VAC_FRAMESIZE
blk &= ~(VAC_FRAMESIZE - 1);
if (blk < VAC_FRAMESIZE)
blk = VAC_FRAMESIZE;
n = sc->sc_pblksize / VAC_FRAMESIZE;
uint8_t * const d = sc->sc_dpstage + i * VAC_FRAMESIZE;
p += VAC_FRAMESIZE;
sc->sc_dpstage, n * VAC_FRAMESIZE);
#define VAC_DP_BUFBYTES (VAC_DP_MAXFRAMES * VAC_FRAMESIZE)