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dtoa.cc
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27 
28 #include <cmath>
29 
30 #include "../include/v8stdint.h"
31 #include "checks.h"
32 #include "utils.h"
33 
34 #include "dtoa.h"
35 
36 #include "bignum-dtoa.h"
37 #include "double.h"
38 #include "fast-dtoa.h"
39 #include "fixed-dtoa.h"
40 
41 namespace v8 {
42 namespace internal {
43 
44 static BignumDtoaMode DtoaToBignumDtoaMode(DtoaMode dtoa_mode) {
45  switch (dtoa_mode) {
47  case DTOA_FIXED: return BIGNUM_DTOA_FIXED;
49  default:
50  UNREACHABLE();
51  return BIGNUM_DTOA_SHORTEST; // To silence compiler.
52  }
53 }
54 
55 
56 void DoubleToAscii(double v, DtoaMode mode, int requested_digits,
57  Vector<char> buffer, int* sign, int* length, int* point) {
58  ASSERT(!Double(v).IsSpecial());
59  ASSERT(mode == DTOA_SHORTEST || requested_digits >= 0);
60 
61  if (Double(v).Sign() < 0) {
62  *sign = 1;
63  v = -v;
64  } else {
65  *sign = 0;
66  }
67 
68  if (v == 0) {
69  buffer[0] = '0';
70  buffer[1] = '\0';
71  *length = 1;
72  *point = 1;
73  return;
74  }
75 
76  if (mode == DTOA_PRECISION && requested_digits == 0) {
77  buffer[0] = '\0';
78  *length = 0;
79  return;
80  }
81 
82  bool fast_worked;
83  switch (mode) {
84  case DTOA_SHORTEST:
85  fast_worked = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, length, point);
86  break;
87  case DTOA_FIXED:
88  fast_worked = FastFixedDtoa(v, requested_digits, buffer, length, point);
89  break;
90  case DTOA_PRECISION:
91  fast_worked = FastDtoa(v, FAST_DTOA_PRECISION, requested_digits,
92  buffer, length, point);
93  break;
94  default:
95  UNREACHABLE();
96  fast_worked = false;
97  }
98  if (fast_worked) return;
99 
100  // If the fast dtoa didn't succeed use the slower bignum version.
101  BignumDtoaMode bignum_mode = DtoaToBignumDtoaMode(mode);
102  BignumDtoa(v, bignum_mode, requested_digits, buffer, length, point);
103  buffer[*length] = '\0';
104 }
105 
106 } } // namespace v8::internal
#define ASSERT(condition)
Definition: checks.h:329
#define UNREACHABLE()
Definition: checks.h:52
enable upcoming ES6 features enable harmony block scoping enable harmony enable harmony proxies enable harmony generators enable harmony numeric enable harmony string enable harmony math functions harmony_scoping harmony_symbols harmony_collections harmony_iteration harmony_strings harmony_scoping harmony_maths tracks arrays with only smi values Optimize object Array DOM strings and string pretenure call new trace pretenuring decisions of HAllocate instructions track fields with only smi values track fields with heap values track_fields track_fields Enables optimizations which favor memory size over execution speed use string slices optimization filter maximum number of GVN fix point iterations use function inlining use allocation folding eliminate write barriers targeting allocations in optimized code maximum source size in bytes considered for a single inlining maximum cumulative number of AST nodes considered for inlining crankshaft harvests type feedback from stub cache trace check elimination phase hydrogen tracing filter trace hydrogen to given file name trace inlining decisions trace store elimination trace all use positions trace global value numbering trace hydrogen escape analysis trace the tracking of allocation sites trace map generalization environment for every instruction deoptimize every n garbage collections put a break point before deoptimizing deoptimize uncommon cases use on stack replacement trace array bounds check elimination perform array index dehoisting use load elimination use store elimination use constant folding eliminate unreachable code number of stress runs when picking a function to watch for shared function not JSFunction itself flushes the cache of optimized code for closures on every GC functions with arguments object maximum number of escape analysis fix point iterations allow uint32 values on optimize frames if they are used only in safe operations track concurrent recompilation artificial compilation delay in ms concurrent on stack replacement do not emit check maps for constant values that have a leaf deoptimize the optimized code if the layout of the maps changes number of stack frames inspected by the profiler percentage of ICs that must have type info to allow optimization extra verbose compilation tracing generate extra emit comments in code disassembly enable use of SSE3 instructions if available enable use of CMOV instruction if available enable use of VFP3 instructions if available enable use of NEON instructions if enable use of SDIV and UDIV instructions if enable loading bit constant by means of movw movt instruction enable unaligned accesses for enable use of d16 d31 registers on ARM this requires VFP3 force all emitted branches to be in long mode(MIPS only)") DEFINE_string(expose_natives_as
void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits, Vector< char > buffer, int *length, int *decimal_point)
Definition: bignum-dtoa.cc:92
bool FastDtoa(double v, FastDtoaMode mode, int requested_digits, Vector< char > buffer, int *length, int *decimal_point)
Definition: fast-dtoa.cc:709
bool FastFixedDtoa(double v, int fractional_count, Vector< char > buffer, int *length, int *decimal_point)
Definition: fixed-dtoa.cc:312
void DoubleToAscii(double v, DtoaMode mode, int requested_digits, Vector< char > buffer, int *sign, int *length, int *point)
Definition: dtoa.cc:56