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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkFDot6_DEFINED
#define SkFDot6_DEFINED
#include "SkFixed.h"
#include "SkScalar.h"
#include "SkMath.h"
typedef int32_t SkFDot6;
/* This uses the magic number approach suggested here:
* http://stereopsis.com/sree/fpu2006.html and used in
* _cairo_fixed_from_double. It does banker's rounding
* (i.e. round to nearest even)
*/
inline SkFDot6 SkScalarRoundToFDot6(SkScalar x, int shift = 0)
{
union {
double fDouble;
int32_t fBits[2];
} tmp;
int fractionalBits = 6 + shift;
double magic = (1LL << (52 - (fractionalBits))) * 1.5;
tmp.fDouble = SkScalarToDouble(x) + magic;
#ifdef SK_CPU_BENDIAN
return tmp.fBits[1];
#else
return tmp.fBits[0];
#endif
}
#define SK_FDot6One (64)
#define SK_FDot6Half (32)
#ifdef SK_DEBUG
inline SkFDot6 SkIntToFDot6(S16CPU x) {
SkASSERT(SkToS16(x) == x);
return x << 6;
}
#else
#define SkIntToFDot6(x) ((x) << 6)
#endif
#define SkFDot6Floor(x) ((x) >> 6)
#define SkFDot6Ceil(x) (((x) + 63) >> 6)
#define SkFDot6Round(x) (((x) + 32) >> 6)
#define SkFixedToFDot6(x) ((x) >> 10)
inline SkFixed SkFDot6ToFixed(SkFDot6 x) {
SkASSERT((SkLeftShift(x, 10) >> 10) == x);
return SkLeftShift(x, 10);
}
#define SkScalarToFDot6(x) (SkFDot6)((x) * 64)
#define SkFDot6ToScalar(x) ((SkScalar)(x) * 0.015625f)
#define SkFDot6ToFloat SkFDot6ToScalar
inline SkFixed SkFDot6Div(SkFDot6 a, SkFDot6 b) {
SkASSERT(b != 0);
if (a == (int16_t)a) {
return SkLeftShift(a, 16) / b;
} else {
return SkFixedDiv(a, b);
}
}
#endif
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