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MMDVM
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Use pointer/masking/shifting for sample unpacking

This commit is contained in:
Geoffrey Merck 2020-05-08 17:41:12 +02:00
parent 604957b3e2
commit e3a951b33b
1 changed files with 8 additions and 12 deletions
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20
FM.cpp
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@ -643,21 +643,17 @@ uint8_t CFM::writeData(const uint8_t* data, uint8_t length)
for (uint8_t i = 0U; i < length; i += 3U) {
uint16_t sample1 = 0U;
uint16_t sample2 = 0U;
uint16_t MASK = 0x0001U;
uint32_t MASK = 0x00000FFFU;
const uint8_t* base = data + i;
for (uint8_t j = 0U; j < 12U; j++, MASK <<= 1) {
uint8_t pos1 = j;
uint8_t pos2 = j + 12U;
uint32_t pack = 0U;
uint8_t* packPointer = (uint8_t*)&pack;
bool b1 = READ_BIT_AUDIO(base, pos1) != 0U;
bool b2 = READ_BIT_AUDIO(base, pos2) != 0U;
packPointer[1U] = data[i];
packPointer[2U] = data[i + 1U];
packPointer[3U] = data[i + 2U];
if (b1)
sample1 |= MASK;
if (b2)
sample2 |= MASK;
}
sample2 = uint16_t(pack & MASK);
sample1 = uint16_t(pack >> 12);
// Convert from uint16_t (0 - +4095) to Q15 (-2048 - +2047)
samples[nSamples++] = q15_t(sample1) - 2048;