Import libcompiler_rt into HEAD and add Makefiles.

Obtained from:	user/ed/compiler-rt

1 files changed, 143 insertions, 0 deletions

diff --git a/contrib/compiler-rt/lib/fp_lib.h b/contrib/compiler-rt/lib/fp_lib.h
new file mode 100644
index 0000000..eac670d
--- /dev/null
+++ b/contrib/compiler-rt/lib/fp_lib.h
@@ -0,0 +1,143 @@
+//===-- lib/fp_lib.h - Floating-point utilities -------------------*- C -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a configuration header for soft-float routines in compiler-rt.
+// This file does not provide any part of the compiler-rt interface, but defines
+// many useful constants and utility routines that are used in the
+// implementation of the soft-float routines in compiler-rt.
+//
+// Assumes that float and double correspond to the IEEE-754 binary32 and
+// binary64 types, respectively, and that integer endianness matches floating
+// point endianness on the target platform.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FP_LIB_HEADER
+#define FP_LIB_HEADER
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <limits.h>
+
+#if defined SINGLE_PRECISION
+
+typedef uint32_t rep_t;
+typedef int32_t srep_t;
+typedef float fp_t;
+#define REP_C UINT32_C
+#define significandBits 23
+
+static inline int rep_clz(rep_t a) {
+    return __builtin_clz(a);
+}
+
+// 32x32 --> 64 bit multiply
+static inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) {
+    const uint64_t product = (uint64_t)a*b;
+    *hi = product >> 32;
+    *lo = product;
+}
+
+#elif defined DOUBLE_PRECISION
+
+typedef uint64_t rep_t;
+typedef int64_t srep_t;
+typedef double fp_t;
+#define REP_C UINT64_C
+#define significandBits 52
+
+static inline int rep_clz(rep_t a) {
+#if defined __LP64__
+    return __builtin_clzl(a);
+#else
+    if (a & REP_C(0xffffffff00000000))
+        return __builtin_clz(a >> 32);
+    else 
+        return 32 + __builtin_clz(a & REP_C(0xffffffff));
+#endif
+}
+
+#define loWord(a) (a & 0xffffffffU)
+#define hiWord(a) (a >> 32)
+
+// 64x64 -> 128 wide multiply for platforms that don't have such an operation;
+// many 64-bit platforms have this operation, but they tend to have hardware
+// floating-point, so we don't bother with a special case for them here.
+static inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) {
+    // Each of the component 32x32 -> 64 products
+    const uint64_t plolo = loWord(a) * loWord(b);
+    const uint64_t plohi = loWord(a) * hiWord(b);
+    const uint64_t philo = hiWord(a) * loWord(b);
+    const uint64_t phihi = hiWord(a) * hiWord(b);
+    // Sum terms that contribute to lo in a way that allows us to get the carry
+    const uint64_t r0 = loWord(plolo);
+    const uint64_t r1 = hiWord(plolo) + loWord(plohi) + loWord(philo);
+    *lo = r0 + (r1 << 32);
+    // Sum terms contributing to hi with the carry from lo
+    *hi = hiWord(plohi) + hiWord(philo) + hiWord(r1) + phihi;
+}
+
+#else
+#error Either SINGLE_PRECISION or DOUBLE_PRECISION must be defined.
+#endif
+
+#define typeWidth       (sizeof(rep_t)*CHAR_BIT)
+#define exponentBits    (typeWidth - significandBits - 1)
+#define maxExponent     ((1 << exponentBits) - 1)
+#define exponentBias    (maxExponent >> 1)
+
+#define implicitBit     (REP_C(1) << significandBits)
+#define significandMask (implicitBit - 1U)
+#define signBit         (REP_C(1) << (significandBits + exponentBits))
+#define absMask         (signBit - 1U)
+#define exponentMask    (absMask ^ significandMask)
+#define oneRep          ((rep_t)exponentBias << significandBits)
+#define infRep          exponentMask
+#define quietBit        (implicitBit >> 1)
+#define qnanRep         (exponentMask | quietBit)
+
+static inline rep_t toRep(fp_t x) {
+    const union { fp_t f; rep_t i; } rep = {.f = x};
+    return rep.i;
+}
+
+static inline fp_t fromRep(rep_t x) {
+    const union { fp_t f; rep_t i; } rep = {.i = x};
+    return rep.f;
+}
+
+static inline int normalize(rep_t *significand) {
+    const int shift = rep_clz(*significand) - rep_clz(implicitBit);
+    *significand <<= shift;
+    return 1 - shift;
+}
+
+static inline void wideLeftShift(rep_t *hi, rep_t *lo, int count) {
+    *hi = *hi << count | *lo >> (typeWidth - count);
+    *lo = *lo << count;
+}
+
+static inline void wideRightShiftWithSticky(rep_t *hi, rep_t *lo, int count) {
+    if (count < typeWidth) {
+        const bool sticky = *lo << (typeWidth - count);
+        *lo = *hi << (typeWidth - count) | *lo >> count | sticky;
+        *hi = *hi >> count;
+    }
+    else if (count < 2*typeWidth) {
+        const bool sticky = *hi << (2*typeWidth - count) | *lo;
+        *lo = *hi >> (count - typeWidth) | sticky;
+        *hi = 0;
+    } else {
+        const bool sticky = *hi | *lo;
+        *lo = sticky;
+        *hi = 0;
+    }
+}
+
+#endif // FP_LIB_HEADER