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Mon Mar 29 22:52:34 1999 UTC (25 years ago) by
crook
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Added section talking about different memory regions, and glossed
associated words. Glossed words associated with user input; the
manual still needs a bunch of examples for these.
\ Number IO
\ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
\ This file is part of Gforth.
\ Gforth is free software; you can redistribute it and/or
\ modify it under the terms of the GNU General Public License
\ as published by the Free Software Foundation; either version 2
\ of the License, or (at your option) any later version.
\ This program is distributed in the hope that it will be useful,
\ but WITHOUT ANY WARRANTY; without even the implied warranty of
\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
\ GNU General Public License for more details.
\ You should have received a copy of the GNU General Public License
\ along with this program; if not, write to the Free Software
\ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
: pad ( -- c-addr ) \ core-ext
\G @var{c-addr} is the address of a transient region that can be
\G used as temporary data storage. At least 84 characters of space
\G is available.
here word-pno-size + aligned ;
\ hold <# #> sign # #s 25jan92py
: hold ( char -- ) \ core
\G Used within @code{<#} and @code{#>}. Append the character
\G @var{char} to the pictured numeric output string.
-1 chars holdptr +!
holdptr @ dup holdbuf u< -&17 and throw
c! ;
: <# ( -- ) \ core less-number-sign
\G Initialise/clear the pictured numeric output string.
holdbuf-end dup holdptr ! holdend ! ;
: #> ( xd -- addr u ) \ core number-sign-greater
\G Complete the pictured numeric output string by
\G discarding xd and returning addr u; the address and length
\G of the formatted string. A Standard program may modify characters
\G within the string.
2drop holdptr @ holdend @ over - ;
: <<# ( -- ) \ gforth less-less-number-sign
\G Start a hold area that ends with @code{#>>}. Can be nested in
\G each other and in @code{<#}. Note: if you do not match up the
\G @code{<<#}s with @code{#>>}s, you will eventually run out of
\G hold area; you can reset the hold area to empty with @code{<#}.
holdend @ holdptr @ - hold
holdptr @ holdend ! ;
: #>> ( -- ) \ gforth number-sign-greater-greater
\G Release the hold area started with @code{<<#}.
holdend @ dup holdbuf-end u>= -&11 and throw
count chars bounds holdptr ! holdend ! ;
: sign ( n -- ) \ core
\G Used within @code{<#} and @code{#>}. If n (a @var{single} number)
\G is negative, append the display code for a minus sign to the pictured
\G numeric output string. Since the string is built up "backwards"
\G this is usually used immediately prior to @code{#>}, as shown in
\G the examples below.
0< IF [char] - hold THEN ;
: # ( ud1 -- ud2 ) \ core number-sign
\G Used within @code{<#} and @code{#>}. Add the next least-significant
\G digit to the pictured numeric output string. This is achieved by dividing ud1
\G by the number in @code{base} to leave quotient ud2 and remainder n; n
\G is converted to the appropriate display code (eg ASCII code) and appended
\G to the string. If the number has been fully converted, ud1 will be 0 and
\G @code{#} will append a "0" to the string.
base @ 2 max ud/mod rot 9 over <
IF
[ char A char 9 - 1- ] Literal +
THEN
[char] 0 + hold ;
: #s ( ud -- 0 0 ) \ core number-sign-s
\G Used within @code{<#} and @code{#>}. Convert all remaining digits
\G using the same algorithm as for @code{#}. @code{#s} will convert
\G at least one digit. Therefore, if ud is 0, @code{#s} will append
\G a "0" to the pictured numeric output string.
BEGIN
# 2dup or 0=
UNTIL ;
\ print numbers 07jun92py
: d.r ( d n -- ) \ double d-dot-r
\G Display @var{d} right-aligned in a field @var{n} characters wide. If more than
\G @var{n} characters are needed to display the number, all digits are displayed.
\G If appropriate, @var{n} must include a character for a leading "-".
>r tuck dabs <<# #s rot sign #>
r> over - spaces type #>> ;
: ud.r ( ud n -- ) \ gforth u-d-dot-r
\G Display @var{ud} right-aligned in a field @var{n} characters wide. If more than
\G @var{n} characters are needed to display the number, all digits are displayed.
>r <<# #s #> r> over - spaces type #>> ;
: .r ( n1 n2 -- ) \ core-ext dot-r
\G Display @var{n1} right-aligned in a field @var{n2} characters wide. If more than
\G @var{n2} characters are needed to display the number, all digits are displayed.
\G If appropriate, @var{n2} must include a character for a leading "-".
>r s>d r> d.r ;
: u.r ( u n -- ) \ core-ext u-dot-r
\G Display @var{u} right-aligned in a field @var{n} characters wide. If more than
\G @var{n} characters are needed to display the number, all digits are displayed.
0 swap ud.r ;
: d. ( d -- ) \ double d-dot
\G Display (the signed double number) @var{d} in free-format. followed by a space.
0 d.r space ;
: ud. ( ud -- ) \ gforth u-d-dot
\G Display (the signed double number) @var{ud} in free-format, followed by a space.
0 ud.r space ;
: . ( n -- ) \ core dot
\G Display (the signed single number) @var{n} in free-format, followed by a space.
s>d d. ;
: u. ( u -- ) \ core u-dot
\G Display (the unsigned single number) @var{u} in free-format, followed by a space.
0 ud. ;
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