The SwitchToCharSet (Encyclopedia) subroutine - Elite on the BBC Micro and NES

       Name: SwitchToCharSet                                         [Show more]
       Type: Subroutine
   Category: Utility routines
    Summary: Switch the MOS character definitions into memory at &C000 on a BBC
             Master
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * DOENTRY calls SwitchToCharSet


                        \ --- Mod: Code added for Elite-A: -------------------->

IF _BUG_FIX

.SwitchToCharSet

                        \ This routine switches the MOS character definitions
                        \ into memory at &C000 on a BBC Master

 LDA #0                 \ Call OSBYTE with A = 0 and X = 1 to fetch bit 0 of the
 LDX #1                 \ operating system version into X
 JSR OSBYTE

 CPX #3                 \ If X =< 3 then this is not a BBC Master, so jump to
 BCC char1              \ char1 to continue drawing the character

 JSR savews             \ Call savews to put the character set in the correct
                        \ place

.char1

 RTS                    \ Return from the subroutine

ENDIF

                        \ --- End of added code ------------------------------->

[X]

Configuration variable OSBYTE = &FFF4

The address for the OSBYTE routine

[X]

Label char1 is local to this routine

[X]

Configuration variable savews = &DD06

The address for the savews workspace routine from the loader so we can call it to ensure the MOS characterdefinitions are loaded before printing text on the BBC Master

Utility routines: SwitchToCharSet

[Elite-A, Encyclopedia]