X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=output%2Foutput_vcd.c;h=eea2f0e5bcd1997ee21b28f86e8f8a8bfe0d0110;hb=340f6e7aeaf0c6cbbb27c5b535787bd09407994b;hp=a9f794ad9762dbf70599d69cf2a24ab746330128;hpb=086eac7c7bef114dd96c6ddb639fa2fa35f9182b;p=libsigrok.git

diff --git a/output/output_vcd.c b/output/output_vcd.c
index a9f794ad..eea2f0e5 100644
--- a/output/output_vcd.c
+++ b/output/output_vcd.c
@@ -61,12 +61,15 @@ static int init(struct output *o)
 
 	if (!(ctx = calloc(1, sizeof(struct context))))
 		return SIGROK_ERR_MALLOC;
+
 	o->internal = ctx;
 	ctx->num_enabled_probes = 0;
+
 	for (l = o->device->probes; l; l = l->next) {
 		probe = l->data;
-		if (probe->enabled)
-			ctx->probelist[ctx->num_enabled_probes++] = probe->name;
+		if (!probe->enabled)
+			continue;
+		ctx->probelist[ctx->num_enabled_probes++] = probe->name;
 	}
 
 	ctx->probelist[ctx->num_enabled_probes] = 0;
@@ -183,22 +186,20 @@ static int data(struct output *o, char *data_in, uint64_t length_in,
 	for (i = 0; i <= length_in - ctx->unitsize; i += ctx->unitsize) {
 		samplecount++;
 		memcpy(&sample, data_in + i, ctx->unitsize);
+		if (i == 0)
+			prevsample = sample;
+		else
+			memcpy(&prevsample, data_in + i - 1, ctx->unitsize);
+
 		for (p = 0; p < ctx->num_enabled_probes; p++) {
-			curbit = (sample & ((uint64_t) (1 << p))) != 0;
-			if (i == 0) {
-				prevbit = ~curbit;
-			} else {
-				memcpy(&prevsample, data_in + i - 1,
-				       ctx->unitsize);
-				prevbit =
-				    (prevsample & ((uint64_t) (1 << p))) != 0;
-			}
-
-			/* VCD only contains deltas/changes. */
+			curbit = (sample & ((uint64_t) (1 << p))) >> p;
+			prevbit = (prevsample & ((uint64_t) (1 << p))) >> p;
+
+			/* VCD only contains deltas/changes of signals. */
 			if (prevbit == curbit)
 				continue;
 
-			/* FIXME: Only once per sample? */
+			/* Output which signal changed to which value. */
 			c = outbuf + strlen(outbuf);
 			sprintf(c, "#%" PRIu64 "\n%i%c\n", samplecount,
 				curbit, (char)('!' + p));