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CRCs are just stored reversed. Of course. So this should be sufficient to load each chunk of an Acorn file.

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This commit is contained in:
Thomas Harte 2016-08-30 08:13:40 -04:00
parent b3521ed187
commit 7b5d5858ff
1 changed files with 27 additions and 6 deletions
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33
StaticAnalyser/Acorn/Tape.cpp
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@ -156,8 +156,8 @@ static std::unique_ptr<File::Chunk> GetNextChunk(TapeParser &parser)
std::unique_ptr<File::Chunk> new_chunk(new File::Chunk);
int shift_register = 0;
#define shift() \
shift_register = (shift_register >> 1) | (parser.get_next_bit() << 9)
// TODO: move this into the parser
#define shift() shift_register = (shift_register >> 1) | (parser.get_next_bit() << 9)
// find next area of high tone
while(!parser.is_at_end() && (shift_register != 0x3ff))
@ -171,6 +171,8 @@ static std::unique_ptr<File::Chunk> GetNextChunk(TapeParser &parser)
shift();
}
#undef shift
parser.reset_crc();
parser.reset_error_flag();
@ -192,12 +194,31 @@ static std::unique_ptr<File::Chunk> GetNextChunk(TapeParser &parser)
new_chunk->block_flag = (uint8_t)parser.get_next_byte();
new_chunk->next_address = (uint32_t)parser.get_next_word();
uint16_t calculated_crc = parser.get_crc();
uint16_t stored_crc = (uint16_t)parser.get_next_short();
uint16_t calculated_header_crc = parser.get_crc();
uint16_t stored_header_crc = (uint16_t)parser.get_next_short();
stored_header_crc = (uint16_t)((stored_header_crc >> 8) | (stored_header_crc << 8));
new_chunk->header_crc_matched = stored_header_crc == calculated_header_crc;
printf("%04x v %04x", calculated_crc, stored_crc);
parser.reset_crc();
new_chunk->data.reserve(new_chunk->block_length);
for(int c = 0; c < new_chunk->block_length; c++)
{
new_chunk->data.push_back((uint8_t)parser.get_next_byte());
}
return nullptr;
if(new_chunk->block_length)
{
uint16_t calculated_data_crc = parser.get_crc();
uint16_t stored_data_crc = (uint16_t)parser.get_next_short();
stored_data_crc = (uint16_t)((stored_data_crc >> 8) | (stored_data_crc << 8));
new_chunk->data_crc_matched = stored_data_crc == calculated_data_crc;
}
else
{
new_chunk->data_crc_matched = true;
}
return parser.get_error_flag() ? nullptr : std::move(new_chunk);
}
std::unique_ptr<File> StaticAnalyser::Acorn::GetNextFile(const std::shared_ptr<Storage::Tape::Tape> &tape)