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