mirror of
https://github.com/forth-ev/VolksForth.git
synced 2024-06-26 23:29:28 +00:00
86 lines
5.4 KiB
Plaintext
86 lines
5.4 KiB
Plaintext
Screen 0 not modified
|
|
0 \ ks 22 dez 87
|
|
1 The multitasker is a simple yet powerful round robin scheme
|
|
2 with explicit task switching. This has the major advantage
|
|
3 that the system switches tasks only in known states.
|
|
4 Hence the difficulties in synchronizing tasks and locking
|
|
5 critical portions of code are greatly minimized or simply
|
|
6 do not exist at all.
|
|
7
|
|
8
|
|
9
|
|
10
|
|
11
|
|
12
|
|
13
|
|
14
|
|
15
|
|
Screen 1 not modified
|
|
0 \ Multitasker loadscreen ks 03 apr 88
|
|
1 Onlyforth \needs Assembler 2 loadfrom asm.scr
|
|
2
|
|
3 Code stop $E990 # U ) mov ' pause @ # jmp end-code
|
|
4
|
|
5 : singletask [ ' noop @ ] Literal ['] pause ! ;
|
|
6 : multitask [ ' pause @ ] Literal ['] pause ! ;
|
|
7
|
|
8 1 3 +thru .( Multitasker geladen) cr
|
|
9
|
|
10
|
|
11
|
|
12
|
|
13
|
|
14
|
|
15
|
|
Screen 2 not modified
|
|
0 \ pass activate ks 1 jun 87
|
|
1
|
|
2 : pass ( n0 ... nr-1 Taddr r -- )
|
|
3 BEGIN [ rot ]
|
|
4 swap $E9CD over ! \ awake Task
|
|
5 r> -rot \ Stack: IP r addr
|
|
6 8 + >r \ s0 of Task
|
|
7 r@ 2+ @ swap \ Stack: IP r0 r
|
|
8 2+ 2* \ bytes on Taskstack incl. r0 & IP
|
|
9 r@ @ over - \ new SP
|
|
10 dup r> 2- ! \ into Ssave
|
|
11 swap bounds ?DO I ! 2 +LOOP ; restrict
|
|
12
|
|
13 : activate ( Taddr -- ) 0 \ [ ' pass >body ] Literal >r ;
|
|
14 [ -rot ] REPEAT ; restrict
|
|
15
|
|
Screen 3 not modified
|
|
0 ( Building a Task ks 8 may 84 )
|
|
1
|
|
2 | : taskerror ( string -- ) standardi/o singletask
|
|
3 ." Task error: " count type multitask stop ;
|
|
4
|
|
5 : sleep ( addr -- ) $90 swap c! ;
|
|
6
|
|
7 : wake ( addr -- ) $CD swap c! ;
|
|
8
|
|
9 : rendezvous ( semaphoraddr -- )
|
|
10 dup unlock pause lock ;
|
|
11
|
|
12
|
|
13
|
|
14
|
|
15
|
|
Screen 4 not modified
|
|
0 \ Task ks 1 jun 87
|
|
1
|
|
2 : Task ( rlen slen -- ) clear
|
|
3 0 Constant here 2- >r \ addr of task constant
|
|
4 here -rot \ here for Task dp
|
|
5 even allot even \ allot dictionary area
|
|
6 here r> ! \ set task constant addr
|
|
7 up@ here $100 cmove \ init user area
|
|
8 here $E990 , \ JMP opcode
|
|
9 up@ 2+ dup dup @ + here - ,
|
|
10 2dup - 2- swap ! \ link task
|
|
11 0 , dup 2- dup , , \ ssave and s0
|
|
12 2dup + , \ here + rlen = r0
|
|
13 rot , \ dp
|
|
14 under + dp ! 0 , \ allot rstack
|
|
15 ['] taskerror [ ' errorhandler >body c@ ] Literal rot + ! ;
|