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Improve lf sampling performance

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Signed-off-by: yah01 <yah2er0ne@outlook.com>
This commit is contained in:
yah01 2023-10-27 13:47:26 +08:00
commit 9d07ee497c
2 changed files with 15 additions and 21 deletions
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1
CHANGELOG.md
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@ -39,6 +39,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
- Modified `hf iclass configcard` to only support online mode (@Antiklesys)
- Modified `hf iclass configcard` command to generate config cards without a cardhelper module by porting the contents of blocks 6 & 7 from nfc-iclass (@Antiklesys)
- Fixed `hf iclass info` command showing incorrectly in offline mode (@Antiklesys)
- Changed lf sampling - improved the performance (@yah01)
## [Raccoon.4.17140][2023-09-09]
- Changed text and adjust pm3_test case for mf_aes_brute (@doegox)

35
armsrc/lfsampling.c
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@ -128,20 +128,6 @@ sample_config *getSamplingConfig(void) {
return &config;
}
/**
* @brief Pushes bit onto the stream
* @param stream
* @param bit
*/
static void pushBit(BitstreamOut_t *stream, uint8_t bit) {
int bytepos = stream->position >> 3; // divide by 8
int bitpos = stream->position & 7;
*(stream->buffer + bytepos) &= ~(1 << (7 - bitpos));
*(stream->buffer + bytepos) |= (bit > 0) << (7 - bitpos);
stream->position++;
stream->numbits++;
}
void initSampleBuffer(uint32_t *sample_size) {
initSampleBufferEx(sample_size, false);
}
@ -233,13 +219,20 @@ void logSample(uint8_t sample, uint8_t decimation, uint8_t bits_per_sample, bool
data.numbits = samples.total_saved << 3;
} else {
pushBit(&data, sample & 0x80);
if (bits_per_sample > 1) pushBit(&data, sample & 0x40);
if (bits_per_sample > 2) pushBit(&data, sample & 0x20);
if (bits_per_sample > 3) pushBit(&data, sample & 0x10);
if (bits_per_sample > 4) pushBit(&data, sample & 0x08);
if (bits_per_sample > 5) pushBit(&data, sample & 0x04);
if (bits_per_sample > 6) pushBit(&data, sample & 0x02);
// truncate trailing data
sample >>= 8 - bits_per_sample;
sample <<= 8 - bits_per_sample;
uint8_t bits_offset = data.numbits & 0x7;
uint8_t bits_cap = 8 - bits_offset;
// write the current byte
data.buffer[data.numbits >> 3] |= sample >> bits_offset;
int numbits = data.numbits + bits_cap;
// write the remaining bits to the next byte
data.buffer[numbits >> 3] |= sample << (bits_cap);
data.numbits += bits_per_sample;
}
}