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annotate src/dos/keyb.c @ 8:c0e8bbf96849

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author John Tsiombikas <nuclear@member.fsf.org>
date Mon, 19 Jan 2015 15:49:36 +0200
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nuclear@7 1 /*
nuclear@7 2 DOS interrupt-based keyboard driver.
nuclear@7 3 Copyright (C) 2013 John Tsiombikas <nuclear@member.fsf.org>
nuclear@7 4
nuclear@7 5 This program is free software: you can redistribute it and/or modify
nuclear@7 6 it under the terms of the GNU General Public License as published by
nuclear@7 7 the Free Software Foundation, either version 3 of the License, or
nuclear@7 8 (at your option) any later version.
nuclear@7 9
nuclear@7 10 This program is distributed in the hope that it will be useful,
nuclear@7 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@7 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@7 13 GNU General Public License for more details.
nuclear@7 14
nuclear@7 15 You should have received a copy of the GNU General Public License
nuclear@7 16 along with the program. If not, see <http://www.gnu.org/licenses/>
nuclear@7 17 */
nuclear@7 18 #define KEYB_C_
nuclear@7 19
nuclear@7 20 #include <stdio.h>
nuclear@7 21 #include <stdlib.h>
nuclear@7 22 #include <string.h>
nuclear@7 23 #include <conio.h>
nuclear@7 24 #include <dos.h>
nuclear@7 25 #include <i86.h>
nuclear@7 26 #include "keyb.h"
nuclear@7 27 #include "scancode.h"
nuclear@7 28
nuclear@7 29 #define KB_INTR 0x9
nuclear@7 30 #define KB_PORT 0x60
nuclear@7 31
nuclear@7 32 #define PIC1_CMD_PORT 0x20
nuclear@7 33 #define OCW2_EOI (1 << 5)
nuclear@7 34
nuclear@7 35 #define DONE_INIT (prev_handler)
nuclear@7 36
nuclear@7 37 static void __interrupt __far kbintr();
nuclear@7 38
nuclear@7 39 static void (__interrupt __far *prev_handler)();
nuclear@7 40
nuclear@7 41 static int *buffer;
nuclear@7 42 static int buffer_size, buf_ridx, buf_widx;
nuclear@7 43 static int last_key;
nuclear@7 44
nuclear@7 45 static unsigned int num_pressed;
nuclear@7 46 static unsigned char keystate[256];
nuclear@7 47
nuclear@7 48 #define ADVANCE(x) ((x) = ((x) + 1) % buffer_size)
nuclear@7 49
nuclear@7 50 int kb_init(int bufsz)
nuclear@7 51 {
nuclear@7 52 if(DONE_INIT) {
nuclear@7 53 fprintf(stderr, "keyboard driver already initialized!\n");
nuclear@7 54 return 0;
nuclear@7 55 }
nuclear@7 56
nuclear@7 57 buffer_size = bufsz;
nuclear@7 58 if(buffer_size && !(buffer = malloc(buffer_size * sizeof *buffer))) {
nuclear@7 59 fprintf(stderr, "failed to allocate input buffer, continuing without\n");
nuclear@7 60 buffer_size = 0;
nuclear@7 61 }
nuclear@7 62 buf_ridx = buf_widx = 0;
nuclear@7 63 last_key = -1;
nuclear@7 64
nuclear@7 65 memset(keystate, 0, sizeof keystate);
nuclear@7 66 num_pressed = 0;
nuclear@7 67
nuclear@7 68 /* set our interrupt handler */
nuclear@7 69 _disable();
nuclear@7 70 prev_handler = _dos_getvect(KB_INTR);
nuclear@7 71 _dos_setvect(KB_INTR, kbintr);
nuclear@7 72 _enable();
nuclear@7 73
nuclear@7 74 return 0;
nuclear@7 75 }
nuclear@7 76
nuclear@7 77 void kb_shutdown(void)
nuclear@7 78 {
nuclear@7 79 if(!DONE_INIT) {
nuclear@7 80 return;
nuclear@7 81 }
nuclear@7 82
nuclear@7 83 /* restore the original interrupt handler */
nuclear@7 84 _disable();
nuclear@7 85 _dos_setvect(KB_INTR, prev_handler);
nuclear@7 86 _enable();
nuclear@7 87
nuclear@7 88 free(buffer);
nuclear@7 89 }
nuclear@7 90
nuclear@7 91 int kb_isdown(int key)
nuclear@7 92 {
nuclear@7 93 switch(key) {
nuclear@7 94 case KB_ANY:
nuclear@7 95 return num_pressed;
nuclear@7 96
nuclear@7 97 case KB_ALT:
nuclear@7 98 return keystate[KB_LALT] + keystate[KB_RALT];
nuclear@7 99
nuclear@7 100 case KB_CTRL:
nuclear@7 101 return keystate[KB_LCTRL] + keystate[KB_RCTRL];
nuclear@7 102 }
nuclear@7 103 return keystate[key];
nuclear@7 104 }
nuclear@7 105
nuclear@7 106 void kb_wait(void)
nuclear@7 107 {
nuclear@7 108 int key;
nuclear@7 109 while((key = kb_getkey()) == -1) {
nuclear@7 110 /* put the processor to sleep while waiting for keypresses, but first
nuclear@7 111 * make sure interrupts are enabled, or we'll sleep forever
nuclear@7 112 */
nuclear@7 113 __asm {
nuclear@7 114 sti
nuclear@7 115 hlt
nuclear@7 116 }
nuclear@7 117 }
nuclear@7 118 kb_putback(key);
nuclear@7 119 }
nuclear@7 120
nuclear@7 121 int kb_getkey(void)
nuclear@7 122 {
nuclear@7 123 int res;
nuclear@7 124
nuclear@7 125 if(buffer) {
nuclear@7 126 if(buf_ridx == buf_widx) {
nuclear@7 127 return -1;
nuclear@7 128 }
nuclear@7 129 res = buffer[buf_ridx];
nuclear@7 130 ADVANCE(buf_ridx);
nuclear@7 131 } else {
nuclear@7 132 res = last_key;
nuclear@7 133 last_key = -1;
nuclear@7 134 }
nuclear@7 135 return res;
nuclear@7 136 }
nuclear@7 137
nuclear@7 138 void kb_putback(int key)
nuclear@7 139 {
nuclear@7 140 if(buffer) {
nuclear@7 141 /* go back a place */
nuclear@7 142 if(--buf_ridx < 0) {
nuclear@7 143 buf_ridx += buffer_size;
nuclear@7 144 }
nuclear@7 145
nuclear@7 146 /* if the write end hasn't caught up with us, go back one place
nuclear@7 147 * and put it there, otherwise just overwrite the oldest key which
nuclear@7 148 * is right where we were.
nuclear@7 149 */
nuclear@7 150 if(buf_ridx == buf_widx) {
nuclear@7 151 ADVANCE(buf_ridx);
nuclear@7 152 }
nuclear@7 153
nuclear@7 154 buffer[buf_ridx] = key;
nuclear@7 155 } else {
nuclear@7 156 last_key = key;
nuclear@7 157 }
nuclear@7 158 }
nuclear@7 159
nuclear@7 160 static void __interrupt __far kbintr()
nuclear@7 161 {
nuclear@7 162 unsigned char code;
nuclear@7 163 int key, press;
nuclear@7 164
nuclear@7 165 code = inp(KB_PORT);
nuclear@7 166
nuclear@7 167 if(code >= 128) {
nuclear@7 168 press = 0;
nuclear@7 169 code -= 128;
nuclear@7 170
nuclear@7 171 if(num_pressed > 0) {
nuclear@7 172 num_pressed--;
nuclear@7 173 }
nuclear@7 174 } else {
nuclear@7 175 press = 1;
nuclear@7 176
nuclear@7 177 num_pressed++;
nuclear@7 178 }
nuclear@7 179
nuclear@7 180 key = scantbl[code];
nuclear@7 181
nuclear@7 182 if(press) {
nuclear@7 183 /* append to buffer */
nuclear@7 184 last_key = key;
nuclear@7 185 if(buffer_size > 0) {
nuclear@7 186 buffer[buf_widx] = key;
nuclear@7 187 ADVANCE(buf_widx);
nuclear@7 188 /* if the write end overtook the read end, advance the read end
nuclear@7 189 * too, to discard the oldest keypress from the buffer
nuclear@7 190 */
nuclear@7 191 if(buf_widx == buf_ridx) {
nuclear@7 192 ADVANCE(buf_ridx);
nuclear@7 193 }
nuclear@7 194 }
nuclear@7 195 }
nuclear@7 196
nuclear@7 197 /* and update keystate table */
nuclear@7 198 keystate[key] = press;
nuclear@7 199
nuclear@7 200 outp(PIC1_CMD_PORT, OCW2_EOI); /* send end-of-interrupt */
nuclear@7 201 }