vendor/compiler-rt/compiler-rt-r224034

1 files changed, 53 insertions, 0 deletions

diff --git a/lib/builtins/floatsidf.c b/lib/builtins/floatsidf.c
new file mode 100644
index 000000000000..1cf99b782a60
--- /dev/null
+++ b/lib/builtins/floatsidf.c
@@ -0,0 +1,53 @@
+//===-- lib/floatsidf.c - integer -> double-precision conversion --*- C -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements integer to double-precision conversion for the
+// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
+// mode.
+//
+//===----------------------------------------------------------------------===//
+
+#define DOUBLE_PRECISION
+#include "fp_lib.h"
+
+#include "int_lib.h"
+
+ARM_EABI_FNALIAS(i2d, floatsidf)
+
+COMPILER_RT_ABI fp_t
+__floatsidf(int a) {
+    
+    const int aWidth = sizeof a * CHAR_BIT;
+    
+    // Handle zero as a special case to protect clz
+    if (a == 0)
+        return fromRep(0);
+    
+    // All other cases begin by extracting the sign and absolute value of a
+    rep_t sign = 0;
+    if (a < 0) {
+        sign = signBit;
+        a = -a;
+    }
+    
+    // Exponent of (fp_t)a is the width of abs(a).
+    const int exponent = (aWidth - 1) - __builtin_clz(a);
+    rep_t result;
+    
+    // Shift a into the significand field and clear the implicit bit.  Extra
+    // cast to unsigned int is necessary to get the correct behavior for
+    // the input INT_MIN.
+    const int shift = significandBits - exponent;
+    result = (rep_t)(unsigned int)a << shift ^ implicitBit;
+    
+    // Insert the exponent
+    result += (rep_t)(exponent + exponentBias) << significandBits;
+    // Insert the sign bit and return
+    return fromRep(result | sign);
+}