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⌂ ∞ ▽ Elite on the BBC Micro and NES

Text: DETOK3

[BBC Micro disc version, Docked]

       Name: DETOK3                                                  [Show more]
       Type: Subroutine
   Category: Text
    Summary: Print an extended recursive token from the RUTOK token table
  Deep dive: Extended system descriptions
             Extended text tokens

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * PDESC calls DETOK3




 Arguments:

   A                    The recursive token to be printed, in the range 0-255



 Returns:

   A                    A is preserved

   Y                    Y is preserved

   V(1 0)               V(1 0) is preserved



.DETOK3

 PHA                    \ Store A on the stack, so we can retrieve it later

 TAX                    \ Copy the token number from A into X

 TYA                    \ Store Y on the stack
 PHA

 LDA V                  \ Store V(1 0) on the stack
 PHA
 LDA V+1
 PHA

 LDA #LO(RUTOK)         \ Set V to the low byte of RUTOK
 STA V

 LDA #HI(RUTOK)         \ Set A to the high byte of RUTOK

 BNE DTEN               \ Call DTEN to print token number X from the RUTOK
                        \ table and restore the values of A, Y and V(1 0) from
                        \ the stack, returning from the subroutine using a tail
                        \ call (this BNE is effectively a JMP as A is never
                        \ zero)