/* rtty med HAMCOMM-interfacet */

/* rtty med HAMCOMM-interfacet */

#include <stdio.h>
#include <conio.h>
#include <dos.h>
#include <bios.h>
#include <mem.h>
#include <math.h>

extern void cmpt_init(void);
extern void cmpt_exit(void);
extern unsigned tone_freq;
unsigned old_tonefreq;
extern unsigned int timerticks;
unsigned char letter;
unsigned char c;
int smp_cntr;

#define LTRS 0x1f
#define FGRS 0x1b
#define LTRS_OFF 0
#define FGRS_OFF 32
int tab_offs = LTRS_OFF;

unsigned char b2a_tab[] =
{

0, 'T', 13, 'O', ' ', 'H', 'N', 'M', 10, 'L', 'R', 'G', 'I', 'P', 'C',
'V', 'E', 'Z', 'D', 'B', 'S', 'Y', 'F', 'X', 'A', 'W', 'J', '*', 'U', 'Q',
'K', '*',

0, '5', 13, '9', ' ', 0, ',', '.', 10, ')', '4', 0, '8', '0', ':',
'=', '3', '+', 0, '?', 0, '6', 0, '/', '-', '2', 7, '*', '7', '1',
'(', '*'

};

char scrbuf[4000];

unsigned fc,markfreq,spacefreq,shift;
float baud;
unsigned wait_tm;
int x_sav,y_sav;
unsigned freq_cntr,noise_cntr;

int rev;
char *nrmrevstr[2] = {"NORMAL","REVERSE"};
unsigned maxval;

main()
{
int i;

cmpt_init();
clrscr();

fc=2200;
baud=45.45;
shift=170;
rev=0;
set_freqs(1);

tone_freq=0;

while(1) {
maxval=(shift/2)-5;
freq_cntr = 0;

while(1) {
if((tone_freq >= spacefreq-maxval) && (tone_freq <= spacefreq+maxval))
freq_cntr++;
else
freq_cntr=0;

if(freq_cntr==30) break;

if(kbhit())
if(process_key())
break;
else
goto rdy;
}

wait_tm=(unsigned)(1193180l/baud);
wait(wait_tm+(wait_tm/2));
do_letter();

if(kbhit())
if(! process_key()) break;
}
rdy:
cmpt_exit();
}

process_key()
{
int c;

c = getch();
if(c==0) {
c=getch();
switch(c){
case 0x30: set_baud(); /* Alt-B */
break;
case 0x1f: set_shift(); /* Alt-S */
break;
case 0x2e: set_fc(); /* Alt-C */
break;
case 0x13: rev ^= 1; /* Alt-R */
set_freqs(1);
break;
case 0x14: tune(); /* Alt-T */
break;
case 0x2d: return 0; /* Alt-X */
}
}
return 1;
}

set_baud()
{
char baudstr[20];

printf("\nEnter baud rate: ");
gets(baudstr);
baud = atof(baudstr);
}

set_shift()
{
char shiftstr[20];

printf("\nEnter shift: ");
gets(shiftstr);
shift = atoi(shiftstr);
set_freqs(0);
}

set_fc()
{
char fcstr[20];

printf("\nEnter Center frequency: ");
gets(fcstr);
fc = atoi(fcstr);
set_freqs(0);
}

tune()
{
int center_x,tone_x;

HideCur();
cursave();
save_scr();
clrscr();

center_x=fc/50;

gotoxy(1+center_x,1);
putch('*');

while(1) {
if(tone_x != center_x) {
gotoxy(1+tone_x,1);
putch(' ');
}
tone_x=tone_freq/50;
gotoxy(1+tone_x,1);
putch('|');
if(tone_x == center_x){
gotoxy(1+center_x,1);
putch('*');
}

if(kbhit()){
getch();
break;
}
}
rest_scr();
currest();
ShowCur(6,7);
}

do_letter()
{
int i,err;
unsigned t;

letter = 0x00;
err=0;

for(i=0;i<5;i++){
letter <<= 1;
if((tone_freq >= markfreq-maxval) && (tone_freq <= markfreq+maxval))
letter |= 0x01;
else if((tone_freq >= spacefreq-maxval) && (tone_freq <= spacefreq+maxval))
letter |= 0x00;
else err=1;
wait(wait_tm);
}

if(! err){
switch(letter) {
case LTRS: tab_offs = LTRS_OFF;
break;
case FGRS: tab_offs = FGRS_OFF;
break;
default: c = b2a_tab[tab_offs+letter];
putchar(c);
}
}
}

set_freqs(int with_text)
{
switch(rev){
case 0: markfreq = fc+shift/2;
spacefreq = fc-shift/2;
break;
case 1: markfreq = fc-shift/2;
spacefreq = fc+shift/2;
}
if(with_text)
printf("\nNrm/Rev: %s\n",nrmrevstr[rev]);
}

wait(unsigned t)
{
unsigned latch1,latch2;

asm{
push ax
push dx
mov al,00h
out 43h,al
in al,40h
mov dl,al
in al,40h
mov dh,al
mov latch1,dx
pop dx
pop ax
}

while(1) {
asm{
push ax
push dx
mov al,00h
out 43h,al /* latch current counter value */
in al,40h
mov dl,al
in al,40h
mov dh,al
mov latch2,dx
pop dx
pop ax
}
if(latch1-latch2 >= t)
break;
}
}

HideCur()
{
asm{
push ax
push cx

mov ah,01h
mov ch,00100110b
mov cl,00000111b
int 10H

pop cx
pop ax
}
}

ShowCur(char start, char end)
{
asm{
push ax
push cx

mov ah,01H
mov ch,start
mov cl,end
int 10H

pop cx
pop ax
}
}

cursave()
{
x_sav = wherex();
y_sav = wherey();
}

currest()
{
gotoxy(x_sav,y_sav);
}

save_scr() {
char far* p;
p = MK_FP(0xb800,0x0000);
_fmemcpy((char far*)scrbuf,p,4000);
}
rest_scr()
{
char far* p;

p = MK_FP(0xb800,0x0000);
_fmemcpy(p,(char far*)scrbuf,4000);
}