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Attempts a full wiring up of fuzzy bits.

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This commit is contained in:
Thomas Harte 2020-01-19 21:20:21 -05:00
parent d27d14d2b0
commit da3ee381f4
2 changed files with 44 additions and 10 deletions
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52
Storage/Disk/Encodings/MFM/Encoder.cpp
View File

@ -29,7 +29,7 @@ class MFMEncoder: public Encoder {
void add_byte(uint8_t input, uint8_t fuzzy_mask = 0) final {
crc_generator_.add(input);
uint16_t spread_value =
const uint16_t spread_value =
static_cast<uint16_t>(
((input & 0x01) << 0) |
((input & 0x02) << 1) |
@ -40,9 +40,22 @@ class MFMEncoder: public Encoder {
((input & 0x40) << 6) |
((input & 0x80) << 7)
);
uint16_t or_bits = static_cast<uint16_t>((spread_value << 1) | (spread_value >> 1) | (last_output_ << 15));
uint16_t output = spread_value | ((~or_bits) & 0xaaaa);
output_short(output);
const uint16_t or_bits = static_cast<uint16_t>((spread_value << 1) | (spread_value >> 1) | (last_output_ << 15));
const uint16_t output = spread_value | ((~or_bits) & 0xaaaa);
const uint16_t spread_mask =
static_cast<uint16_t>(
((fuzzy_mask & 0x01) << 0) |
((fuzzy_mask & 0x02) << 1) |
((fuzzy_mask & 0x04) << 2) |
((fuzzy_mask & 0x08) << 3) |
((fuzzy_mask & 0x10) << 4) |
((fuzzy_mask & 0x20) << 5) |
((fuzzy_mask & 0x40) << 6) |
((fuzzy_mask & 0x80) << 7)
);
output_short(output, spread_mask);
}
void add_index_address_mark() final {
@ -76,9 +89,9 @@ class MFMEncoder: public Encoder {
private:
uint16_t last_output_;
void output_short(uint16_t value) final {
void output_short(uint16_t value, uint16_t fuzzy_mask = 0) final {
last_output_ = value;
Encoder::output_short(value);
Encoder::output_short(value, fuzzy_mask);
}
void output_sync() {
@ -105,7 +118,18 @@ class FMEncoder: public Encoder {
((input & 0x40) << 6) |
((input & 0x80) << 7) |
0xaaaa
));
),
static_cast<uint16_t>(
((fuzzy_mask & 0x01) << 0) |
((fuzzy_mask & 0x02) << 1) |
((fuzzy_mask & 0x04) << 2) |
((fuzzy_mask & 0x08) << 3) |
((fuzzy_mask & 0x10) << 4) |
((fuzzy_mask & 0x20) << 5) |
((fuzzy_mask & 0x40) << 6) |
((fuzzy_mask & 0x80) << 7)
)
);
}
void add_index_address_mark() final {
@ -248,10 +272,20 @@ void Encoder::reset_target(std::vector<bool> &target, std::vector<bool> *fuzzy_t
fuzzy_target_ = fuzzy_target;
}
void Encoder::output_short(uint16_t value) {
void Encoder::output_short(uint16_t value, uint16_t fuzzy_mask) {
const bool write_fuzzy_bits = fuzzy_mask;
if(write_fuzzy_bits) {
assert(fuzzy_target_);
// Zero-fill the bits to date, to cover any shorts written without fuzzy bits.
fuzzy_target_->resize(target_->size());
}
uint16_t mask = 0x8000;
while(mask) {
target_->push_back(!!(value & mask));
target_->push_back(value & mask);
if(write_fuzzy_bits) fuzzy_target_->push_back(fuzzy_mask & mask);
mask >>= 1;
}
}

2
Storage/Disk/Encodings/MFM/Encoder.hpp
View File

@ -53,7 +53,7 @@ class Encoder {
virtual void add_ID_address_mark() = 0;
virtual void add_data_address_mark() = 0;
virtual void add_deleted_data_address_mark() = 0;
virtual void output_short(uint16_t value);
virtual void output_short(uint16_t value, uint16_t fuzzy_mask = 0);
/// Outputs the CRC for all data since the last address mask; if @c incorrectly is @c true then outputs an incorrect CRC.
void add_crc(bool incorrectly);