bits++;
// otherwise, add another bit to the collection if it wasn't a clock
if(!is_clock)
{
int bit = number_of_bits & 7;
if(!bit) result.push_back(0);
result[number_of_bits >> 3] |= (shift_register_&1) << (7 - bit);
number_of_bits++;
}
is_clock ^= true;
// if a synchronisation is detected then align
uint16_t low_shift_register = (shift_register_&0xffff);
bool is_sync = false;
if(is_mfm_)
{
is_sync = (low_shift_register == MFMIndexSync) || (low_shift_register == MFMSync);
}
else
{
is_sync =
(low_shift_register == FMIndexAddressMark) ||
(low_shift_register == FMIDAddressMark) ||
(low_shift_register == FMDataAddressMark) ||
(low_shift_register == FMDeletedDataAddressMark);
}
if(is_sync)
{
if(number_of_bits) number_of_bits += 7 - (number_of_bits&7);
}
}
return result;

11
Storage/Disk/Encodings/MFM.hpp
View File

@ -76,11 +76,14 @@ class Parser: public Storage::Disk::Controller {
/*!
Attempts to read the track at @c track, starting from the index hole.
All PLL-recognised bits are returned, filling their respective bytes from MSB to LSB.
Decodes data bits only; clocks are omitted. Synchronisation values begin a new
byte. If a synchronisation value begins partway through a byte then
synchronisation-contributing bits will appear both in the preceding byte and
in the next.
@returns a vector of data found. Also sets @c number_of_bits to the bit count.
@returns a vector of data found.
*/
std::vector<uint8_t> get_track(uint8_t track, size_t &number_of_bits);
std::vector<uint8_t> get_track(uint8_t track);
private:
Parser(bool is_mfm);
@ -100,7 +103,7 @@ class Parser: public Storage::Disk::Controller {
std::shared_ptr<Storage::Encodings::MFM::Sector> get_next_sector();
std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t sector);
std::vector<uint8_t> get_track(size_t &number_of_bits);
std::vector<uint8_t> get_track();
};