Adding tasks.

ueforth/Makefile

@@ -71,7 +71,8 @@ $(GEN):
 
 POSIX_BOOT =  common/boot.fs common/terminal.fs \
               posix/posix.fs posix/posix_highlevel.fs \
-              common/filetools.fs posix/posix_desktop.fs
+              common/filetools.fs posix/posix_desktop.fs \
+              common/tasks.fs
 $(GEN)/posix_boot.h: common/source_to_string.js $(POSIX_BOOT) | $(GEN)
 	echo "ok" | cat $(POSIX_BOOT) - | $< boot >$@
 
@@ -81,7 +82,7 @@ $(GEN)/windows_boot.h: common/source_to_string.js $(WINDOWS_BOOT) | $(GEN)
 
 ARDUINO_BOOT = common/boot.fs arduino/arduino.fs \
                posix/posix_highlevel.fs common/filetools.fs \
-               arduino/arduino_server.fs \
+               common/tasks.fs arduino/arduino_server.fs \
                arduino/autoboot.fs
 $(GEN)/arduino_boot.h: common/source_to_string.js $(ARDUINO_BOOT) | $(GEN)
 	echo "ok" | cat $(ARDUINO_BOOT) - | $< boot >$@

ueforth/common/tasks.fs

@@ -0,0 +1,30 @@
+( Cooperative Tasks )
+
+variable task-list
+
+: add-task ( t -- )
+   task-list @ if
+     task-list @ @ over !
+     task-list @ !
+   else
+     dup task-list !
+     dup !
+   then
+;
+
+: task ( xt rsz dsz "name" )
+   create here >r 0 , 0 , 0 ,
+   here cell+ r@ cell+ ! cells allot
+   here r@ 2 cells + ! cells allot
+   dup 0= if drop else >:body r@ 2 cells + @ ! then
+   r> add-task ;
+
+: pause
+  rp@ task-list @ 2 cells + !
+  sp@ task-list @ cell+ !
+  task-list @ @ task-list !
+  task-list @ cell+ @ sp!
+  task-list @ 2 cells + @ rp!
+;
+
+0 0 0 task main-task

ueforth/posix/posix.fs

@@ -32,6 +32,7 @@ z" rename" 2 sysfunc rename
 z" malloc" 1 sysfunc malloc
 z" free" 1 sysfunc sysfree
 z" realloc" 2 sysfunc realloc
+z" usleep" 1 sysfunc usleep
 
 ( Errno )
 z" __errno_location" 0 sysfunc __errno_location
@@ -95,3 +96,6 @@ octal 777 constant 0777 decimal
    dup 0 SEEK_CUR lseek >r
    dup 0 SEEK_END lseek r> swap >r
          SEEK_SET lseek drop r> 0<ior ;
+
+( Other Utils )
+: ms ( n -- ) 1000 * usleep drop ;