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Improved average CV read time

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Anticipate more zeros than 1s in a typical CV value
This commit is contained in:
Asbelos 2020-06-07 17:02:22 +01:00
parent d1843fe38e
commit f2ee681479
1 changed files with 14 additions and 11 deletions
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25
DCC.cpp
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@ -145,15 +145,17 @@ const ackOp PROGMEM WRITE_BYTE_PROG[] = {
const ackOp PROGMEM READ_CV_PROG[] = {
BASELINE,
STARTMERGE, //clear bit and byte values ready for merge pass
// each bit is validated against 1 (no need for zero validation as entire byte is validated at the end)
V1, WACK, MERGE, // read and merge bit 0
V1, WACK, MERGE, // read and merge bit 1 etc
V1, WACK, MERGE,
V1, WACK, MERGE,
V1, WACK, MERGE,
V1, WACK, MERGE,
V1, WACK, MERGE,
V1, WACK, MERGE,
// each bit is validated against 0 and the result inverted in MERGE
// this is because there tend to be more zeros in cv values than ones.
// There is no need for one validation as entire byte is validated at the end
V0, WACK, MERGE, // read and merge bit 0
V0, WACK, MERGE, // read and merge bit 1 etc
V0, WACK, MERGE,
V0, WACK, MERGE,
V0, WACK, MERGE,
V0, WACK, MERGE,
V0, WACK, MERGE,
V0, WACK, MERGE,
VB, WACK, ITCB, // verify merged byte and return it if acked ok
FAIL }; // verification failed
@ -380,9 +382,10 @@ void DCC::ackManagerLoop() {
ackManagerByte=0;
break;
case MERGE: // Merge previous wack response with byte value and update bit number (use for reading CV bytes)
case MERGE: // Merge previous Validate zero wack response with byte value and update bit number (use for reading CV bytes)
ackManagerByte <<= 1;
if (ackReceived) ackManagerByte |= 1;
// ackReceived means bit is zero.
if (!ackReceived) ackManagerByte |= 1;
ackManagerBitNum--;
break;