1 files changed, 34 insertions, 0 deletions
diff --git a/lib/ppc/floatditf.c b/lib/ppc/floatditf.c
new file mode 100644
index 00000000..081dc8cb
--- /dev/null
+++ b/lib/ppc/floatditf.c
@@ -0,0 +1,34 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// long double __floatditf(long long x);
+// This file implements the PowerPC long long -> long double conversion
+
+#include "DD.h"
+#include <stdint.h>
+
+long double __floatditf(int64_t a) {
+	
+	static const double twop32 = 0x1.0p32;
+	static const double twop52 = 0x1.0p52;
+	
+	doublebits low  = { .d = twop52 };
+	low.x |= a & UINT64_C(0x00000000ffffffff);	// 0x1.0p52 + low 32 bits of a.
+	
+	const double high_addend = (double)((int32_t)(a >> 32))*twop32 - twop52;
+	
+	// At this point, we have two double precision numbers
+	// high_addend and low.d, and we wish to return their sum
+	// as a canonicalized long double:
+	
+	// This implementation sets the inexact flag spuriously.
+	// This could be avoided, but at some substantial cost.
+	
+	DD result;
+	
+	result.hi = high_addend + low.d;
+	result.lo = (high_addend - result.hi) + low.d;
+	
+	return result.ld;
+	
+}