Add ovni_mark_set() to the API

Allows emitting a single event to change the value of the mark channel.
The mark type must be defined as single without the MARK_FLAG_STACK
flag.

include/ovni.h.in

@@ -150,6 +150,7 @@ void ovni_mark_type(int32_t type, long flags, const char *title);
 void ovni_mark_label(int32_t type, int64_t value, const char *label);
 void ovni_mark_push(int32_t type, int64_t value);
 void ovni_mark_pop(int32_t type, int64_t value);
+void ovni_mark_set(int32_t type, int64_t value);
 
 #ifdef __cplusplus
 }

src/emu/ovni/mark.c

@@ -478,6 +478,8 @@ mark_event(struct emu *emu)
 			return chan_push(ch, value_int64(value));
 		case ']':
 			return chan_pop(ch, value_int64(value));
+		case '=':
+			return chan_set(ch, value_int64(value));
 		default:
 			err("unknown mark event value %c", emu->ev->v);
 			return -1;

src/emu/ovni/setup.c

@@ -40,6 +40,7 @@ static struct ev_decl model_evlist[] = {
 
 	{ "OM[(i64 value, i32 type)", "push mark with value %{value} from type %{type}" },
 	{ "OM](i64 value, i32 type)", "pop mark with value %{value} from type %{type}" },
+	{ "OM=(i64 value, i32 type)", "set mark with value %{value} from type %{type}" },
 
 	{ NULL, NULL },
 };

src/rt/ovni.c

@@ -1154,3 +1154,14 @@ ovni_mark_pop(int32_t type, int64_t value)
 	ovni_payload_add(&ev, (uint8_t *) &type, sizeof(type));
 	ovni_ev_add(&ev);
 }
+
+void
+ovni_mark_set(int32_t type, int64_t value)
+{
+	struct ovni_ev ev = {0};
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_ev_set_mcv(&ev, "OM=");
+	ovni_payload_add(&ev, (uint8_t *) &value, sizeof(value));
+	ovni_payload_add(&ev, (uint8_t *) &type, sizeof(type));
+	ovni_ev_add(&ev);
+}