1// Copyright 2010 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_CACHED_POWERS_H_
6#define V8_CACHED_POWERS_H_
7
8#include "src/base/logging.h"
9#include "src/diy-fp.h"
10
11namespace v8 {
12namespace internal {
13
14class PowersOfTenCache {
15 public:
16 // Not all powers of ten are cached. The decimal exponent of two neighboring
17 // cached numbers will differ by kDecimalExponentDistance.
18 static const int kDecimalExponentDistance;
19
20 static const int kMinDecimalExponent;
21 static const int kMaxDecimalExponent;
22
23 // Returns a cached power-of-ten with a binary exponent in the range
24 // [min_exponent; max_exponent] (boundaries included).
25 static void GetCachedPowerForBinaryExponentRange(int min_exponent,
26 int max_exponent,
27 DiyFp* power,
28 int* decimal_exponent);
29
30 // Returns a cached power of ten x ~= 10^k such that
31 // k <= decimal_exponent < k + kCachedPowersDecimalDistance.
32 // The given decimal_exponent must satisfy
33 // kMinDecimalExponent <= requested_exponent, and
34 // requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance.
35 static void GetCachedPowerForDecimalExponent(int requested_exponent,
36 DiyFp* power,
37 int* found_exponent);
38};
39
40} // namespace internal
41} // namespace v8
42
43#endif // V8_CACHED_POWERS_H_
44