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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 "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((x << 10 >> 10) == x); return x << 10; } #define SkScalarToFDot6(x) (SkFDot6)((x) * 64) #define SkFDot6ToScalar(x) ((SkScalar)(x) * 0.015625f) inline SkFixed SkFDot6Div(SkFDot6 a, SkFDot6 b) { SkASSERT(b != 0); if (a == (int16_t)a) { return (a << 16) / b; } else { return SkFixedDiv(a, b); } } #endif