Added of_interpret for interpreting arbitrary Forth code.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@15588 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/platform/openfirmware/openfirmware.c

@@ -69,6 +69,56 @@ of_call_method(const char *method, int numArgs, int numReturns, ...)
 }
 
 
+int
+of_interpret(const char *command, int numArgs, int numReturns, ...)
+{
+	struct {
+		const char	*name;
+		int			num_args;
+		int			num_returns;
+			// "IN:	[string] cmd, stack_arg1, ..., stack_argP
+			// OUT:	catch-result, stack_result1, ..., stack_resultQ
+			// [...]
+			// An implementation shall allow at least six stack_arg and six
+			// stack_result items."
+		const char	*command;
+		void		*args[13];
+	} args = {"interpret", numArgs + 1, numReturns, command};
+	va_list list;
+	int i;
+
+	// iterate over all arguments and copy them into the
+	// structure passed over to the OpenFirmware
+
+	va_start(list, numReturns);
+	for (i = 0; i < numArgs; i++) {
+		// copy args
+		args.args[i] = (void *)va_arg(list, void *);
+	}
+	for (i = numArgs; i < numArgs + numReturns + 1; i++) {
+		// clear return values
+		args.args[i] = NULL;
+	}
+
+	// args.args[numArgs] is the "catch-result" return value
+	if (gCallOpenFirmware(&args) == OF_FAILED || args.args[numArgs])
+		return OF_FAILED;
+
+	if (numReturns > 0) {
+		// copy return values over to the provided location
+	
+		for (i = numArgs + 1; i < numArgs + 1 + numReturns; i++) {
+			void **store = va_arg(list, void **);
+			if (store)
+				*store = args.args[i];
+		}
+	}
+	va_end(list);
+
+	return 0;
+}
+
+
 int 
 of_finddevice(const char *device)
 {

src/system/boot/platform/openfirmware/openfirmware.h

@@ -65,6 +65,7 @@ extern void *of_claim(void *virtualAddress, int size, int align);
 
 /* misc functions */
 extern int of_call_method(const char *method, int numArgs, int numReturns, ...);
+extern int of_interpret(const char *command, int numArgs, int numReturns, ...);
 extern int of_test(const char *service);
 extern int of_milliseconds(void);
 extern void of_exit(void);