"

 COPYRIGHT (c) 1988 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

LimitedPrecisionReal variableByteSubclass:#Float

	instanceVariableNames:''

	classVariableNames:'LastErrorNumber'

	poolDictionaries:''

	category:'Magnitude-Numbers'

!

!Float primitiveDefinitions!

%{

#include <errno.h>

/*

 * on some systems errno is a macro ... check for it here

 */

#ifndef errno

 extern errno;

#endif

%}

! !

!Float class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1988 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    Floats represent rational numbers with limited precision. In ST/X, Float uses

    the underlying C-compilers double implementation, therefore instances of Float

    are usually represented by the 8-byte IEE double precision float format.

    (but there is no guaranty).

    Notice, that Floats are defined as Byte-array to prevent the garbage collector

    from going into the value ... otherwise I needed a special case in many places.

    Also notice, that ST/X Floats are what Doubles are in ST-80 - this may change 

    in one of the next versions (at least on machines, which provide different float

    and double types in their C-compiler.

    WARNING:

    The layout of float instances is known by the runtime system and the compiler;

    you may not add instance variables here. 

    Also, subclassing is complicated by the fact, that the VM creates floats as results

    of arithmetic operations (even if the operands are subclass-instances).

    (It does the float-check by probing a bit in the classes flag instVar).

    Class Variables:

        LastErrorNumber <Integer>       value of errno (after a trig- or other math err)

"

! !

!Float class methodsFor:'instance creation'!

basicNew

    "return a new float - here we return 0.0

     - floats are usually NOT created this way ...

     Its implemented here to allow things like binary store & load

     of floats. (but even this support will go away eventually, its not

     a good idea to store the bits of a float - the reader might have a

     totally different representation - so floats will eventually be 

     binary stored in a device independent format."

%{  /* NOCONTEXT */

    OBJ newFloat;

    __qMKFLOAT(newFloat, 0.0, SENDER);

    RETURN (newFloat);

%}

! !

!Float class methodsFor:'binary storage'!

binaryDefinitionFrom:aStream manager: manager

    |f|

    f := self basicNew.

    self readBinaryIEEEDoubleFrom:aStream into:f.

    ^ f

    "Modified: 16.4.1996 / 21:23:38 / cg"

!

readBinaryIEEEDoubleFrom:aStream

    "read a float from the binary stream, aStream,

     interpreting the next bytes as an IEEE formatted 8-byte float"

    |f|

    f := self basicNew.

    self readBinaryIEEEDoubleFrom:aStream into:f.

    ^ f

    "Created: 16.4.1996 / 20:59:59 / cg"

!

readBinaryIEEEDoubleFrom:aStream into:aFloat

    "read the receivers value from the binary stream, aStream,

     interpreting the next bytes as an IEEE formatted 8-byte float"

    "

     this implementation is wrong: does not work on non-IEEE machines

     (to date all machines where ST/X is running on use

      IEEE float format. Need more here, when porting ST/X to 370's)

    "

    UninterpretedBytes isBigEndian ifFalse:[

	"swap the bytes"

	8 to:1 by:-1 do:[:i |

	    aFloat basicAt:i put:(aStream next)

	].

	^ self

    ].

    1 to:8 do:[:i |

	aFloat basicAt:i put:aStream next

    ]

!

readBinaryIEEESingleFrom:aStream

    "read a float value from the binary stream, aStream,

     interpreting the next bytes as an IEEE formatted 4-byte float"

    |f|

    f := self basicNew.

    self readBinaryIEEESingleFrom:aStream into:f.

    ^ f

    "Created: 16.4.1996 / 21:00:35 / cg"

!

readBinaryIEEESingleFrom:aStream into:aFloat

    "read a float value from the binary stream, aStream,

     interpreting the next bytes as an IEEE formatted 4-byte float"

    "

     this implementation is wrong: does not work on non-IEEE machines

     (to date all machines where ST/X is running on use

      IEEE float format. Need more here, when porting ST/X to 370's)

    "

    UninterpretedBytes isBigEndian ifFalse:[

	"swap the bytes"

	8 to:4 by:-1 do:[:i |

	    aFloat basicAt:i put:(aStream next)

	].

	^ self

    ].

    1 to:4 do:[:i |

	aFloat basicAt:i put:aStream next

    ]

!

storeBinaryIEEEDouble:aFloat on:aStream

    "store aFloat as an IEEE formatted 8-byte float

     onto the binary stream, aStream"

    "

     this implementation is wrong: does not work on non-IEEE machines

     (to date all machines where ST/X is running on use

      IEEE float format. Need more here, when porting ST/X to 370's)

    "

    UninterpretedBytes isBigEndian ifFalse:[

	"swap the bytes"

	8 to:1 by:-1 do:[:i |

	    aStream nextPut:(aFloat basicAt:i).

	].

	^ self

    ].

    1 to:8 do:[:i |

	aStream nextPut:(aFloat basicAt:i).

    ].

!

storeBinaryIEEESingle:aFloat on:aStream

    "store aFloat as an IEEE formatted 4-byte float

     onto the binary stream, aStream"

    "

     this implementation is wrong: does not work on non-IEEE machines

     (to date all machines where ST/X is running on use

      IEEE float format. Need more here, when porting ST/X to 370's)

    "

    UninterpretedBytes isBigEndian ifFalse:[

	"swap the bytes"

	8 to:4 by:-1 do:[:i |

	    aStream nextPut:(aFloat basicAt:i).

	].

	^ self

    ].

    1 to:4 do:[:i |

	aStream nextPut:(aFloat basicAt:i).

    ]

! !

!Float class methodsFor:'constants'!

pi

    "return the constant pi as Float"

    ^ 3.1415926535897932384626434

    "Modified: 23.4.1996 / 09:27:02 / cg"

!

unity

    "return the neutral element for multiplication (1.0) as Float"

    ^ 1.0

    "Modified: 23.4.1996 / 09:27:09 / cg"

!

zero

    "return the neutral element for addition (0.0) as Float"

    ^ 0.0

    "Modified: 23.4.1996 / 09:27:15 / cg"

! !

!Float class methodsFor:'queries'!

isBuiltInClass

    "return true if this class is known by the run-time-system.

     Here, true is returned for myself, false for subclasses."

    ^ self == Float

    "Modified: 23.4.1996 / 15:59:04 / cg"

!

lastErrorNumber

    "return the value of errno after an error"

    ^ LastErrorNumber

    "

     2 arcSin.

     OperatingSystem errorTextForNumber:(Float lastErrorNumber)

    "

! !

!Float methodsFor:'arithmetic'!

* aNumber

    "return the product of the receiver and the argument, aNumber"

%{  /* NOCONTEXT */

    OBJ newFloat;

    double result;

    if (__isSmallInteger(aNumber)) {

	result = __floatVal(self) * (double)(__intVal(aNumber));

retResult:

	__qMKFLOAT(newFloat, result, SENDER);

	RETURN ( newFloat );

    }

    if (__isFloatLike(aNumber)) {

	result = __floatVal(self) * __floatVal(aNumber);

	goto retResult;

    }

%}

.

    ^ aNumber productFromFloat:self

!

+ aNumber

    "return the sum of the receiver and the argument, aNumber"

%{  /* NOCONTEXT */

    OBJ newFloat;

    double result;

    if (__isSmallInteger(aNumber)) {

	result = __floatVal(self) + (double)(__intVal(aNumber));

retResult:

	__qMKFLOAT(newFloat, result, SENDER);

	RETURN ( newFloat );

    }

    if (__isFloatLike(aNumber)) {

	result = __floatVal(self) + __floatVal(aNumber);

	goto retResult;

    }

%}

.

    ^ aNumber sumFromFloat:self

!

- aNumber

    "return the difference of the receiver and the argument, aNumber"

%{  /* NOCONTEXT */

    OBJ newFloat;

    double result;

    if (__isSmallInteger(aNumber)) {

	result = __floatVal(self) - (double)(__intVal(aNumber));

retResult:

	__qMKFLOAT(newFloat, result, SENDER);

	RETURN ( newFloat );

    }

    if (__isFloatLike(aNumber)) {

	result = __floatVal(self) - __floatVal(aNumber);

	goto retResult;

    }

%}

.

    ^ aNumber differenceFromFloat:self

!

/ aNumber

    "return the quotient of the receiver and the argument, aNumber"

%{  /* NOCONTEXT */

    OBJ newFloat;

    double result, val;

    if (__isSmallInteger(aNumber)) {

	if (aNumber != __MKSMALLINT(0)) {

	    result = __floatVal(self) / ( (double)__intVal(aNumber)) ;

retResult:

	    __qMKFLOAT(newFloat, result, SENDER);

	    RETURN ( newFloat );

	}

    } else {

	if (__isFloatLike(aNumber)) {

	    val = __floatVal(aNumber);

	    if (val != 0.0) {

		result = __floatVal(self) / val;

		goto retResult;

	    }

	}

    }

%}

.

    ((aNumber == 0) or:[aNumber = 0.0]) ifTrue:[

	"

	 No, you shalt not divide by zero

	"

	^ DivisionByZeroSignal raise.

    ].

    ^ aNumber quotientFromFloat:self

!

negated

    "return myself negated"

%{  /* NOCONTEXT */

    OBJ newFloat;

    double rslt = - __floatVal(self);

    __qMKFLOAT(newFloat, rslt, SENDER);

    RETURN ( newFloat );

%}

! !

!Float methodsFor:'binary storage'!

storeBinaryDefinitionOn:stream manager:manager

    "store the receiver in a binary format on stream.

     This is an internal interface for binary storage mechanism."

    manager putIdOfClass:(self class) on:stream.

    Float storeBinaryIEEEDouble:self on:stream.

    "Modified: 23.4.1996 / 09:29:48 / cg"

! !

!Float methodsFor:'coercion and converting'!

asFloat

    "return a float with same value - thats me"

    ^ self

!

asInteger

    "return an integer with same value - might truncate"

%{  /* NOCONTEXT */

    if ((__floatVal(self) >= (double)_MIN_INT)

     && (__floatVal(self) <= (double)_MAX_INT)) {

        RETURN ( __MKSMALLINT( (INT)__floatVal(self)) );

    }

%}.

    ^ super asInteger

    "12345.0 asInteger"

    "1e15 asInteger"

!

asShortFloat

    "return a shortFloat with same value as receiver"

%{  /* NOCONTEXT */

    OBJ dummy = @global(ShortFloat);

    OBJ newFloat;

    float fVal = (float)__floatVal(self);

    __qMKSFLOAT(newFloat, fVal, SENDER);

    RETURN ( newFloat );

%}

!

coerce:aNumber

    "return aNumber converted into receivers type"

    ^ aNumber asFloat

!

generality

    "return the generality value - see ArithmeticValue>>retry:coercing:"

    ^ 80

! !

!Float methodsFor:'comparing'!

< aNumber

    "return true, if the argument is greater"

%{  /* NOCONTEXT */

    if (__isSmallInteger(aNumber)) {

	RETURN ( (__floatVal(self) < (double)(__intVal(aNumber))) ? true : false );

    }

    if (__isFloatLike(aNumber)) {

	RETURN ( (__floatVal(self) < __floatVal(aNumber)) ? true : false );

    }

%}

.

    ^ aNumber lessFromFloat:self

!

<= aNumber

    "return true, if the argument is greater or equal"

%{  /* NOCONTEXT */

    if (__isSmallInteger(aNumber)) {

	RETURN ( (__floatVal(self) <= (double)(__intVal(aNumber))) ? true : false );

    }

    if (__isFloatLike(aNumber)) {

	RETURN ( (__floatVal(self) <= __floatVal(aNumber)) ? true : false );

    }

%}

.

    ^ self retry:#<= coercing:aNumber

!

= aNumber

    "return true, if the arguments value are equal by value"

%{  /* NOCONTEXT */

    if (__isSmallInteger(aNumber)) {

	RETURN ( (__floatVal(self) == (double)(__intVal(aNumber))) ? true : false );

    }

    if (__isFloatLike(aNumber)) {

	RETURN ( (__floatVal(self) == __floatVal(aNumber)) ? true : false );

    }

%}