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test: middle ground for CRC lookup

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Compared to the baseline, -456 bytes of flash (90% of no lookup) but
claw back 3x the performance
This commit is contained in:
puddly
2026-09-09 19:07:31 +00:00
parent 020aef214b
commit 213ddf8823
1 changed files with 5 additions and 4 deletions
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esphome/components/zigbee_proxy/ash_protocol.cpp
+5 -4
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@@ -2,13 +2,14 @@
namespace esphome::zigbee_proxy {
static const uint16_t CRC_NIBBLE_TABLE[16] = {0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF};
uint16_t ash_crc16(const uint8_t *data, size_t length, uint16_t init) {
uint16_t crc = init;
for (size_t i = 0; i < length; i++) {
crc ^= static_cast<uint16_t>(data[i]) << 8;
for (uint8_t bit = 0; bit < 8; bit++) {
crc = (crc & 0x8000) ? static_cast<uint16_t>((crc << 1) ^ 0x1021) : static_cast<uint16_t>(crc << 1);
}
crc = static_cast<uint16_t>(crc << 4) ^ CRC_NIBBLE_TABLE[(crc >> 12) ^ (data[i] >> 4)];
crc = static_cast<uint16_t>(crc << 4) ^ CRC_NIBBLE_TABLE[(crc >> 12) ^ (data[i] & 0x0F)];
}
return crc;
}