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fp_extend.h revision 1.1 
      1 //===-lib/fp_extend.h - low precision -> high precision conversion -*- C -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is dual licensed under the MIT and the University of Illinois Open
      6 // Source Licenses. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Set source and destination setting
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef FP_EXTEND_HEADER
     15 #define FP_EXTEND_HEADER
     16 
     17 #include "int_lib.h"
     18 
     19 #if defined SRC_SINGLE
     20 typedef float src_t;
     21 typedef uint32_t src_rep_t;
     22 #define SRC_REP_C UINT32_C
     23 static const int srcSigBits = 23;
     24 #define src_rep_t_clz __builtin_clz
     25 
     26 #elif defined SRC_DOUBLE
     27 typedef double src_t;
     28 typedef uint64_t src_rep_t;
     29 #define SRC_REP_C UINT64_C
     30 static const int srcSigBits = 52;
     31 static inline int src_rep_t_clz(src_rep_t a) {
     32 #if defined __LP64__
     33     return __builtin_clzl(a);
     34 #else
     35     if (a & REP_C(0xffffffff00000000))
     36         return __builtin_clz(a >> 32);
     37     else
     38         return 32 + __builtin_clz(a & REP_C(0xffffffff));
     39 #endif
     40 }
     41 
     42 #else
     43 #error Source should be single precision or double precision!
     44 #endif //end source precision
     45 
     46 #if defined DST_DOUBLE
     47 typedef double dst_t;
     48 typedef uint64_t dst_rep_t;
     49 #define DST_REP_C UINT64_C
     50 static const int dstSigBits = 52;
     51 
     52 #elif defined DST_QUAD
     53 typedef long double dst_t;
     54 typedef __uint128_t dst_rep_t;
     55 #define DST_REP_C (__uint128_t)
     56 static const int dstSigBits = 112;
     57 
     58 #else
     59 #error Destination should be double precision or quad precision!
     60 #endif //end destination precision
     61 
     62 // End of specialization parameters.  Two helper routines for conversion to and
     63 // from the representation of floating-point data as integer values follow.
     64 
     65 static inline src_rep_t srcToRep(src_t x) {
     66     const union { src_t f; src_rep_t i; } rep = {.f = x};
     67     return rep.i;
     68 }
     69 
     70 static inline dst_t dstFromRep(dst_rep_t x) {
     71     const union { dst_t f; dst_rep_t i; } rep = {.i = x};
     72     return rep.f;
     73 }
     74 // End helper routines.  Conversion implementation follows.
     75 
     76 #endif //FP_EXTEND_HEADER
     77