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Fixed issue whereby parts of data that merely looked like index or ID address marks within tracks caused a resynchronisation of the tokeniser.

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This commit is contained in:
Thomas Harte 2016-09-27 07:36:37 -04:00
parent ca53fac732
commit 91235c7fd7
2 changed files with 50 additions and 39 deletions
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88
Components/1770/1770.cpp
View File

@ -18,7 +18,8 @@ WD1770::WD1770() :
resume_point_(0),
delay_time_(0),
index_hole_count_target_(-1),
is_awaiting_marker_value_(false)
is_awaiting_marker_value_(false),
is_reading_data_(false)
{
set_is_double_density(false);
posit_event(Event::Command);
@ -85,49 +86,52 @@ void WD1770::process_input_bit(int value, unsigned int cycles_since_index_hole)
bits_since_token_++;
Token::Type token_type = Token::Byte;
if(!is_double_density_)
if(!is_reading_data_)
{
switch(shift_register_ & 0xffff)
if(!is_double_density_)
{
case Storage::Encodings::MFM::FMIndexAddressMark:
token_type = Token::Index;
break;
case Storage::Encodings::MFM::FMIDAddressMark:
token_type = Token::ID;
break;
case Storage::Encodings::MFM::FMDataAddressMark:
token_type = Token::Data;
break;
case Storage::Encodings::MFM::FMDeletedDataAddressMark:
token_type = Token::DeletedData;
break;
default:
break;
switch(shift_register_ & 0xffff)
{
case Storage::Encodings::MFM::FMIndexAddressMark:
token_type = Token::Index;
break;
case Storage::Encodings::MFM::FMIDAddressMark:
token_type = Token::ID;
break;
case Storage::Encodings::MFM::FMDataAddressMark:
token_type = Token::Data;
break;
case Storage::Encodings::MFM::FMDeletedDataAddressMark:
token_type = Token::DeletedData;
break;
default:
break;
}
}
}
else
{
switch(shift_register_ & 0xffff)
else
{
case Storage::Encodings::MFM::MFMIndexAddressMark:
bits_since_token_ = 0;
is_awaiting_marker_value_ = true;
return;
case Storage::Encodings::MFM::MFMAddressMark:
bits_since_token_ = 0;
is_awaiting_marker_value_ = true;
return;
default:
break;
switch(shift_register_ & 0xffff)
{
case Storage::Encodings::MFM::MFMIndexAddressMark:
bits_since_token_ = 0;
is_awaiting_marker_value_ = true;
return;
case Storage::Encodings::MFM::MFMAddressMark:
bits_since_token_ = 0;
is_awaiting_marker_value_ = true;
return;
default:
break;
}
}
}
if(token_type != Token::Byte)
{
latest_token_.type = token_type;
bits_since_token_ = 0;
posit_event(Event::Token);
return;
if(token_type != Token::Byte)
{
latest_token_.type = token_type;
bits_since_token_ = 0;
posit_event(Event::Token);
return;
}
}
if(bits_since_token_ == 16)
@ -213,7 +217,7 @@ void WD1770::process_index_hole()
#define READ_ID() \
if(new_event_type == Event::Token) \
{ \
if(!distance_into_section_ && latest_token_.type == Token::ID) distance_into_section_++; \
if(!distance_into_section_ && latest_token_.type == Token::ID) {is_reading_data_ = true; distance_into_section_++; } \
else if(distance_into_section_ && distance_into_section_ < 7 && latest_token_.type == Token::Byte) \
{ \
header[distance_into_section_ - 1] = latest_token_.byte_value; \
@ -242,6 +246,7 @@ void WD1770::posit_event(Event new_event_type)
// Wait for a new command, branch to the appropriate handler.
wait_for_command:
printf("Idle...\n");
is_reading_data_ = false;
status_ &= ~Flag::Busy;
index_hole_count_ = 0;
WAIT_FOR_EVENT(Event::Command);
@ -331,9 +336,11 @@ void WD1770::posit_event(Event new_event_type)
}
if(distance_into_section_ == 7)
{
is_reading_data_ = false;
// TODO: CRC check
if(header[0] == track_)
{
printf("Reached track %d\n", track_);
status_ &= ~Flag::CRCError;
set_interrupt_request(true);
goto wait_for_command;
@ -381,6 +388,7 @@ void WD1770::posit_event(Event new_event_type)
}
if(distance_into_section_ == 7)
{
is_reading_data_ = false;
if(header[0] == track_ && header[2] == sector_)
{
// TODO: test CRC
@ -402,6 +410,7 @@ void WD1770::posit_event(Event new_event_type)
{
status_ |= (latest_token_.type == Token::DeletedData) ? Flag::RecordType : 0;
distance_into_section_ = 0;
is_reading_data_ = true;
goto type2_read_byte;
}
goto type2_read_data;
@ -434,6 +443,7 @@ void WD1770::posit_event(Event new_event_type)
goto test_type2_write_protection;
}
set_interrupt_request(true);
printf("Read sector %d\n", sector_);
goto wait_for_command;
}
goto type2_check_crc;

1
Components/1770/1770.hpp
View File

@ -55,6 +55,7 @@ class WD1770: public Storage::Disk::Controller {
void set_interrupt_request(bool interrupt_request) {}
// Tokeniser
bool is_reading_data_;
bool is_double_density_;
int shift_register_;
struct Token {