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	std.math.hardware
This is a submodule of std.math.
It contains hardware support for floating point numbers.
License: 
Authors: 
Walter Bright, Don Clugston,
           Conversion of CEPHES math library to D by Iain Buclaw and David Nadlinger
Source std/math/hardware.d
- structIeeeFlags;
- IEEE exception status flags ('sticky bits')These flags indicate that an exceptional floating-point condition has occurred. They indicate that a NaN or an infinity has been generated, that a result is inexact, or that a signalling NaN has been encountered. If floating-point exceptions are enabled (unmasked), a hardware exception will be generated instead of setting these flags.Examples:import std.math.traits : isNaN; static void func() { int a = 10 * 10; } real a = 3.5; // Set all the flags to zero resetIeeeFlags(); assert(!ieeeFlags.divByZero); // Perform a division by zero. a /= 0.0L; writeln(a); // real.infinity assert(ieeeFlags.divByZero); // Create a NaN a *= 0.0L; assert(ieeeFlags.invalid); assert(isNaN(a)); // Check that calling func() has no effect on the // status flags. IeeeFlags f = ieeeFlags; func(); writeln(ieeeFlags); // f - nothrow @nogc @property @safe boolinexact() const;
- The result cannot be represented exactly, so rounding occurred.Example x = sin(0.1); 
- nothrow @nogc @property @safe boolunderflow() const;
- A zero was generated by underflowExample x = real.min*real.epsilon/2; 
- nothrow @nogc @property @safe booloverflow() const;
- An infinity was generated by overflowExample x = real.max*2; 
- nothrow @nogc @property @safe booldivByZero() const;
- An infinity was generated by division by zeroExample x = 3/0.0; 
- nothrow @nogc @property @safe boolinvalid() const;
- A machine NaN was generated.Example x = real.infinity * 0.0; 
 
- nothrow @nogc @trusted voidresetIeeeFlags();
- Set all of the floating-point status flags to false.Examples:resetIeeeFlags(); real a = 3.5; a /= 0.0L; writeln(a); // real.infinity assert(ieeeFlags.divByZero); resetIeeeFlags(); assert(!ieeeFlags.divByZero); 
- pure nothrow @nogc @property @trusted IeeeFlagsieeeFlags();
- Returns:snapshot of the current state of the floating-point status flagsExamples:import std.math.traits : isNaN; resetIeeeFlags(); real a = 3.5; a /= 0.0L; writeln(a); // real.infinity assert(ieeeFlags.divByZero); a *= 0.0L; assert(isNaN(a)); assert(ieeeFlags.invalid); 
- structFloatingPointControl;
- Control the Floating point hardwareChange the IEEE754 floating-point rounding mode and the floating-point hardware exceptions. By default, the rounding mode is roundToNearest and all hardware exceptions are disabled. For most applications, debugging is easier if the division by zero, overflow, and invalid operation exceptions are enabled. These three are combined into a severeExceptions value for convenience. Note in particular that if invalidException is enabled, a hardware trap will be generated whenever an uninitialized floating-point variable is used. All changes are temporary. The previous state is restored at the end of the scope.Example { FloatingPointControl fpctrl; // Enable hardware exceptions for division by zero, overflow to infinity, // invalid operations, and uninitialized floating-point variables. fpctrl.enableExceptions(FloatingPointControl.severeExceptions); // This will generate a hardware exception, if x is a // default-initialized floating point variable: real x; // Add `= 0` or even `= real.nan` to not throw the exception. real y = x * 3.0; // The exception is only thrown for default-uninitialized NaN-s. // NaN-s with other payload are valid: real z = y * real.nan; // ok // The set hardware exceptions and rounding modes will be disabled when // leaving this scope. }Examples:import std.math.rounding : lrint; FloatingPointControl fpctrl; fpctrl.rounding = FloatingPointControl.roundDown; writeln(lrint(1.5)); // 1.0 fpctrl.rounding = FloatingPointControl.roundUp; writeln(lrint(1.4)); // 2.0 fpctrl.rounding = FloatingPointControl.roundToNearest; writeln(lrint(1.5)); // 2.0 - aliasRoundingMode= uint;
- roundToNearest- roundDown- roundUp- roundToZero- roundingMask
- IEEE rounding modes. The default mode is roundToNearest.roundingMask = A mask of all rounding modes.
- nothrow @nogc @property @trusted voidrounding(RoundingModenewMode);
- Change the floating-point hardware rounding modeChanging the rounding mode in the middle of a function can interfere with optimizations of floating point expressions, as the optimizer assumes that the rounding mode does not change. It is best to change the rounding mode only at the beginning of the function, and keep it until the function returns. It is also best to add the line:pragma(inline, false); as the first line of the function so it will not get inlined.Parameters:RoundingMode newModethe new rounding mode 
- static pure nothrow @nogc @property @trusted RoundingModerounding();
- Returns:the currently active rounding mode
- aliasExceptionMask= uint;
- subnormalException- inexactException- underflowException- overflowException- divByZeroException- invalidException- severeExceptions- allExceptions
- IEEE hardware exceptions. By default, all exceptions are masked (disabled).severeExceptions = The overflow, division by zero, and invalid exceptions.
- static pure nothrow @nogc @property @safe boolhasExceptionTraps();
- Returns:true if the current FPU supports exception trapping
- nothrow @nogc @trusted voidenableExceptions(ExceptionMaskexceptions);
- Enable (unmask) specific hardware exceptions. Multiple exceptions may be ORed together.
- nothrow @nogc @trusted voiddisableExceptions(ExceptionMaskexceptions);
- Disable (mask) specific hardware exceptions. Multiple exceptions may be ORed together.
- static pure nothrow @nogc @property @trusted ExceptionMaskenabledExceptions();
- Returns:the exceptions which are currently enabled (unmasked)
 
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Ddoc on Mon Mar 31 10:28:20 2025