X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fdmm%2Fbm25x.c;h=b838d1ce73b5dda3744118ef69858e974e7229f8;hb=HEAD;hp=d7468f49bfd300a5dd303da470bdad42810bec64;hpb=b02bb45f4cf6378520e5a5b82ff39013cfa270b6;p=libsigrok.git

diff --git a/src/dmm/bm25x.c b/src/dmm/bm25x.c
index d7468f49..b838d1ce 100644
--- a/src/dmm/bm25x.c
+++ b/src/dmm/bm25x.c
@@ -94,36 +94,31 @@ static int decode_point(const uint8_t *buf)
 	return p;
 }
 
-static float scale_value(float val, int point, int digits)
+static int decode_scale(int point, int digits)
 {
 	int pos;
 
 	pos = point ? point + digits - MAX_DIGITS : 0;
 
-	switch (pos) {
-	case 0: return val;
-	case 1: return val * 1e-1;
-	case 2: return val * 1e-2;
-	case 3: return val * 1e-3;
+	if (pos < 0 || pos > 3) {
+		sr_dbg("Invalid decimal point %d (%d digits).", point, digits);
+		return 0;
 	}
-
-	sr_dbg("Invalid decimal point %d (%d digits).", point, digits);
-
-	return NAN;
+	return -pos;
 }
 
-static float decode_prefix(const uint8_t *buf)
+static int decode_prefix(const uint8_t *buf)
 {
-	if (buf[11] & 2) return 1e+6;
-	if (buf[11] & 1) return 1e+3;
-	if (buf[13] & 1) return 1e-3;
-	if (buf[13] & 2) return 1e-6;
-	if (buf[12] & 1) return 1e-9;
+	if (buf[11] & 2) return  6;
+	if (buf[11] & 1) return  3;
+	if (buf[13] & 1) return -3;
+	if (buf[13] & 2) return -6;
+	if (buf[12] & 1) return -9;
 
-	return 1.0f;
+	return 0;
 }
 
-static float decode_value(const uint8_t *buf)
+static float decode_value(const uint8_t *buf, int *exponent)
 {
 	float val = 0.0f;
 	int i, digit;
@@ -137,7 +132,8 @@ static float decode_value(const uint8_t *buf)
 		val = 10.0 * val + digit;
 	}
 
-	return scale_value(val, decode_point(buf), i);
+	*exponent = decode_scale(decode_point(buf), i);
+	return val;
 
 special:
 	if (decode_digit(1, buf) == 0 && decode_digit(2, buf) == 'L')
@@ -149,6 +145,7 @@ special:
 SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval,
 				struct sr_datafeed_analog *analog, void *info)
 {
+	int exponent = 0;
 	float val;
 
 	(void)info;
@@ -176,7 +173,7 @@ SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval,
 		analog->meaning->mq = SR_MQ_VOLTAGE;
 		analog->meaning->unit = SR_UNIT_VOLT;
 		if ((analog->meaning->mqflags & (SR_MQFLAG_DC | SR_MQFLAG_AC)) == 0)
-			analog->meaning->mqflags |= SR_MQFLAG_DIODE;
+			analog->meaning->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
 	}
 	if (buf[14] & 2) {
 		analog->meaning->mq = SR_MQ_CURRENT;
@@ -204,12 +201,16 @@ SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval,
 		analog->meaning->unit = SR_UNIT_FAHRENHEIT;
 	}
 
-	val = decode_value(buf) * decode_prefix(buf);
+	val = decode_value(buf, &exponent);
+	exponent += decode_prefix(buf);
+	val *= powf(10, exponent);
 
 	if (buf[3] & 1)
 		val = -val;
 
 	*floatval = val;
+	analog->encoding->digits = -exponent;
+	analog->spec->spec_digits = -exponent;
 
 	return SR_OK;
 }