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common/xpfloat.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program 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 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef COMMON_XPFLOAT_H
+#define COMMON_XPFLOAT_H
+
+// 80-bit extended precision floating point
+// Mostly encountered stored as data on Apple systems
+
+#include "common/scummsys.h"
+
+namespace Common {
+
+struct XPFloat {
+	uint16 signAndExponent;
+	uint64 mantissa;
+
+	enum Semantics {
+		kSemanticsMC68881,
+		kSemanticsSANE = kSemanticsMC68881,
+
+		// Could add Intel 8087 and derivatives here since they're mostly compatible,
+		// but have different NaN/INF flag cases.
+	};
+
+	XPFloat();
+	XPFloat(uint16 signAndExponent, uint64 mantissa);
+
+	static XPFloat fromDouble(double value, Semantics semantics = kSemanticsMC68881);
+	static XPFloat fromDoubleBits(uint64 value, Semantics semantics = kSemanticsMC68881);
+
+	void toDoubleSafe(double &result, bool &outOverflowed, Semantics semantics = kSemanticsMC68881) const;
+	void toDoubleBitsSafe(uint64 &result, bool &outOverflowed, Semantics semantics = kSemanticsMC68881) const;
+
+	// Simple version that clamps to infinity and warns on overflow
+	double toDouble(Semantics semantics = kSemanticsMC68881) const;
+};
+
+inline XPFloat::XPFloat() : signAndExponent(0), mantissa(0) {}
+inline XPFloat::XPFloat(uint16 fSignAndExponent, uint64 fMantissa) : signAndExponent(fSignAndExponent), mantissa(fMantissa) {}
+
+}
+
+#endif