This is a page from DPANS'94, the Draft Proposal on ANS Forth 1994. dpans
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12. The optional Floating-Point word set


12.1 Introduction

See: A.12 The optional Floating-Point word set


12.2 Additional terms and notation


12.2.1 Definition of terms

float-aligned address:
The address of a memory location at which a floating-point number can be accessed.
double-float-aligned address:
The address of a memory location at which a 64-bit IEEE double-precision floating-point number can be accessed.
single-float-aligned address:
The address of a memory location at which a 32-bit IEEE single-precision floating-point number can be accessed.
IEEE floating-point number:
A single- or double-precision floating-point number as defined in ANSI/IEEE 754-1985.


12.2.2 Notation


12.2.2.1 Numeric notation

The following notation is used to define the syntax of the external representation of floating-point numbers:


12.2.2.2 Stack notation

Floating-point stack notation when the floating-point stack is separate from the data stack is:

( F: before -- after )


12.3 Additional usage requirements


12.3.1 Data types

Append table 12.1 to table 3.1.

Table 12.1 - Data Types

Symbol    Data type                       Size on stack
------    ---------                       -------------
r         floating-point number           implementation-defined
f-addr    float-aligned address           1 cell
sf-addr   single-float-aligned address    1 cell
df-addr   double-float-aligned address    1 cell


12.3.1.1 Addresses

The set of float-aligned addresses is an implementation-defined subset of the set of aligned addresses. Adding the size of a floating-point number to a float-aligned address shall produce a float-aligned address.

The set of double-float-aligned addresses is an implementation-defined subset of the set of aligned addresses. Adding the size of a 64-bit IEEE double-precision floating-point number to a double-float-aligned address shall produce a double-float-aligned address.

The set of single-float-aligned addresses is an implementation-defined subset of the set of aligned addresses. Adding the size of a 32-bit IEEE single-precision floating-point number to a single-float-aligned address shall produce a single-float-aligned address.


12.3.1.2 Floating-point numbers

The internal representation of a floating-point number, including the format and precision of the significand and the format and range of the exponent, is implementation defined.

Any rounding or truncation of floating-point numbers is implementation defined.


12.3.2 Floating-point operations

Round to nearest means round the result of a floating-point operation to the representable value nearest the result. If the two nearest representable values are equally near the result, the one having zero as its least significant bit shall be delivered.

Round toward negative infinity means round the result of a floating-point operation to the representable value nearest to and no greater than the result.


12.3.3 Floating-point stack

A last in, first out list that shall be used by all floating-point operators.

The width of the floating-point stack is implementation-defined. By default the floating-point stack shall be separate from the data and return stacks. A program may determine whether floating-point numbers are kept on the data stack by passing the string FLOATING-STACK to ENVIRONMENT?.

The size of a floating-point stack shall be at least 6 items.

A program that depends on the floating-point stack being larger than six items has an environmental dependency.


12.3.4 Environmental queries

Append table 12.2 to table 3.5.

See: 3.2.6 Environmental queries

Table 12.2 - Environmental query strings

String          Value data type  Constant?  Meaning
------          ---------------  ---------  -------
FLOATING        flag             no         floating-point word set present
FLOATING-EXT    flag             no         floating-point extensions word set present
FLOATING-STACK  n                yes        If n = zero, floating-point numbers are 
                                            kept on the data stack; otherwise n is 
                                            the maximum depth of the separate 
                                            floating-point stack.
MAX-FLOAT       r                yes        largest usable floating-point number


12.3.5 Address alignment

Since the address returned by a CREATEd word is not necessarily aligned for any particular class of floating-point data, a program shall align the address (to be float aligned, single-float aligned, or double-float aligned) before accessing floating-point data at the address.

See: 3.3.3.1 Address alignment, A.12.3.5 Address alignment, 12.3.1.1 Addresses.


12.3.6 Variables

A program may address memory in data space regions made available by FVARIABLE. These regions may be non-contiguous with regions subsequently allocated with , (comma) or ALLOT.

See: 3.3.3.3 Variables


12.3.7 Text interpreter input number conversion

If the Floating-Point word set is present in the dictionary and the current base is DECIMAL, the input number-conversion algorithm shall be extended to recognize floating-point numbers in this form:

Convertible string := <significand><exponent>

<significand> := [<sign>]<digits>[.<digits0>]
<exponent>    := E[<sign>]<digits0>
<sign>        := { + | - }
<digits>      := <digit><digits0>
<digits0>     := <digit>*
<digit>       := { 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 }

These are examples of valid representations of floating-point numbers in program source:

        1E   1.E   1.E0   +1.23E-1   -1.23E+1

See: 3.4.1.3 Text interpreter input number conversion, A.12.3.7 Text interpreter input number conversion, 12.6.1.0558 >FLOAT


12.4 Additional documentation requirements


12.4.1 System documentation


12.4.1.1 Implementation-defined options


12.4.1.2 Ambiguous conditions


12.4.1.3 Other system documentation


12.4.2 Program documentation


12.4.2.1 Environmental dependencies


12.4.2.2 Other program documentation


12.5 Compliance and labeling


12.5.1 ANS Forth systems

The phrase Providing the Floating-Point word set shall be appended to the label of any Standard System that provides all of the Floating-Point word set.

The phrase Providing name(s) from the Floating-Point Extensions word set shall be appended to the label of any Standard System that provides portions of the Floating-Point Extensions word set.

The phrase Providing the Floating-Point Extensions word set shall be appended to the label of any Standard System that provides all of the Floating-Point and Floating-Point Extensions word sets.


12.5.2 ANS Forth programs

The phrase Requiring the Floating-Point word set shall be appended to the label of Standard Programs that require the system to provide the Floating-Point word set.

The phrase Requiring name(s) from the Floating-Point Extensions word set shall be appended to the label of Standard Programs that require the system to provide portions of the Floating-Point Extensions word set.

The phrase Requiring the Floating-Point Extensions word set shall be appended to the label of Standard Programs that require the system to provide all of the Floating-Point and Floating-Point Extensions word sets.


12.6 Glossary


12.6.1 Floating-Point words


12.6.1.0558 >FLOAT
to-float FLOATING
        ( c-addr u -- true | false ) ( F: -- r |  )  
        or ( c-addr u -- r true | false)

An attempt is made to convert the string specified by c-addr and u to internal floating-point representation. If the string represents a valid floating-point number in the syntax below, its value r and true are returned. If the string does not represent a valid floating-point number only false is returned.

A string of blanks should be treated as a special case representing zero.

The syntax of a convertible string := <significand>[<exponent>]

<significand> := [<sign>]{<digits>[.<digits0>] |
.<digits> }
<exponent>    := <marker><digits0>
<marker>      := {<e-form> | <sign-form>}
<e-form>      := <e-char>[<sign-form>]
<sign-form>   := { + | - }
<e-char>      := { D | d | E | e }

See: A.12.6.1.0558 >FLOAT


12.6.1.1130 D>F
d-to-f FLOATING
        ( d -- ) ( F: -- r ) 
        or ( d -- r )

r is the floating-point equivalent of d. An ambiguous condition exists if d cannot be precisely represented as a floating-point value.


12.6.1.1400 F!
f-store FLOATING
        ( f-addr -- ) ( F: r -- ) 
        or ( r f-addr -- )

Store r at f-addr.


12.6.1.1410 F*
f-star FLOATING
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

Multiply r1 by r2 giving r3.


12.6.1.1420 F+
f-plus FLOATING
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

Add r1 to r2 giving the sum r3.


12.6.1.1425 F-
f-minus FLOATING
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

Subtract r2 from r1, giving r3.


12.6.1.1430 F/
f-slash FLOATING
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

Divide r1 by r2, giving the quotient r3. An ambiguous condition exists if r2 is zero, or the quotient lies outside of the range of a floating-point number.


12.6.1.1440 F0<
f-zero-less-than FLOATING
        ( -- flag ) ( F: r -- ) 
        or ( r -- flag )

flag is true if and only if r is less than zero.


12.6.1.1450 F0=
f-zero-equals FLOATING
        ( -- flag ) ( F: r -- ) 
        or ( r -- flag )

flag is true if and only if r is equal to zero.


12.6.1.1460 F<
f-less-than FLOATING
        ( -- flag ) ( F: r1 r2 -- ) 
        or ( r1 r2 -- flag )

flag is true

if and only if r1 is less than


12.6.1.1460 F>D
f-to-d FLOATING
        ( -- d ) ( F: r -- ) 
        or ( r -- d )

d is the double-cell signed-integer equivalent of the integer portion of r. The fractional portion of r is discarded. An ambiguous condition exists if the integer portion of r cannot be precisely represented as a double-cell signed integer.


12.6.1.1472 F@
f-fetch FLOATING
        ( f-addr -- ) ( F: -- r )  
        or  ( f-addr -- r )

r is the value stored at f-addr.


12.6.1.1479 FALIGN
f-align FLOATING
        ( -- )

If the data-space pointer is not float aligned, reserve enough data space to make it so.


12.6.1.1483 FALIGNED
f-aligned FLOATING
        ( addr -- f-addr )

f-addr is the first float-aligned address greater than or equal to addr.


12.6.1.1492 FCONSTANT
f-constant FLOATING
        ( "<spaces>name" -- ) ( F: r -- ) 
        or ( r "<spaces>name" -- )

Skip leading space delimiters. Parse name delimited by a space. Create a definition for name with the execution semantics defined below.

name is referred to as an f-constant.

        name Execution: ( -- ) ( F: -- r ) 
                               or ( -- r )

Place r on the floating-point stack.

See: A.12.6.1.1492 FCONSTANT , 3.4.1 Parsing.


12.6.1.1497 FDEPTH
f-depth FLOATING
        ( -- +n )

+n is the number of values contained on the default separate floating-point stack. If floating-point numbers are kept on the data stack, +n is the current number of possible floating-point values contained on the data stack.


12.6.1.1500 FDROP
f-drop
FLOATING
        ( F: r -- ) 
        or ( r -- )

Remove r from the floating-point stack.


12.6.1.1510 FDUP
f-dupe FLOATING
        ( F: r -- r r ) 
        or ( r -- r r )

Duplicate r.


12.6.1.1552 FLITERAL
f-literal FLOATING

        Interpretation: Interpretation semantics for this word are undefined.
        Compilation: ( F: r -- ) 
        or ( r -- )

Append the run-time semantics given below to the current definition.

        Run-time: ( F: -- r ) 
        or ( -- r )

Place r on the floating-point stack.

See: A.12.6.1.1552 FLITERAL


12.6.1.1555 FLOAT+
FLOAT-plus FLOATING
        ( f-addr1 -- f-addr2 )

Add the size in address units of a floating-point number to f-addr1, giving f-addr2.


12.6.1.1556 FLOATS
FLOATING
        ( n1 -- n2 )

n2 is the size in address units of n1 floating-point numbers.


12.6.1.1558 FLOOR
FLOATING
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

Round r1 to an integral value using the round toward negative infinity rule, giving r2.


12.6.1.1562 FMAX
f-max FLOATING
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

r3 is the greater of r1 and r2.


12.6.1.1565 FMIN
f-min FLOATING
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

r3 is the lesser of r1 and r2.


12.6.1.1567 FNEGATE
f-negate FLOATING
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the negation of r1.


12.6.1.1600 FOVER
f-over FLOATING
        ( F: r1 r2 -- r1 r2 r1 ) 
        or ( r1 r2 -- r1 r2 r1 )

Place a copy of r1 on top of the floating-point stack.


12.6.1.1610 FROT
f-rote FLOATING
        ( F: r1 r2 r3 -- r2 r3 r1 ) 
        or ( r1 r2 r3 -- r2 r3 r1 )

Rotate the top three floating-point stack entries.


12.6.1.1612 FROUND
f-round FLOATING
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

Round r1 to an integral value using the round to nearest rule, giving r2.

See: 12.3.2 Floating-point operations


12.6.1.1620 FSWAP
f-swap FLOATING
        ( F: r1 r2 -- r2 r1 ) 
        or ( r1 r2 -- r2 r1 )

Exchange the top two floating-point stack items.


12.6.1.1630 FVARIABLE
f-variable FLOATING
        ( "<spaces>name" -- )

Skip leading space delimiters. Parse name delimited by a space. Create a definition for name with the execution semantics defined below. Reserve 1 FLOATS address units of data space at a float-aligned address.

name is referred to as an f-variable.

        name Execution: ( -- f-addr )

f-addr is the address of the data space reserved by FVARIABLE when it created name. A program is responsible for initializing the contents of the reserved space.

See: A.12.6.1.1630 FVARIABLE , 3.4.1 Parsing.


12.6.1.2143 REPRESENT
FLOATING
        ( c-addr u -- n flag1 flag2 )  (F: r -- )  
        or ( r c-addr u -- n flag1 flag2 )

At c-addr, place the character-string external representation of the significand of the floating-point number r. Return the decimal-base exponent as n, the sign as flag1 and valid result as flag2. The character string shall consist of the u most significant digits of the significand represented as a decimal fraction with the implied decimal point to the left of the first digit, and the first digit zero only if all digits are zero. The significand is rounded to u digits following the round to nearest rule; n is adjusted, if necessary, to correspond to the rounded magnitude of the significand. If flag2 is true then r was in the implementation-defined range of floating-point numbers. If flag1 is true then r is negative.

An ambiguous condition exists if the value of BASE is not decimal ten.

When flag2 is false, n and flag1 are implementation defined, as are the contents of c-addr. Under these circumstances, the string at c-addr shall consist of graphic characters.

See: 3.2.1.2 Digit conversion, 12.3.2 Floating-point operations, A.12.6.1.2143 REPRESENT


12.6.2 Floating-Point extension words


12.6.2.1203 DF!
d-f-store FLOATING EXT
        ( df-addr -- ) ( F: r -- ) 
        or ( r df-addr -- )

Store the floating-point number r as a 64-bit IEEE double-precision number at df-addr. If the significand of the internal representation of r has more precision than the IEEE double-precision format, it will be rounded using the round to nearest rule. An ambiguous condition exists if the exponent of r is too large to be accommodated in IEEE double-precision format.

See: 12.3.1.1 Addresses, 12.3.2 Floating-point operations.


12.6.2.1204 DF@
d-f-fetch FLOATING EXT
        ( df-addr -- ) ( F: -- r ) 
        or ( df-addr -- r )

Fetch the 64-bit IEEE double-precision number stored at df-addr to the floating-point stack as r in the internal representation. If the IEEE double-precision significand has more precision than the internal representation it will be rounded to the internal representation using the round to nearest rule. An ambiguous condition exists if the exponent of the IEEE double-precision representation is too large to be accommodated by the internal representation.

See: 12.3.1.1 Addresses, 12.3.2 Floating-point operations.


12.6.2.1205 DFALIGN
d-f-align FLOATING EXT
        ( -- )

If the data-space pointer is not double-float aligned, reserve enough data space to make it so.

See: 12.3.1.1 Addresses


12.6.2.1207 DFALIGNED
d-f-aligned FLOATING EXT
        ( addr -- df-addr )

df-addr is the first double-float-aligned address greater than or equal to addr.

See: 12.3.1.1 Addresses


12.6.2.1208 DFLOAT+
d-float-plus FLOATING EXT
        ( df-addr1 -- df-addr2 )

Add the size in address units of a 64-bit IEEE double-precision number to df-addr1, giving df-addr2.

See: 12.3.1.1 Addresses


2.6.2.1209 DFLOATS
d-floats FLOATING EXT
        ( n1 -- n2 )

n2 is the size in address units of n1 64-bit IEEE double-precision numbers.


12.6.2.1415 F**
f-star-star FLOATING EXT
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

Raise r1 to the power r2, giving the product r3.


12.6.2.1427 F.
f-dot FLOATING EXT
        ( -- ) ( F: r -- ) 
        or ( r -- )

Display, with a trailing space, the top number on the floating-point stack using fixed-point notation:

        [-] <digits>.<digits0>

An ambiguous condition exists if the value of BASE is not (decimal) ten or if the character string representation exceeds the size of the pictured numeric output string buffer.

See: 12.6.1.0558 >FLOAT , A.12.6.1.1427 F.


12.6.2.1474 FABS
f-abs FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the absolute value of r1.


12.6.2.1476 FACOS
f-a-cos FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the principal radian angle whose cosine is r1. An ambiguous condition exists if |r1| is greater than one.


12.6.2.1477 FACOSH
f-a-cosh FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the floating-point value whose hyperbolic cosine is r1. An ambiguous condition exists if r1 is less than one.


12.6.2.1484 FALOG
f-a-log FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

Raise ten to the power r1, giving r2.


12.6.2.1486 FASIN
f-a-sine FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the principal radian angle whose sine is r1. An ambiguous condition exists if |r1| is greater than one.


12.6.2.1487 FASINH
f-a-cinch FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the floating-point value whose hyperbolic sine is r1. An ambiguous condition exists if r1 is less than zero.


12.6.2.1488 FATAN
f-a-tan FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the principal radian angle whose tangent is r1.


12.6.2.1489 FATAN2
f-a-tan-two FLOATING EXT
        ( F: r1 r2 -- r3 ) 
        or ( r1 r2 -- r3 )

r3 is the radian angle whose tangent is r1/r2. An ambiguous condition exists if r1 and r2 are zero.

See: A.12.6.2.1489 FATAN2


12.6.2.1491 FATANH
f-a-tan-h FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the floating-point value whose hyperbolic tangent is r1. An ambiguous condition exists if r1 is outside the range of -1E0 to 1E0.


12.6.2.1493 FCOS
f-cos FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the cosine of the radian angle r1.


12.6.2.1494 FCOSH
f-cosh FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the hyperbolic cosine of r1.


12.6.2.1513 FE.
f-e-dot FLOATING EXT
        ( -- ) ( F: r -- ) 
        or ( r -- )

Display, with a trailing space, the top number on the floating-point stack using engineering notation, where the significand is greater than or equal to 1.0 and less than 1000.0 and the decimal exponent is a multiple of three.

An ambiguous condition exists if the value of BASE is not (decimal) ten or if the character string representation exceeds the size of the pictured numeric output string buffer.

See: 12.3.2 Floating-point operations, 12.6.1.2143 REPRESENT


12.6.2.1515 FEXP
f-e-x-p FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

Raise e to the power r1, giving r2.


12.6.2.1516 FEXPM1
f-e-x-p-m-one FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

Raise e to the power r1 and subtract one, giving r2.

See: A.12.6.2.1516 FEXPM1


12.6.2.1553 FLN
f-l-n FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the natural logarithm of r1. An ambiguous condition exists if r1 is less than or equal to zero.


12.6.2.1554 FLNP1
f-l-n-p-one FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the natural logarithm of the quantity r1 plus one. An ambiguous condition exists if r1 is less than or equal to negative one.

See: A.12.6.2.1554 FLNP1


12.6.2.1557 FLOG
f-log FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the base-ten logarithm of r1. An ambiguous condition exists if r1 is less than or equal to zero.


12.6.2.1613 FS.
f-s-dot FLOATING EXT
        ( -- ) ( F: r -- ) 
        or ( r -- )

Display, with a trailing space, the top number on the floating-point stack in scientific notation:

        <significand><exponent>

where:

        <significand>  :=  [-]<digit>.<digits0>
        <exponent>     :=  E[-]<digits>

An ambiguous condition exists if the value of BASE is not (decimal) ten or if the character string representation exceeds the size of the pictured numeric output string buffer.

See: 12.3.2 Floating-point operations, 12.6.1.2143 REPRESENT


12.6.2.1614 FSIN
f-sine FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the sine of the radian angle r1.


12.6.2.1616 FSINCOS
f-sine-cos FLOATING EXT
        ( F: r1 -- r2 r3 ) 
        or ( r1 -- r2 r3 )

r2 is the sine of the radian angle r1. r3 is the cosine of the radian angle r1.

See: A.12.6.2.1489 FATAN2


12.6.2.1617 FSINH
f-cinch FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the hyperbolic sine of r1.


12.6.2.1618 FSQRT
f-square-root FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the square root of r1. An ambiguous condition exists if r1 is less than zero.


12.6.2.1625 FTAN
f-tan FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the tangent of the radian angle r1. An ambiguous condition exists if cos(r1) is zero.


12.6.2.1626 FTANH
f-tan-h FLOATING EXT
        ( F: r1 -- r2 ) 
        or ( r1 -- r2 )

r2 is the hyperbolic tangent of r1.


12.6.2.1640 F~
f-proximate FLOATING EXT
(
        ( -- flag ) ( F: r1 r2 r3 -- ) 
        or ( r1 r2 r3 -- flag )

If r3 is positive, flag is true if the absolute value of (r1 minus r2) is less than r3.

If r3 is zero, flag is true if the implementation-dependent encoding of r1 and r2 are exactly identical (positive and negative zero are unequal if they have distinct encodings).

If r3 is negative, flag is true if the absolute value of (r1 minus r2) is less than the absolute value of r3 times the sum of the absolute values of r1 and r2.

See: A.12.6.2.1640 F~


12.6.2.2035 PRECISION
FLOATING EXT
        ( -- u )

Return the number of significant digits currently used by F., FE., or FS. as u.


12.6.2.2200 SET-PRECISION
FLOATING EXT
        ( u -- )

Set the number of significant digits currently used by F., FE., or FS. to u.


12.6.2.2202 SF!
s-f-store FLOATING EXT
        ( sf-addr -- ) ( F: r -- ) 
        or ( r sf-addr -- )

Store the floating-point number r as a 32-bit IEEE single-precision number at sf-addr. If the significand of the internal representation of r has more precision than the IEEE single-precision format, it will be rounded using the round to nearest rule. An ambiguous condition exists if the exponent of r is too large to be accommodated by the IEEE single-precision format.

See: 12.3.1.1 Addresses, 12.3.2 Floating-point operations.


12.6.2.2203 SF@
s-f-fetch FLOATING EXT
        ( sf-addr -- ) ( F: -- r ) 
        or ( sf-addr -- r )

Fetch the 32-bit IEEE single-precision number stored at sf-addr to the floating-point stack as r in the internal representation. If the IEEE single-precision significand has more precision than the internal representation, it will be rounded to the internal representation using the round to nearest rule. An ambiguous condition exists if the exponent of the IEEE single-precision representation is too large to be accommodated by the internal representation.

See: 12.3.1.1 Addresses, 12.3.2 Floating-point operations.


12.6.2.2204 SFALIGN
s-f-align FLOATING EXT
        ( -- )

If the data-space pointer is not single-float aligned, reserve enough data space to make it so.

See: 12.3.1.1 Addresses


12.6.2.2206 SFALIGNED
s-f-aligned FLOATING EXT
        ( addr -- sf-addr )

sf-addr is the first single-float-aligned address greater than or equal to addr.

See: 12.3.1.1 Addresses


12.6.2.2207 SFLOAT+
s-float-plus FLOATING EXT
        ( sf-addr1 -- sf-addr2 )

Add the size in address units of a 32-bit IEEE single-precision number to sf-addr1, giving sf-addr2.

See: 12.3.1.1 Addresses


12.6.2.2208 SFLOATS
s-floats FLOATING EXT
        ( n1 -- n2 )

n2 is the size in address units of n1 32-bit IEEE single-precision numbers.

See: 12.3.1.1 Addresses


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