File:  [gforth] / gforth / kernel / basics.fs
Revision 1.37: download - view: text, annotated - select for diffs
Mon Jan 20 17:07:41 2003 UTC (18 years, 10 months ago) by anton
Branches: MAIN
CVS tags: HEAD
undid changes to copyright notices

    1: \ kernel.fs    GForth kernel                        17dec92py
    2: 
    3: \ Copyright (C) 1995,1998,2000 Free Software Foundation, Inc.
    4: 
    5: \ This file is part of Gforth.
    6: 
    7: \ Gforth is free software; you can redistribute it and/or
    8: \ modify it under the terms of the GNU General Public License
    9: \ as published by the Free Software Foundation; either version 2
   10: \ of the License, or (at your option) any later version.
   11: 
   12: \ This program is distributed in the hope that it will be useful,
   13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15: \ GNU General Public License for more details.
   16: 
   17: \ You should have received a copy of the GNU General Public License
   18: \ along with this program; if not, write to the Free Software
   19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
   20: 
   21: \ Idea and implementation: Bernd Paysan (py)
   22: 
   23: \ Needs:
   24: 
   25: require ./vars.fs
   26: require ../compat/strcomp.fs
   27: 
   28: hex
   29: 
   30: \ labels for some code addresses
   31: 
   32: \- NIL NIL AConstant NIL \ gforth
   33: 
   34: \ Aliases
   35: 
   36: [IFUNDEF] r@
   37: ' i Alias r@ ( -- w ; R: w -- w ) \ core r-fetch
   38: [THEN]
   39: 
   40: \ !! this is machine-dependent, but works on all but the strangest machines
   41: 
   42: : maxaligned ( addr1 -- addr2 ) \ gforth
   43:     \G @i{addr2} is the first address after @i{addr1} that satisfies
   44:     \G all alignment restrictions.
   45:     [ /maxalign 1 - ] Literal + [ 0 /maxalign - ] Literal and ;
   46: \ !! machine-dependent and won't work if "0 >body" <> "0 >body
   47:     \G maxaligned"
   48: ' maxaligned Alias cfaligned ( addr1 -- addr2 ) \ gforth
   49: \G @i{addr2} is the first address after @i{addr1} that is aligned for
   50: \G a code field (i.e., such that the corresponding body is maxaligned).
   51: 
   52: : chars ( n1 -- n2 ) \ core
   53: \G @i{n2} is the number of address units of @i{n1} chars.""
   54: ; immediate
   55: 
   56: 
   57: \ : A!    ( addr1 addr2 -- ) \ gforth
   58: \    dup relon ! ;
   59: \ : A,    ( addr -- ) \ gforth
   60: \    here cell allot A! ;
   61: ' ! alias A! ( addr1 addr2 -- ) \ gforth
   62: 
   63: \ UNUSED                                                17may93jaw
   64: 
   65: has? ec 
   66: [IF]
   67: unlock ram-dictionary borders nip lock
   68: AConstant dictionary-end
   69: [ELSE]
   70:     has? header [IF]
   71: 	: dictionary-end ( -- addr )
   72: 	    forthstart [ 3 cells image-header + ] Aliteral @ + ;
   73:     [ELSE]
   74: 	: forthstart 0 ;
   75: 	: dictionary-end ( -- addr )
   76: 	    forthstart [ has? kernel-size ] Literal + ;
   77:     [THEN]
   78: [THEN]
   79: 
   80: : usable-dictionary-end ( -- addr )
   81:     dictionary-end [ word-pno-size pad-minsize + ] Literal - ;
   82: 
   83: : unused ( -- u ) \ core-ext
   84:     \G Return the amount of free space remaining (in address units) in
   85:     \G the region addressed by @code{here}.
   86:     usable-dictionary-end here - ;
   87: 
   88: : in-dictionary? ( x -- f )
   89:     forthstart dictionary-end within ;
   90: 
   91: \ here is used for pad calculation!
   92: 
   93: : dp    ( -- addr ) \ gforth
   94:     dpp @ ;
   95: : here  ( -- addr ) \ core
   96:     \G Return the address of the next free location in data space.
   97:     dp @ ;
   98: 
   99: \ on off                                               23feb93py
  100: 
  101: \ on is used by docol:
  102: : on  ( a-addr -- ) \ gforth
  103:     \G Set the (value of the) variable  at @i{a-addr} to @code{true}.
  104:     true  swap ! ;
  105: : off ( a-addr -- ) \ gforth
  106:     \G Set the (value of the) variable at @i{a-addr} to @code{false}.
  107:     false swap ! ;
  108: 
  109: \ dabs roll                                           17may93jaw
  110: 
  111: : dabs ( d -- ud ) \ double d-abs
  112:     dup 0< IF dnegate THEN ;
  113: 
  114: : roll  ( x0 x1 .. xn n -- x1 .. xn x0 ) \ core-ext
  115:   dup 1+ pick >r
  116:   cells sp@ cell+ dup cell+ rot move drop r> ;
  117: 
  118: \ place bounds                                         13feb93py
  119: 
  120: : place  ( addr len to -- ) \ gforth
  121:     over >r  rot over 1+  r> move c! ;
  122: : bounds ( addr u -- addr+u addr ) \ gforth
  123:     \G Given a memory block represented by starting address @i{addr}
  124:     \G and length @i{u} in aus, produce the end address @i{addr+u} and
  125:     \G the start address in the right order for @code{u+do} or
  126:     \G @code{?do}.
  127:     over + swap ;
  128: 
  129: \ (word)                                               22feb93py
  130: 
  131: : scan   ( addr1 n1 char -- addr2 n2 ) \ gforth
  132:     \ skip all characters not equal to char
  133:     >r
  134:     BEGIN
  135: 	dup
  136:     WHILE
  137: 	over c@ r@ <>
  138:     WHILE
  139: 	1 /string
  140:     REPEAT  THEN
  141:     rdrop ;
  142: : skip   ( addr1 n1 char -- addr2 n2 ) \ gforth
  143:     \ skip all characters equal to char
  144:     >r
  145:     BEGIN
  146: 	dup
  147:     WHILE
  148: 	over c@ r@  =
  149:     WHILE
  150: 	1 /string
  151:     REPEAT  THEN
  152:     rdrop ;
  153: 
  154: \ digit?                                               17dec92py
  155: 
  156: : digit?   ( char -- digit true/ false ) \ gforth
  157:   base @ $100 =
  158:   IF
  159:     true EXIT
  160:   THEN
  161:   toupper [char] 0 - dup 9 u> IF
  162:     [ char A char 9 1 + -  ] literal -
  163:     dup 9 u<= IF
  164:       drop false EXIT
  165:     THEN
  166:   THEN
  167:   dup base @ u>= IF
  168:     drop false EXIT
  169:   THEN
  170:   true ;
  171: 
  172: : accumulate ( +d0 addr digit - +d1 addr )
  173:   swap >r swap  base @  um* drop rot  base @  um* d+ r> ;
  174: 
  175: : >number ( ud1 c-addr1 u1 -- ud2 c-addr2 u2 ) \ core to-number
  176:     \G Attempt to convert the character string @var{c-addr1 u1} to an
  177:     \G unsigned number in the current number base. The double
  178:     \G @var{ud1} accumulates the result of the conversion to form
  179:     \G @var{ud2}. Conversion continues, left-to-right, until the whole
  180:     \G string is converted or a character that is not convertable in
  181:     \G the current number base is encountered (including + or -). For
  182:     \G each convertable character, @var{ud1} is first multiplied by
  183:     \G the value in @code{BASE} and then incremented by the value
  184:     \G represented by the character. @var{c-addr2} is the location of
  185:     \G the first unconverted character (past the end of the string if
  186:     \G the whole string was converted). @var{u2} is the number of
  187:     \G unconverted characters in the string. Overflow is not detected.
  188:     0
  189:     ?DO
  190: 	count digit?
  191:     WHILE
  192: 	accumulate
  193:     LOOP
  194:         0
  195:     ELSE
  196: 	1- I' I -
  197: 	UNLOOP
  198:     THEN ;
  199: 
  200: \ s>d um/mod						21mar93py
  201: 
  202: : s>d ( n -- d ) \ core		s-to-d
  203:     dup 0< ;
  204: 
  205: : ud/mod ( ud1 u2 -- urem udquot ) \ gforth
  206:     >r 0 r@ um/mod r> swap >r
  207:     um/mod r> ;
  208: 
  209: \ catch throw                                          23feb93py
  210: 
  211: has? glocals [IF]
  212: : lp@ ( -- addr ) \ gforth	lp-fetch
  213:  laddr# [ 0 , ] ;
  214: [THEN]
  215: 
  216: defer catch ( x1 .. xn xt -- y1 .. ym 0 / z1 .. zn error ) \ exception
  217: \G @code{Executes} @i{xt}.  If execution returns normally,
  218: \G @code{catch} pushes 0 on the stack.  If execution returns through
  219: \G @code{throw}, all the stacks are reset to the depth on entry to
  220: \G @code{catch}, and the TOS (the @i{xt} position) is replaced with
  221: \G the throw code.
  222: 
  223: :noname ( ... xt -- ... 0 )
  224:     execute 0 ;
  225: is catch
  226: 
  227: defer throw ( y1 .. ym nerror -- y1 .. ym / z1 .. zn error ) \ exception
  228: \G If @i{nerror} is 0, drop it and continue.  Otherwise, transfer
  229: \G control to the next dynamically enclosing exception handler, reset
  230: \G the stacks accordingly, and push @i{nerror}.
  231: 
  232: :noname ( y1 .. ym error -- y1 .. ym / z1 .. zn error )
  233:     ?dup if
  234: 	[ has? header [IF] here image-header 9 cells + ! [THEN] ]
  235: 	cr .error cr
  236: 	[ has? file [IF] ] script? IF  1 (bye)  ELSE  quit  THEN
  237: 	[ [ELSE] ] quit [ [THEN] ]
  238:     then ;
  239: is throw
  240: 
  241: \ (abort")
  242: 
  243: : c(abort") ( c-addr -- )
  244:     "error ! -2 throw ;
  245: 
  246: : (abort")
  247:     "lit >r
  248:     IF
  249: 	r> "error ! -2 throw
  250:     THEN
  251:     rdrop ;
  252: 
  253: : abort ( ?? -- ?? ) \ core,exception-ext
  254:     \G @code{-1 throw}.
  255:     -1 throw ;
  256: 
  257: \ ?stack                                               23feb93py
  258: 
  259: : ?stack ( ?? -- ?? ) \ gforth
  260:     sp@ sp0 @ u> IF    -4 throw  THEN
  261: [ has? floating [IF] ]
  262:     fp@ fp0 @ u> IF  -&45 throw  THEN
  263: [ [THEN] ]
  264: ;
  265: \ ?stack should be code -- it touches an empty stack!
  266: 
  267: \ DEPTH                                                 9may93jaw
  268: 
  269: : depth ( -- +n ) \ core depth
  270:     \G @var{+n} is the number of values that were on the data stack before
  271:     \G @var{+n} itself was placed on the stack.
  272:     sp@ sp0 @ swap - cell / ;
  273: 
  274: : clearstack ( ... -- ) \ gforth clear-stack
  275:     \G remove and discard all/any items from the data stack.
  276:     sp0 @ sp! ;
  277: 
  278: \ Strings						 22feb93py
  279: 
  280: : "lit ( -- addr )
  281:   r> r> dup count + aligned >r swap >r ;
  282: 
  283: \ */MOD */                                              17may93jaw
  284: 
  285: \ !! I think */mod should have the same rounding behaviour as / - anton
  286: : */mod ( n1 n2 n3 -- n4 n5 ) \ core	star-slash-mod
  287:     \G n1*n2=n3*n5+n4, with the intermediate result (n1*n2) being double.
  288:     >r m* r> sm/rem ;
  289: 
  290: : */ ( n1 n2 n3 -- n4 ) \ core	star-slash
  291:     \G n4=(n1*n2)/n3, with the intermediate result being double.
  292:     */mod nip ;
  293: 
  294: \ HEX DECIMAL                                           2may93jaw
  295: 
  296: : decimal ( -- ) \ core
  297:     \G Set @code{base} to &10 (decimal).
  298:     a base ! ;
  299: : hex ( -- ) \ core-ext
  300:     \G Set @code{base} to &16 (hexadecimal).
  301:     10 base ! ;
  302: 

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