1 files changed, 73 insertions, 0 deletions
diff --git a/src/engine/util.h b/src/engine/util.h
new file mode 100644
index 00000000..9cf4bf7f
--- /dev/null
+++ b/src/engine/util.h
@@ -0,0 +1,73 @@
+/* This file is part of Om.  Copyright (C) 2006 Dave Robillard.
+ * 
+ * Om is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any later
+ * version.
+ * 
+ * Om 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 General Public License for 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.,
+ * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef UTIL_H
+#define UTIL_H
+
+#include <iostream>
+#include <cstdlib>
+
+#include <fenv.h>
+#ifdef __SSE__
+#include <xmmintrin.h>
+#endif
+
+using std::cerr; using std::endl;
+
+namespace Om {
+
+/** Set flags to disable denormal processing.
+ */
+inline void
+set_denormal_flags()
+{
+#ifdef __SSE__
+	unsigned long a, b, c, d;
+
+	asm("cpuid": "=a" (a), "=b" (b), "=c" (c), "=d" (d) : "a" (1));
+	if (d & 1<<25) { /* It has SSE support */
+		_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
+
+		asm("cpuid": "=a" (a), "=b" (b), "=c" (c), "=d" (d) : "a" (0));
+		if (b == 0x756e6547) { /* It's an Intel */
+			int stepping, model, family, extfamily;
+
+			family = (a >> 8) & 0xf;
+			extfamily = (a >> 20) & 0xff;
+			model = (a >> 4) & 0xf;
+			stepping = a & 0xf;
+			if (family == 15 && extfamily == 0 && model == 0 && stepping < 7) {
+				return;
+			}
+		}
+		asm("cpuid": "=a" (a), "=b" (b), "=c" (c), "=d" (d) : "a" (1));
+		if (d & 1<<26) { /* bit 26, SSE2 support */
+			_mm_setcsr(_mm_getcsr() | 0x40);
+			//cerr << "Set SSE denormal fix flag." << endl;
+		}
+	} else {
+		cerr << "This code has been built with SSE support, but your processor does"
+			<< " not support the SSE instruction set." << endl << "Exiting." << endl;
+		exit(EXIT_FAILURE);
+	}
+#endif
+	// Set 387 control register via standard C99 interface
+	fesetround(FE_TOWARDZERO);
+}
+
+} // namespace Om
+
+#endif // UTIL_H