Math Namespace Reference

Classes
struct	QuotientRemainder
	Divide one integer by another, rounding towards minus infinity. More...

Functions
constexpr auto	floodRight (std::unsigned_integral auto x) noexcept
	Returns the smallest number of the form 2^n-1 that is greater or equal to the given number.
template<std::signed_integral T>
int16_t	clipToInt16 (T x)
	Clip x to range [-32768,32767].
uint8_t	clipIntToByte (int x)
	Clip x to range [0,255].
constexpr unsigned	reverseNBits (unsigned x, unsigned bits)
	Reverse the lower N bits of a given value.
constexpr uint8_t	reverseByte (uint8_t a)
	Reverse the bits in a byte.
unsigned	findFirstSet (uint32_t x)
	Find the least significant bit that is set.
constexpr float	cubicHermite (std::span< const float, 4 > y, float x)
constexpr QuotientRemainder	div_mod_floor (int dividend, int divisor)
constexpr int	div_floor (int dividend, int divisor)
constexpr int	mod_floor (int dividend, int divisor)

Variables
constexpr double	e = std::numbers::e_v <double>
constexpr double	ln2 = std::numbers::ln2_v <double>
constexpr double	ln10 = std::numbers::ln10_v<double>
constexpr double	pi = std::numbers::pi_v <double>

Function Documentation

clipIntToByte()

uint8_t Math::clipIntToByte ( int  x )

inline

Clip x to range [0,255].

Optimized for the case when no clipping is needed.

Definition at line 61 of file Math.hh.

Referenced by openmsx::VDP::getMSX1Palette(), and TEST_CASE().

clipToInt16()

template<std::signed_integral T>

int16_t Math::clipToInt16 ( T  x )

inline

Clip x to range [-32768,32767].

Optimized for the case when no clipping is needed.

Definition at line 47 of file Math.hh.

Referenced by openmsx::WavImage::getSampleAt(), openmsx::DCFilter::operator()(), TEST_CASE(), and openmsx::Y8950::writeReg().

cubicHermite()

constexpr float Math::cubicHermite ( std::span< const float, 4 >  y, float  x  )

constexpr

Definition at line 167 of file Math.hh.

Referenced by openmsx::WavImage::getSampleAt().

div_floor()

constexpr int Math::div_floor ( int  dividend, int  divisor  )

constexpr

Definition at line 197 of file Math.hh.

References div_mod_floor(), and Math::QuotientRemainder::quotient.

div_mod_floor()

constexpr QuotientRemainder Math::div_mod_floor ( int  dividend, int  divisor  )

constexpr

Definition at line 188 of file Math.hh.

Referenced by div_floor(), mod_floor(), and TEST_CASE().

findFirstSet()

unsigned Math::findFirstSet ( uint32_t  x )

inline

Find the least significant bit that is set.

Returns

0 if the input is zero (no bits are set), otherwise the index of the first set bit + 1.

Definition at line 149 of file Math.hh.

Referenced by openmsx::ColecoJoystickIO::peekIO().

floodRight()

constexpr auto Math::floodRight ( std::unsigned_integral auto  x )

constexprnoexcept

Returns the smallest number of the form 2^n-1 that is greater or equal to the given number.

The resulting number has the same number of leading zeros as the input, but starting from the first 1-bit in the input all bits more to the right are also 1.

Definition at line 32 of file Math.hh.

Referenced by openmsx::VRAMWindow::getReadAreaPlanar(), openmsx::VRAMWindow::isContinuous(), and TEST_CASE().

mod_floor()

constexpr int Math::mod_floor ( int  dividend, int  divisor  )

constexpr

Definition at line 200 of file Math.hh.

References div_mod_floor(), and Math::QuotientRemainder::remainder.

reverseByte()

constexpr uint8_t Math::reverseByte ( uint8_t  a )

constexpr

Reverse the bits in a byte.

This is equivalent to (but faster than) reverseNBits(x, 8);

Definition at line 125 of file Math.hh.

Referenced by openmsx::ImagePrinter::printGraphicByte(), and openmsx::LaserdiscPlayer::serialize().

reverseNBits()

constexpr unsigned Math::reverseNBits ( unsigned  x, unsigned  bits  )

constexpr

Reverse the lower N bits of a given value.

The upper 32-N bits from the input are ignored and will be returned as 0. For example reverseNBits('xxxabcde', 5) returns '000edcba' (binary notation).

Definition at line 75 of file Math.hh.

Referenced by openmsx::LaserdiscPlayer::serialize().

Variable Documentation

e

constexpr double Math::e = std::numbers::e_v <double>

inlineconstexpr

Definition at line 21 of file Math.hh.

Referenced by cstd::exp(), and cstd::log().

ln10

constexpr double Math::ln10 = std::numbers::ln10_v<double>

inlineconstexpr

Definition at line 23 of file Math.hh.

Referenced by cstd::log10().

ln2

constexpr double Math::ln2 = std::numbers::ln2_v <double>

inlineconstexpr

Definition at line 22 of file Math.hh.

Referenced by cstd::exp2(), and cstd::log2().

pi

constexpr double Math::pi = std::numbers::pi_v <double>

inlineconstexpr

Definition at line 24 of file Math.hh.

Referenced by cstd::cos(), gl::degrees(), gl::radians(), openmsx::DCFilter::setFreq(), cstd::sin(), and TEST_CASE().