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Merge pull request #1208 from denis-sh/std.math.FloatingPointControl-fixes

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`std.math.FloatingPointControl` fixes
This commit is contained in:
David Nadlinger 2013-03-23 14:16:58 -07:00
commit 73aa70f716
1 changed files with 50 additions and 19 deletions
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69
std/math.d
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@ -2778,23 +2778,36 @@ void resetIeeeFlags() { IeeeFlags.resetIeeeFlags(); }
Example:
----
{
----
{
FloatingPointControl fpctrl;
// Enable hardware exceptions for division by zero, overflow to infinity,
// invalid operations, and uninitialized floating-point variables.
FloatingPointControl fpctrl;
fpctrl.enableExceptions(FloatingPointControl.severeExceptions);
double y = x*3.0; // will generate a hardware exception, if x is uninitialized.
//
// 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
// Changing the rounding mode:
fpctrl.rounding = FloatingPointControl.roundUp;
assert(rint(1.1) == 2);
// The hardware exceptions will be disabled when leaving this scope.
// The set hardware exceptions will be disabled when leaving this scope.
// The original rounding mode will also be restored.
}
}
----
// Ensure previous values are returned:
assert(!FloatingPointControl.enabledExceptions);
assert(FloatingPointControl.rounding == FloatingPointControl.roundToNearest);
assert(rint(1.1) == 1);
----
*/
struct FloatingPointControl
@ -2852,8 +2865,8 @@ public:
//// Change the floating-point hardware rounding mode
@property void rounding(RoundingMode newMode)
{
ushort old = getControlState();
setControlState((old & ~ROUNDING_MASK) | (newMode & ROUNDING_MASK));
initialize();
setControlState((getControlState() & ~ROUNDING_MASK) | (newMode & ROUNDING_MASK));
}
/// Return the exceptions which are currently enabled (unmasked)
@ -2872,7 +2885,8 @@ public:
~this()
{
clearExceptions();
setControlState(savedState);
if (initialized)
setControlState(savedState);
}
private:
@ -2963,20 +2977,37 @@ private:
unittest
{
{
void ensureDefaults()
{
assert(FloatingPointControl.rounding
== FloatingPointControl.roundToNearest);
assert(FloatingPointControl.enabledExceptions == 0);
}
{
FloatingPointControl ctrl;
}
ensureDefaults();
{
FloatingPointControl ctrl;
ctrl.rounding = FloatingPointControl.roundDown;
assert(FloatingPointControl.rounding == FloatingPointControl.roundDown);
}
ensureDefaults();
{
FloatingPointControl ctrl;
ctrl.enableExceptions(FloatingPointControl.divByZeroException
| FloatingPointControl.overflowException);
| FloatingPointControl.overflowException);
assert(ctrl.enabledExceptions ==
(FloatingPointControl.divByZeroException
| FloatingPointControl.overflowException));
(FloatingPointControl.divByZeroException
| FloatingPointControl.overflowException));
ctrl.rounding = FloatingPointControl.roundUp;
assert(FloatingPointControl.rounding == FloatingPointControl.roundUp);
}
assert(FloatingPointControl.rounding
== FloatingPointControl.roundToNearest);
assert(FloatingPointControl.enabledExceptions ==0);
ensureDefaults();
}