1 files changed, 49 insertions, 0 deletions
diff --git a/src/opcodes.c b/src/opcodes.c
new file mode 100644
index 0000000..5bc30ef
--- /dev/null
+++ b/src/opcodes.c
@@ -0,0 +1,49 @@
+/*
+    opcodes.cpp
+    Copyright (C) 2021 Richard Knight
+
+
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 3 of the License, or (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software Foundation,
+    Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ 
+ */
+
+
+#include "csdl.h"
+
+// struct for numeric opcode
+typedef struct _nstrexists_t {
+	OPDS h;
+	MYFLT *out;
+	MYFLT *in;
+} nstrexists_t;
+
+
+// numeric opcode
+int nstrexists(CSOUND *csound, nstrexists_t *p) {
+	if (NULL != csound->GetInstrument(csound, (int)*p->in, NULL)) {
+		*(p->out) = FL(1);
+	} else {
+		*(p->out) = FL(0);
+	}
+	return OK;
+}
+
+
+static OENTRY localops[] = {
+	{"nstrexists", sizeof(nstrexists_t), 0, 1, "i", "i", (SUBR) nstrexists, NULL, NULL},
+	{"nstrexists.k", sizeof(nstrexists_t), 0, 3, "k", "k", (SUBR) nstrexists, (SUBR) nstrexists, NULL},
+};
+
+LINKAGE