SBEFIFO_STS
rc = sbefifo_regr(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &status);
rc = sbefifo_regr(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &up_status);
rc = sbefifo_regr(sbefifo, SBEFIFO_DOWN | SBEFIFO_STS, &down_status);
addr = (up ? SBEFIFO_UP : SBEFIFO_DOWN) | SBEFIFO_STS;