libgsmhr1 TFO: require BFI=0 and SID=0 for homing In order for a received frame to be recognized as DHF, we need not only the correct bit pattern, but also BFI=0 and SID=0. The BFI=0 requirement should be obvious, while the SID=0 requirement is needed only for HR codec. With FR and EFR, SID classification comes from the payload bits and no separate check is needed - but in HR we get an out-of-band SID ternary flag. When SID=1, no payload bits are used at all; when SID=2, we use only the first 33 bits of the payload. Therefore, it is proper to conditionalize DHF acceptance on SID=0. We already implemented this logic in the just finished full decoder; now bring TFO code into agreement.

/*
 * A cleaner reimplementation of AMR Prm2bits() function.
 */

#include "typedef.h"
#include "namespace.h"
#include "bitno.h"
#include "prm2bits.h"

void Prm2bits(enum Mode mode, const Word16 prm[], Word16 bits[])
{
	const Word16 *t = bitno[mode];
	unsigned nparam = prmno[mode];
	unsigned n, p, mask;
	Word16 *b = bits;

	for (n = 0; n < nparam; n++) {
		p = prm[n];
		mask = 1 << (*t++ - 1);
		for (; mask; mask >>= 1) {
			if (p & mask)
				*b++ = 1;
			else
				*b++ = 0;
		}
	}
}