mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-20 22:18:06 +11:00
147 lines
4.2 KiB
NASM
147 lines
4.2 KiB
NASM
; kbd - implement GetC for PS/2 keyboard
|
|
;
|
|
; It reads raw key codes from a FetchKC routine and returns, if appropriate,
|
|
; a proper ASCII char to type. See recipes rc2014/ps2 and sms/kbd.
|
|
;
|
|
; *** Defines ***
|
|
; Pointer to a routine that fetches the last typed keyword in A. Should return
|
|
; 0 when nothing was typed.
|
|
; KBD_FETCHKC
|
|
|
|
; *** Consts ***
|
|
.equ KBD_KC_BREAK 0xf0
|
|
.equ KBD_KC_EXT 0xe0
|
|
.equ KBD_KC_LSHIFT 0x12
|
|
.equ KBD_KC_RSHIFT 0x59
|
|
|
|
; *** Variables ***
|
|
; Set to previously received scan code
|
|
.equ KBD_PREV_KC KBD_RAMSTART
|
|
; Whether Shift key is pressed
|
|
.equ KBD_SHIFT_ON KBD_PREV_KC+1
|
|
.equ KBD_RAMEND KBD_SHIFT_ON+1
|
|
|
|
kbdInit:
|
|
xor a
|
|
ld (KBD_PREV_KC), a
|
|
ld (KBD_SHIFT_ON), a
|
|
ret
|
|
|
|
kbdGetC:
|
|
call KBD_FETCHKC
|
|
or a
|
|
jr z, .nothing
|
|
|
|
; scan code not zero, maybe we have something.
|
|
; Do we need to skip it?
|
|
ex af, af' ; save fetched KC
|
|
ld a, (KBD_PREV_KC)
|
|
; Whatever the KC, the new A becomes our prev. The easiest way to do
|
|
; this is to do it now.
|
|
ex af, af' ; restore KC
|
|
ld (KBD_PREV_KC), a
|
|
ex af, af' ; restore prev KC
|
|
; If F0 (break code) or E0 (extended code), we skip this code
|
|
cp KBD_KC_BREAK
|
|
jr z, .break
|
|
cp KBD_KC_EXT
|
|
jr z, .ignore
|
|
ex af, af' ; restore saved KC
|
|
cp 0x80
|
|
jr nc, .ignore
|
|
; No need to skip, code within bounds, we have something!
|
|
call .isShift
|
|
jr z, .shiftPressed
|
|
; Let's see if there's a ASCII code associated to it.
|
|
push hl ; --> lvl 1
|
|
ld hl, KBD_SHIFT_ON
|
|
bit 0, (hl)
|
|
ld hl, kbdScanCodes ; no flag changed
|
|
jr z, .shiftNotPressed
|
|
; Shift is being pressed. Use Shifted table.
|
|
ld hl, kbdScanCodesS
|
|
.shiftNotPressed:
|
|
call addHL
|
|
ld a, (hl)
|
|
pop hl ; <-- lvl 1
|
|
or a
|
|
jp z, unsetZ ; no code. Keep A at 0, but unset Z
|
|
; We have something!
|
|
cp a ; ensure Z
|
|
ret
|
|
.shiftPressed:
|
|
ld a, 1
|
|
ld (KBD_SHIFT_ON), a
|
|
jr .ignore ; to actual char to return
|
|
.break:
|
|
ex af, af' ; restore saved KC
|
|
call .isShift
|
|
jr nz, .ignore
|
|
; We had a shift break, update status
|
|
xor a
|
|
ld (KBD_SHIFT_ON), a
|
|
; continue to .ignore
|
|
.ignore:
|
|
; A scan code over 0x80 is out of bounds or prev KC tell us we should
|
|
; skip. Ignore.
|
|
xor a
|
|
jp unsetZ
|
|
.nothing:
|
|
; We have nothing. Before we go further, we'll wait a bit to give our
|
|
; device the time to "breathe". When we're in a "nothing" loop, the z80
|
|
; hammers the device really fast and continuously generates interrupts
|
|
; on it and it interferes with its other task of reading the keyboard.
|
|
push bc
|
|
ld b, 0
|
|
.wait:
|
|
nop
|
|
djnz .wait
|
|
pop bc
|
|
jp unsetZ
|
|
; Whether KC in A is L or R shift
|
|
.isShift:
|
|
cp KBD_KC_LSHIFT
|
|
ret z
|
|
cp KBD_KC_RSHIFT
|
|
ret
|
|
|
|
; A list of the values associated with the 0x80 possible scan codes of the set
|
|
; 2 of the PS/2 keyboard specs. 0 means no value. That value is a character than
|
|
; can be read in a GetC routine. No make code in the PS/2 set 2 reaches 0x80.
|
|
kbdScanCodes:
|
|
; 0x00 1 2 3 4 5 6 7 8 9 a b c d e f
|
|
.db 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9,'`', 0
|
|
; 0x10 9 = TAB
|
|
.db 0, 0, 0, 0, 0,'q','1', 0, 0, 0,'z','s','a','w','2', 0
|
|
; 0x20 32 = SPACE
|
|
.db 0,'c','x','d','e','4','3', 0, 0, 32,'v','f','t','r','5', 0
|
|
; 0x30
|
|
.db 0,'n','b','h','g','y','6', 0, 0, 0,'m','j','u','7','8', 0
|
|
; 0x40 59 = ;
|
|
.db 0,',','k','i','o','0','9', 0, 0,'.','/','l', 59,'p','-', 0
|
|
; 0x50 13 = RETURN 39 = '
|
|
.db 0, 0, 39, 0,'[','=', 0, 0, 0, 0, 13,']', 0,'\', 0, 0
|
|
; 0x60 8 = BKSP
|
|
.db 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0
|
|
; 0x70 27 = ESC
|
|
.db 0, 0, 0, 0, 0, 0, 27, 0, 0, 0, 0, 0, 0, 0, 0, 0
|
|
|
|
; Same values, but shifted
|
|
kbdScanCodesS:
|
|
; 0x00 1 2 3 4 5 6 7 8 9 a b c d e f
|
|
.db 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9,'~', 0
|
|
; 0x10 9 = TAB
|
|
.db 0, 0, 0, 0, 0,'Q','!', 0, 0, 0,'Z','S','A','W','@', 0
|
|
; 0x20 32 = SPACE
|
|
.db 0,'C','X','D','E','$','#', 0, 0, 32,'V','F','T','R','%', 0
|
|
; 0x30
|
|
.db 0,'N','B','H','G','Y','^', 0, 0, 0,'M','J','U','&','*', 0
|
|
; 0x40 59 = ;
|
|
.db 0,'<','K','I','O',')','(', 0, 0,'>','?','L',':','P','_', 0
|
|
; 0x50 13 = RETURN 39 = '
|
|
.db 0, 0, 39, 0,'{','+', 0, 0, 0, 0, 13,'}', 0,'|', 0, 0
|
|
; 0x60 8 = BKSP
|
|
.db 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0
|
|
; 0x70 27 = ESC
|
|
.db 0, 0, 0, 0, 0, 0, 27, 0, 0, 0, 0, 0, 0, 0, 0, 0
|