Terminal Task

User Variables

user   ( n "name" -- )         Define a user variable at offset n in the user area
+user  ( n1 n2 n3 "name" -- )  Define a user variable at offset n1 in the user area, and increment the offset 
                               by the size n2 to give a new offset n3.
#user  (  -- n )               Return the number of bytes currently allocated in a user area. 
his    ( addr1 n -- addr2 )    Given a task address addr1 and user variable offset n, returns the address of 
                               the referenced user variable in that task's user area. 

Predefined user variables

base
hook-emit
hook-key
hook-emit?
hook_key?

R0 (R-zero) is the 16-bit address of the bottom of the return stack, which must be in common RAM. R0 is used by ABORT to initialize the S register, which is the return stack pointer. The first value on the stack is stored at the two bytes below R0, and the stack grows downward in memory. After R0 is modified, the new value takes effect after the next ABORT or warm restart.

S0 (S-zero) is the 16-bit address of the bottom of the data stack, which must be in common RAM. S0 is used by ABORT to initialize the Y register, which is the data stack pointer. The first value on the stack is stored at the two bytes below S0, and the stack grows downward in memory. After S0 is modified, the new value takes effect after the next ABORT or warm restart.