1 files changed, 40 insertions, 0 deletions
diff --git a/lib/ppc/floatunditf.c b/lib/ppc/floatunditf.c
new file mode 100644
index 000000000..63f0b4467
--- /dev/null
+++ b/lib/ppc/floatunditf.c
@@ -0,0 +1,40 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// long double __floatunditf(unsigned long long x);
+// This file implements the PowerPC unsigned long long -> long double conversion
+
+#include "DD.h"
+#include <stdint.h>
+
+long double __floatunditf(uint64_t a) {
+	
+	// Begins with an exact copy of the code from __floatundidf
+	
+	static const double twop52 = 0x1.0p52;
+	static const double twop84 = 0x1.0p84;
+	static const double twop84_plus_twop52 = 0x1.00000001p84;
+	
+	doublebits high = { .d = twop84 };
+	doublebits low  = { .d = twop52 };
+	
+	high.x |= a >> 32;							// 0x1.0p84 + high 32 bits of a
+	low.x |= a & UINT64_C(0x00000000ffffffff);	// 0x1.0p52 + low 32 bits of a
+	
+	const double high_addend = high.d - twop84_plus_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;
+	
+}