File:  [gforth] / gforth / tasker.fs
Revision 1.8: download - view: text, annotated - select for diffs
Sat Sep 23 15:46:59 2000 UTC (19 years ago) by anton
Branches: MAIN
CVS tags: v0-5-0, HEAD
changed FSF address in copyright messages

    1: \ Multitasker                                          19aug94py
    2: 
    3: \ Copyright (C) 1995,1996,1997 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: Create sleepers  sleepers A, sleepers A, 0 ,
   22: 
   23: \ LINK-TASK links task1 into the task chain of task2
   24: : link-task ( task1 task2 -- )
   25:   over 2@  2dup cell+ ! swap !  \ unlink task1
   26:   2dup @ cell+ !  2dup dup @ rot 2!  ! ;
   27: 
   28: : sleep ( task -- )  sleepers  link-task ;
   29: : wake  ( task -- )  next-task link-task ;
   30: 
   31: \ PAUSE is the task-switcher
   32: : pause ( -- )
   33:   rp@ fp@ lp@ sp@ save-task !
   34:   next-task @ up! save-task @ sp!
   35:   lp! fp! rp! ;
   36: 
   37: \ STOP sleeps a task and switches to the next
   38: : stop ( -- )
   39:   rp@ fp@ lp@ sp@ save-task !
   40:   next-task @ up! save-task @ sp!
   41:   lp! fp! rp! prev-task @ sleep ;
   42: 
   43: \ USER' computes the task offset
   44: :noname    ' >body @ ;
   45: :noname    ' >body @ postpone literal ; 
   46: interpret/compile: user' ( 'user' -- n )
   47: 
   48: \ NEWTASK creates a new, sleeping task
   49: : NewTask ( n -- Task )  dup 2* 2* udp @ + dup
   50:   allocate throw  + >r
   51:   r@ over - udp @ - next-task over udp @ move
   52:   r> over user' rp0 + ! dup >r
   53:   dup r@ user' lp0   + ! over -
   54:   dup r@ user' fp0   + ! over -
   55:   dup r@ user' sp0   + ! over -
   56:   dup r@ user' normal-dp + dup >r !
   57:    r> r@ user' dpp  + ! + $10 +
   58:       r@ user' >tib + !
   59:   r> dup 2dup 2! dup sleep ;
   60: 
   61: : kill-task
   62:   next-task @ up! save-task @ sp!
   63:   lp! fp! rp! prev-task @ dup dup link-task user' normal-dp + @ free throw ;
   64: 
   65: : (pass) ( x1 .. xn n task -- )  rdrop
   66:   [ ' kill-task >body ] ALiteral r>
   67:   rot >r r@ user' rp0 + @ 2 cells - dup >r 2!
   68:   r>              swap 1+
   69:   r@ user' fp0 + @ swap 1+
   70:   r@ user' lp0 + @ swap 1+
   71:   cells r@ user' sp0 + @ tuck swap - dup r@ user' save-task + !
   72:   ?DO  I !  cell  +LOOP  r> wake ;
   73: 
   74: : activate ( task -- )  0 swap (pass) ;
   75: : pass ( x1 .. xn n task -- )  (pass) ;
   76: 
   77: : single-tasking? ( -- flag )
   78:     next-task dup @ = ;
   79: 
   80: : task-key   BEGIN  pause key? single-tasking? or  UNTIL  (key) ;
   81: : task-emit  (emit) pause ;
   82: : task-type  (type) pause ;
   83: 
   84: ' task-key  IS key
   85: ' task-emit IS emit
   86: ' task-type IS type

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