#include <stdint.h>

#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <curses.h>
#include "cpu.h"

#define WCOLS 80
#define WLINES 25
#define SEC_PER_TRK 0x24
#define HEADCNT 2

extern uint8_t byteregtable[8];
extern union _bytewordregs_ regs;
extern uint16_t segregs[4];
extern INTHOOK INTHOOKS[0x100];
extern uint8_t zf;

static FILE *fp;
WINDOW *bw, *dw, *w;
int lastkey = ERR;

static void int10() {
uint8_t cmd = regs.byteregs[regah];
uint8_t al = regs.byteregs[regal];
uint16_t dx = regs.wordregs[regdx];
switch (cmd) {
case 0x02: // at-xy
wmove(w, dx>>8, dx&0xff);
break;
case 0x0e: // emit
if (al >= 0x20 || al == '\n') {
wechochar(w, al);
} else if (al == 0x08) {
int y, x; getyx(w, y, x);
wmove(w, y, x-1);
}
break;
}
}

static void int13() {
uint8_t cmd = regs.byteregs[regah];
uint8_t al = regs.byteregs[regal];
uint8_t cl = regs.byteregs[regcl];
uint8_t ch = regs.byteregs[regch];
uint8_t dh = regs.byteregs[regdh];
uint16_t bx = regs.wordregs[regbx];
switch (cmd) {
case 0x02: // read disk sector(s)
case 0x03: // write disk sector(s)
// CL = sector number (1-based), AL = sector count
// DH = head number, CH = track number
// ES:BX = dest addr
fseek(fp, (((ch*HEADCNT*SEC_PER_TRK)+(dh*SEC_PER_TRK))+cl-1)*512, SEEK_SET);
for (int i=0; i<(al*512); i++) {
if (cmd == 0x03) { // write
fputc(getmem8(segregs[reges], bx+i), fp);
} else { // read
putmem8(segregs[reges], bx+i, fgetc(fp));
}
}
break;

case 0x08: // poll sectors per track / per head
// we just report a lot of them
regs.wordregs[regcx] = SEC_PER_TRK;
regs.byteregs[regdh] = HEADCNT-1;
break;
}
}

static void int16() {
uint8_t cmd = regs.byteregs[regah];
switch (cmd) {
case 0x00: // get keystroke
while (lastkey == ERR) {
lastkey = wgetch(w);
}
regs.byteregs[regal] = lastkey;
lastkey = ERR;
break;
case 0x01: // check for keystroke
if (lastkey == ERR) {
lastkey = wgetch(w);
}
zf = lastkey == ERR;
regs.byteregs[regal] = lastkey;
break;
}
}

static void usage()
{
fprintf(stderr, "Usage: ./pcat /path/to/fd\n");
}

int main(int argc, char *argv[])
{
if (argc < 2) {
usage();
return 1;
}
INTHOOKS[0x10] = int10;
INTHOOKS[0x13] = int13;
INTHOOKS[0x16] = int16;
reset86(0x7c00);
// initialize memory
fp = fopen(argv[1], "r");
if (!fp) {
fprintf(stderr, "Can't open %s\n", argv[1]);
return 1;
}
// read MBR into RAM
for (int i=0; i<512; i++) {
int c = getc(fp);
if (c != EOF) {
write86(0x7c00+i, c);
}
}
uint16_t magic = readw86(0x7dfe);
if (magic != 0xaa55) {
fprintf(stderr, "Invalid MBR magic %x\n", magic);
return 1;
}
initscr(); cbreak(); noecho(); nl(); clear();
// border window
bw = newwin(WLINES+2, WCOLS+2, 0, 0);
// TODO: I can't get this to work properly...
nodelay(bw, TRUE);
wborder(bw, 0, 0, 0, 0, 0, 0, 0, 0);
wrefresh(bw);
// debug panel
dw = newwin(1, 30, LINES-1, COLS-30);
w = newwin(WLINES, WCOLS, 1, 1);
scrollok(w, 1);
while (exec86(100));
nocbreak(); echo(); delwin(w); delwin(bw); delwin(dw); endwin();
printf("\nDone!\n");
fclose(fp);
return 0;
}