USING: help.markup help.syntax math math.private ;
IN: math.floats

HELP: float
{ $class-description "The class of double-precision floating point numbers." } ;

HELP: >float
{ $values { "x" real } { "y" float } }
{ $description "Converts a real to a float. This is the identity on floats, and performs a floating point division on rationals." } ;

HELP: bits>double ( n -- x )
{ $values { "n" "a 64-bit integer representing an IEEE 754 double-precision float" } { "x" float } }
{ $description "Creates a " { $link float } " object from a 64-bit binary representation. This word is usually used to reconstruct floats read from streams." } ;

{ bits>double bits>float double>bits float>bits } related-words

HELP: bits>float ( n -- x )
{ $values { "n" "a 32-bit integer representing an IEEE 754 single-precision float" } { "x" float } }
{ $description "Creates a " { $link float } " object from a 32-bit binary representation. This word is usually used to reconstruct floats read from streams." } ;

HELP: double>bits ( x -- n )
{ $values { "x" float } { "n" "a 64-bit integer representing an IEEE 754 double-precision float" } }
{ $description "Creates a 64-bit binary representation of a " { $link float } " object. This can be used in the process of writing a float to a stream." } ;

HELP: float>bits ( x -- n )
{ $values { "x" float } { "n" "a 32-bit integer representing an IEEE 754 single-precision float" } }
{ $description "Creates a 32-bit binary representation of a " { $link float } " object. This can be used in the process of writing a float to a stream." } ;

! Unsafe primitives
HELP: float+ ( x y -- z )
{ $values { "x" float } { "y" float } { "z" float } }
{ $description "Primitive version of " { $link + } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link + } " instead." } ;

HELP: float- ( x y -- z )
{ $values { "x" float } { "y" float } { "z" float } }
{ $description "Primitive version of " { $link - } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link - } " instead." } ;

HELP: float* ( x y -- z )
{ $values { "x" float } { "y" float } { "z" float } }
{ $description "Primitive version of " { $link * } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link * } " instead." } ;

HELP: float-mod ( x y -- z )
{ $values { "x" float } { "y" float } { "z" float } }
{ $description "Primitive version of " { $link mod } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link mod } " instead." } ;

HELP: float/f ( x y -- z )
{ $values { "x" float } { "y" float } { "z" float } }
{ $description "Primitive version of " { $link /f } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link /f } " instead." } ;

HELP: float< ( x y -- ? )
{ $values { "x" float } { "y" float } { "?" "a boolean" } }
{ $description "Primitive version of " { $link < } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link < } " instead." } ;

HELP: float<= ( x y -- ? )
{ $values { "x" float } { "y" float } { "?" "a boolean" } }
{ $description "Primitive version of " { $link <= } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link <= } " instead." } ;

HELP: float> ( x y -- ? )
{ $values { "x" float } { "y" float } { "?" "a boolean" } }
{ $description "Primitive version of " { $link > } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link > } " instead." } ;

HELP: float>= ( x y -- ? )
{ $values { "x" float } { "y" float } { "?" "a boolean" } }
{ $description "Primitive version of " { $link >= } "." }
{ $warning "This word does not perform type checking, and passing objects of the wrong type can crash the runtime. User code should call the generic word " { $link >= } " instead." } ;

ARTICLE: "floats" "Floats"
{ $subsection float }
"Rational numbers represent " { $emphasis "exact" } " quantities. On the other hand, a floating point number is an " { $emphasis "approximate" } " value. While rationals can grow to any required precision, floating point numbers have limited precision, and manipulating them is usually faster than manipulating ratios or bignums."
$nl
"Introducing a floating point number in a computation forces the result to be expressed in floating point."
{ $example "5/4 1/2 + ." "1+3/4" }
{ $example "5/4 0.5 + ." "1.75" }
"Integers and rationals can be converted to floats:"
{ $subsection >float }
"Two real numbers can be divided yielding a float result:"
{ $subsection /f }
"Floating point numbers are represented internally in IEEE 754 double-precision format. This internal representation can be accessed for advanced operations and input/output purposes."
{ $subsection float>bits }
{ $subsection double>bits }
{ $subsection bits>float }
{ $subsection bits>double }
"Constructing floating point NaNs:"
{ $subsection <fp-nan> }
"Floating point numbers are discrete:"
{ $subsection prev-float }
{ $subsection next-float }
"Introspection on floating point numbers:"
{ $subsection fp-special? }
{ $subsection fp-nan? }
{ $subsection fp-qnan? }
{ $subsection fp-snan? }
{ $subsection fp-infinity? }
{ $subsection fp-nan-payload }
"Comparing two floating point numbers:"
{ $subsection fp-bitwise= }
{ $see-also "syntax-floats" } ;

ABOUT: "floats"