0100 ;BUTTERFINGERSõ0110 ;BY KEVIN C. GEVATOSKYõ0120 ;(c)1989, ANTIC PUBLISHING INC.õ0130 ;õ0140 DOSINI = $0Cõ0150 VKEYBD = $0208  ;KB int. vector.õ0160 KBCODE = $D209  ;Current key.õ0170 CH1 =   $02F2   ;Prior key.õ0180 CH  =   $02FC   ;Last key.õ0190 SH_CLR = 118    ;Key codes.õ0200 CT_CLR = 182õ0210 CT_SH_CLR = 246õ0220 ;õ0230     *=  $0600õ0240 ;õ0250 ;This program provides two entryõ0260 ;points so that it can beõ0270 ;started from DOS or BASIC.õ0280 ;õ0290 STARTõ0300     JMP INIT    ;For DOS entry.õ0310     NOP         ;For BASIC entryõ0320     PLA         ;w/ X=USR(1540)õ0330 ;õ0340 ;Makes the program RESET-proofõ0350 ;õ0360 INITõ0370     LDA DOSINI  ;Get current DOSõ0380     STA NEW_INI+1 ;init addressõ0390     LDA DOSINI+1 ;and save inõ0400     STA NEW_INI+2 ;new vector.õ0410     LDA # <NEW_INI ;Put addr ofõ0420     STA DOSINI  ;new vector inõ0430     LDA # >NEW_INI ;old vector.õ0440     STA DOSINI+1õ0450     BNE SET_KBVEC ;(JUMP)õ0460 ;õ0470 NEW_INIõ0480     JSR $FFFF   ;New DOS init.õ0490 ;õ0500 ;Jump here on initialization orõ0510 ;RESET to setup a new keyboardõ0520 ;trap vector.õ0530 ;õ0540 SET_KBVECõ0550     SEI         ;Kill IRQ's.õ0560     LDA VKEYBD  ;Save system KBõ0570     STA SYSKBV  ;interrupt addrõ0580     LDA VKEYBD+1 ;replace w/theõ0590     STA SYSKBV+1 ;addr to ourõ0600     LDA # <KEY_TRAP ;key-trapõ0610     STA VKEYBD  ;routine.õ0620     LDA # >KEY_TRAPõ0630     STA VKEYBD+1õ0640     CLI         ;Restore IRQ's.õ0650     RTS õ0660 ;õ0670 ;Interrupt routine to replaceõ0680 ;SHFT+CLEAR and CTRL+CLEARõ0690 ;with SHFT+CTRL+CLEAR.õ0700 ;õ0710 KEY_TRAPõ0720     PHA õ0730     LDA KBCODE  ;Get current keyõ0740     CMP #SH_CLR ;Filter out theõ0750     BEQ GOT_YA  ;standard clearõ0760 ;õ0770     CMP #CT_CLR ;screen keys.õ0780     BEQ GOT_YAõ0790 ;õ0800     CMP #CT_SH_CLR ; Check forõ0810     BNE GO_KB_INT ;  our specialõ0820 ;                    keyõ0830 CLR_SCR ;       combinationõ0840     LDA #SH_CLRõ0850     STA CH      ;Put clr-screenõ0860     STA CH1     ;code for Editorõ0870 GOT_YAõ0880     PLA         ;Return from theõ0890     PLA         ;interrupt.õ0900     RTI õ0910 ;õ0920 GO_KB_INTõ0930     PLA         ;Pass all otherõ0940     JMP (SYSKBV) ;keys on to OSõ0950 ;õ0960 SYSKBVõ0970     .DS 2       ;keybd handler.õ0980     *=  $02E0   ;DOS RUN addressõ0990     .WORD STARTõ1000     .END õ