X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Foutput%2Fvcd.c;h=3de3dcde37b3a044679ed745e498433c987aa047;hb=7c41c420aa51b07e7381df5132da27228e9a56bd;hp=479f331cd838b2d5763029a32b0e221e46e75ee9;hpb=a755b0e122105d934c4e7b97435420eda6df6e8e;p=libsigrok.git
diff --git a/src/output/vcd.c b/src/output/vcd.c
index 479f331c..3de3dcde 100644
--- a/src/output/vcd.c
+++ b/src/output/vcd.c
@@ -15,33 +15,28 @@
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ * along with this program; if not, see .
*/
+#include
#include
#include
#include
-#include "config.h" /* Needed for PACKAGE and others. */
-#include "libsigrok.h"
+#include
#include "libsigrok-internal.h"
#define LOG_PREFIX "output/vcd"
struct context {
int num_enabled_channels;
- GArray *channelindices;
uint8_t *prevsample;
gboolean header_done;
- int period;
+ uint64_t period;
int *channel_index;
uint64_t samplerate;
uint64_t samplecount;
};
-static const char *const vcd_header_comment =
- "$comment\n Acquisition with %d/%d channels at %s\n$end\n";
-
static int init(struct sr_output *o, GHashTable *options)
{
struct context *ctx;
@@ -66,7 +61,7 @@ static int init(struct sr_output *o, GHashTable *options)
}
ctx = g_malloc0(sizeof(struct context));
- o->internal = ctx;
+ o->priv = ctx;
ctx->num_enabled_channels = num_enabled_channels;
ctx->channel_index = g_malloc(sizeof(int) * ctx->num_enabled_channels);
@@ -83,6 +78,38 @@ static int init(struct sr_output *o, GHashTable *options)
return SR_OK;
}
+/*
+ * VCD can only handle 1/10/100 factors in the s to fs range. Find a
+ * suitable timescale which satisfies this resolution constraint, yet
+ * won't result in excessive overhead.
+ */
+static uint64_t get_timescale_freq(uint64_t samplerate)
+{
+ uint64_t timescale;
+ int max_up_scale;
+
+ /* Go to the next full decade. */
+ timescale = 1;
+ while (timescale < samplerate) {
+ timescale *= 10;
+ }
+
+ /*
+ * Avoid loss of precision, go up a few more decades when needed.
+ * For example switch to 10GHz timescale when samplerate is 400MHz.
+ * Stop after at most factor 100 to not loop endlessly for odd
+ * samplerates, yet provide good enough accuracy.
+ */
+ max_up_scale = 2;
+ while (max_up_scale--) {
+ if (timescale / samplerate * samplerate == timescale)
+ break;
+ timescale *= 10;
+ }
+
+ return timescale;
+}
+
static GString *gen_header(const struct sr_output *o)
{
struct context *ctx;
@@ -94,20 +121,20 @@ static GString *gen_header(const struct sr_output *o)
int num_channels, i;
char *samplerate_s, *frequency_s, *timestamp;
- ctx = o->internal;
+ ctx = o->priv;
header = g_string_sized_new(512);
num_channels = g_slist_length(o->sdi->channels);
/* timestamp */
t = time(NULL);
timestamp = g_strdup(ctime(&t));
- timestamp[strlen(timestamp)-1] = 0;
+ timestamp[strlen(timestamp) - 1] = 0;
g_string_printf(header, "$date %s $end\n", timestamp);
g_free(timestamp);
/* generator */
g_string_append_printf(header, "$version %s %s $end\n",
- PACKAGE, PACKAGE_VERSION);
+ PACKAGE_NAME, sr_package_version_string_get());
g_string_append_printf(header, "$comment\n Acquisition with "
"%d/%d channels", ctx->num_enabled_channels, num_channels);
@@ -126,22 +153,16 @@ static GString *gen_header(const struct sr_output *o)
g_string_append_printf(header, "\n$end\n");
/* timescale */
- /* VCD can only handle 1/10/100 (s - fs), so scale up first */
- if (ctx->samplerate > SR_MHZ(1))
- ctx->period = SR_GHZ(1);
- else if (ctx->samplerate > SR_KHZ(1))
- ctx->period = SR_MHZ(1);
- else
- ctx->period = SR_KHZ(1);
- frequency_s = sr_period_string(ctx->period);
+ ctx->period = get_timescale_freq(ctx->samplerate);
+ frequency_s = sr_period_string(1, ctx->period);
g_string_append_printf(header, "$timescale %s $end\n", frequency_s);
g_free(frequency_s);
/* scope */
- g_string_append_printf(header, "$scope module %s $end\n", PACKAGE);
+ g_string_append_printf(header, "$scope module %s $end\n", PACKAGE_NAME);
/* Wires / channels */
- for (i = 0, l = o->sdi->channels; l; l = l->next, i++) {
+ for (i = 0, l = o->sdi->channels; l; l = l->next) {
ch = l->data;
if (ch->type != SR_CHANNEL_LOGIC)
continue;
@@ -149,6 +170,7 @@ static GString *gen_header(const struct sr_output *o)
continue;
g_string_append_printf(header, "$var wire 1 %c %s $end\n",
(char)('!' + i), ch->name);
+ i++;
}
g_string_append(header, "$upscope $end\n$enddefinitions $end\n");
@@ -170,9 +192,9 @@ static int receive(const struct sr_output *o, const struct sr_datafeed_packet *p
gboolean timestamp_written;
*out = NULL;
- if (!o || !o->internal)
+ if (!o || !o->priv)
return SR_ERR_BUG;
- ctx = o->internal;
+ ctx = o->priv;
switch (packet->type) {
case SR_DF_META:
@@ -204,7 +226,16 @@ static int receive(const struct sr_output *o, const struct sr_datafeed_packet *p
timestamp_written = FALSE;
for (p = 0; p < ctx->num_enabled_channels; p++) {
- index = ctx->channel_index[p];
+ /*
+ * TODO Check whether the mapping from
+ * data image positions to channel numbers
+ * is required. Experiments suggest that
+ * the data image "is dense", and packs
+ * bits of enabled channels, and leaves no
+ * room for positions of disabled channels.
+ */
+ /* index = ctx->channel_index[p]; */
+ index = p;
curbit = ((unsigned)sample[index / 8]
>> (index % 8)) & 1;
@@ -251,10 +282,10 @@ static int cleanup(struct sr_output *o)
{
struct context *ctx;
- if (!o || !o->internal)
+ if (!o || !o->priv)
return SR_ERR_ARG;
- ctx = o->internal;
+ ctx = o->priv;
g_free(ctx->prevsample);
g_free(ctx->channel_index);
g_free(ctx);
@@ -265,7 +296,9 @@ static int cleanup(struct sr_output *o)
struct sr_output_module output_vcd = {
.id = "vcd",
.name = "VCD",
- .desc = "Value Change Dump",
+ .desc = "Value Change Dump data",
+ .exts = (const char*[]){"vcd", NULL},
+ .flags = 0,
.options = NULL,
.init = init,
.receive = receive,