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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 SkFixed_DEFINED
#define SkFixed_DEFINED
#include "SkScalar.h"
#include "SkTypes.h"
/** \file SkFixed.h
Types and macros for 16.16 fixed point
*/
/** 32 bit signed integer used to represent fractions values with 16 bits to the right of the decimal point
*/
typedef int32_t SkFixed;
#define SK_Fixed1 (1 << 16)
#define SK_FixedHalf (1 << 15)
#define SK_FixedMax (0x7FFFFFFF)
#define SK_FixedMin (-SK_FixedMax)
#define SK_FixedPI (0x3243F)
#define SK_FixedSqrt2 (92682)
#define SK_FixedTanPIOver8 (0x6A0A)
#define SK_FixedRoot2Over2 (0xB505)
#define SkFixedToFloat(x) ((x) * 1.52587890625e-5f)
#if 1
#define SkFloatToFixed(x) ((SkFixed)((x) * SK_Fixed1))
#else
// pins over/under flows to max/min int32 (slower than just a cast)
static inline SkFixed SkFloatToFixed(float x) {
int64_t n = x * SK_Fixed1;
return (SkFixed)n;
}
#endif
#ifdef SK_DEBUG
static inline SkFixed SkFloatToFixed_Check(float x) {
int64_t n64 = (int64_t)(x * SK_Fixed1);
SkFixed n32 = (SkFixed)n64;
SkASSERT(n64 == n32);
return n32;
}
#else
#define SkFloatToFixed_Check(x) SkFloatToFixed(x)
#endif
#define SkFixedToDouble(x) ((x) * 1.52587890625e-5)
#define SkDoubleToFixed(x) ((SkFixed)((x) * SK_Fixed1))
/** Converts an integer to a SkFixed, asserting that the result does not overflow
a 32 bit signed integer
*/
#ifdef SK_DEBUG
inline SkFixed SkIntToFixed(int n)
{
SkASSERT(n >= -32768 && n <= 32767);
// Left shifting a negative value has undefined behavior in C, so we cast to unsigned before
// shifting.
return (unsigned)n << 16;
}
#else
// Left shifting a negative value has undefined behavior in C, so we cast to unsigned before
// shifting. Then we force the cast to SkFixed to ensure that the answer is signed (like the
// debug version).
#define SkIntToFixed(n) (SkFixed)((unsigned)(n) << 16)
#endif
#define SkFixedRoundToInt(x) (((x) + SK_FixedHalf) >> 16)
#define SkFixedCeilToInt(x) (((x) + SK_Fixed1 - 1) >> 16)
#define SkFixedFloorToInt(x) ((x) >> 16)
#define SkFixedRoundToFixed(x) (((x) + SK_FixedHalf) & 0xFFFF0000)
#define SkFixedCeilToFixed(x) (((x) + SK_Fixed1 - 1) & 0xFFFF0000)
#define SkFixedFloorToFixed(x) ((x) & 0xFFFF0000)
#define SkFixedAbs(x) SkAbs32(x)
#define SkFixedAve(a, b) (((a) + (b)) >> 1)
// Blink layout tests are baselined to Clang optimizing through undefined behavior in SkDivBits.
#if defined(SK_SUPPORT_LEGACY_DIVBITS_UB)
#define SkFixedDiv(numer, denom) SkDivBits(numer, denom, 16)
#else
// The divide may exceed 32 bits. Clamp to a signed 32 bit result.
#define SkFixedDiv(numer, denom) \
SkToS32(SkTPin<int64_t>((SkLeftShift((int64_t)numer, 16) / denom), SK_MinS32, SK_MaxS32))
#endif
//////////////////////////////////////////////////////////////////////////////////////////////////////
// Now look for ASM overrides for our portable versions (should consider putting this in its own file)
inline SkFixed SkFixedMul_longlong(SkFixed a, SkFixed b) {
return (SkFixed)((int64_t)a * b >> 16);
}
#define SkFixedMul(a,b) SkFixedMul_longlong(a,b)
#if defined(SK_CPU_ARM32)
/* This guy does not handle NaN or other obscurities, but is faster than
than (int)(x*65536). When built on Android with -Os, needs forcing
to inline or we lose the speed benefit.
*/
SK_ALWAYS_INLINE SkFixed SkFloatToFixed_arm(float x)
{
int32_t y, z;
asm("movs %1, %3, lsl #1 \n"
"mov %2, #0x8E \n"
"sub %1, %2, %1, lsr #24 \n"
"mov %2, %3, lsl #8 \n"
"orr %2, %2, #0x80000000 \n"
"mov %1, %2, lsr %1 \n"
"it cs \n"
"rsbcs %1, %1, #0 \n"
: "=r"(x), "=&r"(y), "=&r"(z)
: "r"(x)
: "cc"
);
return y;
}
inline SkFixed SkFixedMul_arm(SkFixed x, SkFixed y)
{
int32_t t;
asm("smull %0, %2, %1, %3 \n"
"mov %0, %0, lsr #16 \n"
"orr %0, %0, %2, lsl #16 \n"
: "=r"(x), "=&r"(y), "=r"(t)
: "r"(x), "1"(y)
:
);
return x;
}
#undef SkFixedMul
#define SkFixedMul(x, y) SkFixedMul_arm(x, y)
#undef SkFloatToFixed
#define SkFloatToFixed(x) SkFloatToFixed_arm(x)
#endif
///////////////////////////////////////////////////////////////////////////////
#if SK_SCALAR_IS_FLOAT
#define SkFixedToScalar(x) SkFixedToFloat(x)
#define SkScalarToFixed(x) SkFloatToFixed(x)
#else // SK_SCALAR_IS_DOUBLE
#define SkFixedToScalar(x) SkFixedToDouble(x)
#define SkScalarToFixed(x) SkDoubleToFixed(x)
#endif
///////////////////////////////////////////////////////////////////////////////
typedef int64_t SkFixed3232; // 32.32
#define SkIntToFixed3232(x) (SkLeftShift((SkFixed3232)(x), 32))
#define SkFixed3232ToInt(x) ((int)((x) >> 32))
#define SkFixedToFixed3232(x) (SkLeftShift((SkFixed3232)(x), 16))
#define SkFixed3232ToFixed(x) ((SkFixed)((x) >> 16))
#define SkFloatToFixed3232(x) ((SkFixed3232)((x) * (65536.0f * 65536.0f)))
#define SkScalarToFixed3232(x) SkFloatToFixed3232(x)
#endif
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