1 files changed, 50 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/ppc/gcc_qmul.c b/contrib/llvm-project/compiler-rt/lib/builtins/ppc/gcc_qmul.c
new file mode 100644
index 000000000000..75f519aad6f0
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/builtins/ppc/gcc_qmul.c
@@ -0,0 +1,50 @@
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// long double __gcc_qmul(long double x, long double y);
+// This file implements the PowerPC 128-bit double-double multiply operation.
+// This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
+
+#include "DD.h"
+
+long double __gcc_qmul(long double x, long double y) {
+  static const uint32_t infinityHi = UINT32_C(0x7ff00000);
+  DD dst = {.ld = x}, src = {.ld = y};
+
+  register double A = dst.s.hi, a = dst.s.lo, B = src.s.hi, b = src.s.lo;
+
+  double aHi, aLo, bHi, bLo;
+  double ab, tmp, tau;
+
+  ab = A * B;
+
+  // Detect special cases
+  if (ab == 0.0) {
+    dst.s.hi = ab;
+    dst.s.lo = 0.0;
+    return dst.ld;
+  }
+
+  const doublebits abBits = {.d = ab};
+  if (((uint32_t)(abBits.x >> 32) & infinityHi) == infinityHi) {
+    dst.s.hi = ab;
+    dst.s.lo = 0.0;
+    return dst.ld;
+  }
+
+  // Generic cases handled here.
+  aHi = high26bits(A);
+  bHi = high26bits(B);
+  aLo = A - aHi;
+  bLo = B - bHi;
+
+  tmp = LOWORDER(ab, aHi, aLo, bHi, bLo);
+  tmp += (A * b + a * B);
+  tau = ab + tmp;
+
+  dst.s.lo = (ab - tau) + tmp;
+  dst.s.hi = tau;
+
+  return dst.ld;
+}