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Now the CRC is a factoring out.

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This commit is contained in:
Thomas Harte 2016-09-18 18:35:50 -04:00
parent 180c3df2d4
commit 5ebca62bba
1 changed files with 8 additions and 15 deletions
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23
StaticAnalyser/Acorn/Tape.cpp
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@ -10,6 +10,7 @@
#include <deque> #include <deque>
#include "../TapeParser.hpp" #include "../TapeParser.hpp"
#include "../../NumberTheory/CRC.hpp"
using namespace StaticAnalyser::Acorn; using namespace StaticAnalyser::Acorn;
@ -23,7 +24,9 @@ enum class SymbolType {
class Acorn1200BaudTapeParser: public StaticAnalyer::TapeParser<WaveType, SymbolType> { class Acorn1200BaudTapeParser: public StaticAnalyer::TapeParser<WaveType, SymbolType> {
public: public:
Acorn1200BaudTapeParser(const std::shared_ptr<Storage::Tape::Tape> &tape) : TapeParser(tape) {} Acorn1200BaudTapeParser(const std::shared_ptr<Storage::Tape::Tape> &tape) :
TapeParser(tape),
_crc(0x1021, 0x0000) {}
int get_next_bit() int get_next_bit()
{ {
@ -49,7 +52,7 @@ class Acorn1200BaudTapeParser: public StaticAnalyer::TapeParser<WaveType, Symbol
set_error_flag(); set_error_flag();
return -1; return -1;
} }
add_to_crc((uint8_t)value); _crc.add((uint8_t)value);
return value; return value;
} }
@ -67,8 +70,8 @@ class Acorn1200BaudTapeParser: public StaticAnalyer::TapeParser<WaveType, Symbol
return result; return result;
} }
void reset_crc() { _crc = 0; } void reset_crc() { _crc.reset(); }
uint16_t get_crc() { return _crc; } uint16_t get_crc() { return _crc.get_value(); }
private: private:
void process_pulse(Storage::Tape::Tape::Pulse pulse) void process_pulse(Storage::Tape::Tape::Pulse pulse)
@ -111,17 +114,7 @@ class Acorn1200BaudTapeParser: public StaticAnalyer::TapeParser<WaveType, Symbol
remove_waves(1); remove_waves(1);
} }
void add_to_crc(uint8_t value) NumberTheory::CRC16 _crc;
{
_crc ^= (uint16_t)value << 8;
for(int c = 0; c < 8; c++)
{
uint16_t exclusive_or = (_crc&0x8000) ? 0x1021 : 0x0000;
_crc = (uint16_t)(_crc << 1) ^ exclusive_or;
}
}
uint16_t _crc;
}; };
static std::unique_ptr<File::Chunk> GetNextChunk(Acorn1200BaudTapeParser &parser) static std::unique_ptr<File::Chunk> GetNextChunk(Acorn1200BaudTapeParser &parser)