xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/fp_trunc.h (revision 924226fba12cc9a228c73b956e1b7fa24c60b055)
1 //=== lib/fp_trunc.h - high precision -> low precision conversion *- C -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Set source and destination precision setting
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef FP_TRUNC_HEADER
14 #define FP_TRUNC_HEADER
15 
16 #include "int_lib.h"
17 
18 #if defined SRC_SINGLE
19 typedef float src_t;
20 typedef uint32_t src_rep_t;
21 #define SRC_REP_C UINT32_C
22 static const int srcSigBits = 23;
23 
24 #elif defined SRC_DOUBLE
25 typedef double src_t;
26 typedef uint64_t src_rep_t;
27 #define SRC_REP_C UINT64_C
28 static const int srcSigBits = 52;
29 
30 #elif defined SRC_QUAD
31 typedef long double src_t;
32 typedef __uint128_t src_rep_t;
33 #define SRC_REP_C (__uint128_t)
34 static const int srcSigBits = 112;
35 
36 #else
37 #error Source should be double precision or quad precision!
38 #endif // end source precision
39 
40 #if defined DST_DOUBLE
41 typedef double dst_t;
42 typedef uint64_t dst_rep_t;
43 #define DST_REP_C UINT64_C
44 static const int dstSigBits = 52;
45 
46 #elif defined DST_SINGLE
47 typedef float dst_t;
48 typedef uint32_t dst_rep_t;
49 #define DST_REP_C UINT32_C
50 static const int dstSigBits = 23;
51 
52 #elif defined DST_HALF
53 #ifdef COMPILER_RT_HAS_FLOAT16
54 typedef _Float16 dst_t;
55 #else
56 typedef uint16_t dst_t;
57 #endif
58 typedef uint16_t dst_rep_t;
59 #define DST_REP_C UINT16_C
60 static const int dstSigBits = 10;
61 
62 #else
63 #error Destination should be single precision or double precision!
64 #endif // end destination precision
65 
66 // End of specialization parameters.  Two helper routines for conversion to and
67 // from the representation of floating-point data as integer values follow.
68 
69 static __inline src_rep_t srcToRep(src_t x) {
70   const union {
71     src_t f;
72     src_rep_t i;
73   } rep = {.f = x};
74   return rep.i;
75 }
76 
77 static __inline dst_t dstFromRep(dst_rep_t x) {
78   const union {
79     dst_t f;
80     dst_rep_t i;
81   } rep = {.i = x};
82   return rep.f;
83 }
84 
85 #endif // FP_TRUNC_HEADER
86