xv6/kbd.c

52 lines
1.1 KiB
C

#include "types.h"
#include "x86.h"
#include "defs.h"
#include "kbd.h"
int kbdgetc(void) {
static uint shift;
static uchar *charcode[4] = {
normalmap, shiftmap, ctlmap, ctlmap
};
uint st, data, c;
st = inb(KBSTATP);
if ((st & KBS_DIB) == 0) {
return -1;
}
data = inb(KBDATAP);
if (data == 0xE0) {
shift |= E0ESC;
return 0;
}
else if (data & 0x80) {
// Key released
data = (shift & E0ESC ? data : data & 0x7F);
shift &= ~(shiftcode[data] | E0ESC);
return 0;
}
else if (shift & E0ESC) {
// Last character was an E0 escape; or with 0x80
data |= 0x80;
shift &= ~E0ESC;
}
shift |= shiftcode[data];
shift ^= togglecode[data];
c = charcode[shift & (CTL | SHIFT)][data];
if (shift & CAPSLOCK) {
if ('a' <= c && c <= 'z') {
c += 'A' - 'a';
}
else if ('A' <= c && c <= 'Z') {
c += 'a' - 'A';
}
}
return c;
}
void kbdintr(void) {
consoleintr(kbdgetc);
}