v34gen.c

Linmodem is soft modem source code for embedded system

/* 
 * V34 constant data generator
 * 
 * Copyright (c) 1999,2000 Fabrice Bellard.
 *
 * This code is released under the GNU General Public License version
 * 2. Please read the file COPYING to know the exact terms of the
 * license.
 */
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <assert.h>

#include "dsp.h"

#define V34_SAMPLE_RATE_NUM 10
#define V34_SAMPLE_RATE_DEN 3
#define V34_SAMPLE_RATE ((2400*V34_SAMPLE_RATE_NUM)/V34_SAMPLE_RATE_DEN)
#define V22_TX_FILTER_SIZE (20 * 40)

#define RC_FILTER_SIZE 40

void find_data_rot(int *data_ptr, int *rot_ptr, int x0, int y0)
{
    int xx,yy,data,rot,x,y;

    /* find the data & rotation */
    for(data=0;data<4;data++) {
        x = -3 + (data & 1) * 4;
        y = -3 + (data >> 1) * 4;
        for(rot=0;rot<4;rot++) {
            if (x == x0 && y == y0) {
                *data_ptr = data;
                *rot_ptr = rot;
                return;
            }
            /* rotate by 90 */
            xx = y;
            yy = -x;
            x = xx;
            y = yy;
        }
    }
}


/* 0 : rotation by 180, 1 = rotation by 90 */
int classify(int x[2][2])
{
    int x0, y0, x1, y1,d0,d1,r0,r1;

    x0 = 2 * x[0][0] - 3;
    y0 = 2 * x[0][1] - 3;
    x1 = 2 * x[1][0] - 3;
    y1 = 2 * x[1][1] - 3;
    
    find_data_rot(&d0,&r0,x0,y0);
    find_data_rot(&d1,&r1,x1,y1);
    if (((r0 - r1) & 1) == 0)
        return 0;
    else
        return 1;
}


void gen_table(int nb_trans)
{
    int Y[5],Yt[5], trans, ss[2][3], xx[2][2];
    int res, i, y0;

    printf("u8 trellis_trans_%d[256][4] = {\n",
           nb_trans);
    
    for(y0=0;y0<2;y0++) {

    for(trans=0;trans<nb_trans;trans++) {
        printf(" /* trans=%d y0=%d */\n", trans, y0);
        Yt[1] = trans & 1;
        Yt[2] = (trans >> 1) & 1;
        Yt[4] = (trans >> 2) & 1;
        Yt[3] = (trans >> 3) & 1;

    for(xx[0][0] = 0; xx[0][0] < 4; xx[0][0]++)
    for(xx[0][1] = 0; xx[0][1] < 4; xx[0][1]++)
    for(xx[1][0] = 0; xx[1][0] < 4; xx[1][0]++)
    for(xx[1][1] = 0; xx[1][1] < 4; xx[1][1]++) {
        
        /* (