Key redefinition library
This is a little library to allow you to scan keyboard, test keys and redefine them.Functions are explained in source code.
Keycodes returned by GetPressed and used for IsPressed/GetMask are the same than firmware keycodes (you know the one you have on disc plate on CPC 664/6128)
For performance , it is possible to compute directly offset and mask in keyboard buffer with GetMask function.This is usefull for game as IsPressed function can be considered as slow.
As SHIFT or CONTROL status can be a problem , you can inhibate them using IgnoreSHITFCTRL.
;simple keyboard module ;no extra functions , just scan and locate a key ;no char buffer , no antibounce, ect... ;SJASM syntax MODULE key ;do a complete key scan and store it at (HL) ;altered : AF - BC - DE Scan push HL ld BC,#F782 out (C),C ld BC,#F40e ld E,B out (C),C ld BC,#F6c0 ld D,B out (C),C ld C,0 out (C),C ld BC,#F792 out (C),C ld A,#40 ld C,#4A .loop ld B,D out (C),A ld B,E ini inc A cp C jr c,.loop ld BC,#F782 out (C),C pop HL ret ;check if there is a key is down at (HL) ;only the first key found is returned ;return carry is a key is down ;return key code in A : key code = (line*8)+bit ;returned code is the same than system ;altered : AF - BC GetPressed push HL ld C,10 .loop_col ld B,8 ld A,(HL++) .loop_bit rla jr nc,.pressed djnz .loop_bit dec C jr nz,.loop_col or A ;no key found ! pop HL ret .pressed dec C ld A,9 sub C add A ;*2 add A ;*4 add A ;*8 dec B or B ;add bit scf ;key found ! pop HL ret ;check if a key is pressed ;A = key code ;HL = 10 byte array scanned with Scan function ;return key state in carry ;altered AF - DE - B IsPressed push HL push AF ; keep bit and %01111000 rrca rrca rrca ld E,A ld D,0 add HL,DE ;so we get the address pop AF and 7 inc A ld B,A ld A,(HL) ;get line .loop rra ;get bit in carry djnz .loop ccf ;reverse bit pop HL ret ;compute offset and mask for a key ;A = key code ;return offset in C and mask in B ;altered AF - BC GetMask ld B,A ;get offset and %01111000 rrca rrca rrca ld C,A ;get mask ld A,B and %00000111 ld B,A ld A,1 jr z,.done .loop add A djnz .loop .done ld B,A ret ;erase SHIFT and CONTROL status ;used when that can be a problem , like with IsPressed ;HL = 10 byte array scanned with Scan function ;altered : AF IgnoreSHITFCTRL push HL inc HL inc HL ld A,(HL) or %10100000 ld (HL),A pop HL ret ENDMODULE