Miscalleneous routines III

THE 'COPY SCREEN' ROUTINE
This routine has two entry points. The first one, #301D, is used with the BASIC commands
'SAVE/LOAD/VERIFY/MERGE SCREEN$'. The second entry point (#3020) is used for the 'COPY'
command itself. Depending on the parameter following the 'SCREEN$', the normal or the
grey scale screen dump is used.

301D DUMP_SCR$  POP  HL                  Drop the return address (within the
                                         routine which called 'EXPT_PARMS').
301E            JR   #3026,COPY_1        Jump forward.

3020 COPY       RST  #28,NEXT_C          Advance CH_ADD.
3021            CP   170,"SCREEN$"       Give 'Nonsense in G+DOS' error if
3023            JP   NZ,#1644,REP_0      command isn't followed by 'SCREEN$'.
3026 COPY_1     LD   A,49,"1"            Default is '1' for 'normal' dump.
3028            LD   (#3E00),A
302B            RST  #28,NEXT_C          Advance CH_ADD
302C            CP   13
302E            JR   Z,#3038,COPY_2      Jump with ENTER.
3030            CP   58,":"
3032            JR   Z,#3038,COPY_2      Also jump with ':'.
3034            LD   (#3E00),A           Otherwise store character.
3037            RST  #28,NEXT_C          Update CH_ADD again.
3038 COPY_2     CALL #3148,ST_END_RAM    Confirm end of statement and exit
                                         during syntax checking.
303B            LD   A,(#3E00)
303E            CP   49,"1"              Normal screendump if '1' followed the
3040            CALL Z,#12D2,COPS        'SCREEN$'.
3043            CP   50,"2"              Grey scale in case of a '2'.
3045            CALL Z,#133E,COPS2       Ignore other values.
3048            JP   #047C,END           Finished.