1 files changed, 59 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/builtins/ppc/fixunstfdi.c b/contrib/compiler-rt/lib/builtins/ppc/fixunstfdi.c
new file mode 100644
index 000000000000..5e6e2cedf6ac
--- /dev/null
+++ b/contrib/compiler-rt/lib/builtins/ppc/fixunstfdi.c
@@ -0,0 +1,59 @@
+/* This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ */
+
+/* uint64_t __fixunstfdi(long double x); */
+/* This file implements the PowerPC 128-bit double-double -> uint64_t conversion */
+
+#include "DD.h"
+
+uint64_t __fixunstfdi(long double input)
+{
+	const DD x = { .ld = input };
+	const doublebits hibits = { .d = x.s.hi };
+	
+	const uint32_t highWordMinusOne = (uint32_t)(hibits.x >> 32) - UINT32_C(0x3ff00000);
+	
+	/* If (1.0 - tiny) <= input < 0x1.0p64: */
+	if (UINT32_C(0x04000000) > highWordMinusOne)
+	{
+		const int unbiasedHeadExponent = highWordMinusOne >> 20;
+		
+		uint64_t result = hibits.x & UINT64_C(0x000fffffffffffff); /* mantissa(hi) */
+		result |= UINT64_C(0x0010000000000000); /* matissa(hi) with implicit bit */
+		result <<= 11; /* mantissa(hi) left aligned in the int64 field. */
+		
+		/* If the tail is non-zero, we need to patch in the tail bits. */
+		if (0.0 != x.s.lo)
+		{
+			const doublebits lobits = { .d = x.s.lo };
+			int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff);
+			tailMantissa |= INT64_C(0x0010000000000000);
+			
+			/* At this point we have the mantissa of |tail| */
+			
+			const int64_t negationMask = ((int64_t)(lobits.x)) >> 63;
+			tailMantissa = (tailMantissa ^ negationMask) - negationMask;
+			
+			/* Now we have the mantissa of tail as a signed 2s-complement integer */
+			
+			const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff;
+			
+			/* Shift the tail mantissa into the right position, accounting for the
+			 * bias of 11 that we shifted the head mantissa by.
+			 */
+			tailMantissa >>= (unbiasedHeadExponent - (biasedTailExponent - (1023 - 11)));
+			
+			result += tailMantissa;
+		}
+		
+		result >>= (63 - unbiasedHeadExponent);
+		return result;
+	}
+	
+	/* Edge cases are handled here, with saturation. */
+	if (1.0 > x.s.hi)
+		return UINT64_C(0);
+	else
+		return UINT64_MAX;
+}