prepare for custom chip clock rates

src/engine/dispatch.h

@@ -453,6 +453,18 @@ class DivDispatch {
      */
     virtual bool getWantPreNote();
 
+    /**
+     * get minimum chip clock.
+     * @return clock in Hz, or 0 if custom clocks are not supported.
+     */
+    virtual unsigned int getClockRangeMin();
+
+    /**
+     * get maximum chip clock.
+     * @return clock in Hz, or 0 if custom clocks are not supported.
+     */
+    virtual unsigned int getClockRangeMax();
+
     /**
      * set the chip flags.
      * @param flags a DivConfig containing chip flags.

src/engine/platform/abstract.cpp

@@ -97,6 +97,14 @@ bool DivDispatch::getWantPreNote() {
   return false;
 }
 
+unsigned int DivDispatch::getClockRangeMin() {
+  return 0;
+}
+
+unsigned int DivDispatch::getClockRangeMax() {
+  return 0;
+}
+
 void DivDispatch::setFlags(const DivConfig& flags) {
 }