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/*============================================================================
* Syntax: [sys, x0, str, ts] = simrsdbv(t, x, u, flag, n, k, tp, dim);
*SIMBCHDC SIMULINK S-function for Reed-Solomon decode.
* The m-file is designed to be used in a SIMULINK S-Function block.
* This function will decode the cyclic code using RS decode method.
* Parameters: n -- length of code word.
* k -- length of message.
* t -- error-correction capability.
* tp-- list of all GF(2^M) elements. n=2^M-1.
*
* The output has length n+1, the last digit is the error signal err.
* A non-negative err indicates number of errors have been corrected.
* A nagative err indicates that more than t error have been found in
* in the code, the routine cannot correct such error.
*============================================================================
* Original designed by Wes Wang,
* Jun Wu, The Mathworks, Inc.
* Feb-07, 1996
*
* Copyright (c) 1996 by The MAthWorks, Inc.
* All Rights Reserved
* $Revision: 1.1 $ $Date: 1996/04/01 19:05:06 $
*============================================================================
*/
#define S_FUNCTION_NAME simrsdbv
/* need to include simstruc.h for the definition of the SimStruct and
* its associated macro definitions.
*/
#include "simstruc.h"
#include "gflib.c"
#ifdef MATLAB_MEX_FILE
#include "mex.h" /* needed for declaration of mexErrMsgTxt */
#endif
#define NUM_ARGS 4 /* four additional input arguments */
#define N ssGetArg(S,0)
#define K ssGetArg(S,1)
#define P ssGetArg(S,2)
#define DIM ssGetArg(S,3)
#define Prim 2
/*elseif flag == 0
* if 2^dim-1 ~= n
* error('Reed-Solomon decode has illegal code word length')
* end;
* sys(1) = 0; % no continuous state
* sys(2) = 0;
* sys(3) = k * dim + 1; % number of output, code word length plus one.
* sys(4) = n * dim + 1; % number of input, message length.
* sys(5) = 0;
* sys(6) = 1; % direct through flag.
* sys(7) = 1; % one sample rate
* x0 = [];
* ts = [-1, 0];
*else
* sys = [];
*end;
*/
static void mdlInitializeSizes(S)
SimStruct *S;
{
int i, np;
int n = (int)mxGetPr(N)[0];
int k = (int)mxGetPr(K)[0];
int dim = (int)mxGetPr(DIM)[0];
np = 1;
for(i=0; i < dim; i++)
np = np*2;
if ( np-1 != n ){
#ifdef MATLAB_MEX_FILE
mexErrMsgTxt("Reed-Solomon decode has illegal code word length");
#endif
}
ssSetNumContStates( S, 0); /* no continuous states */
ssSetNumDiscStates( S, 0); /* no discrete states */
ssSetNumOutputs( S, k*dim+1); /* number of output, code word length plus one*/
ssSetNumInputs( S, n*dim+1); /* number of inputs, message length*/
ssSetDirectFeedThrough( S, 1); /* direct feedthrough flag */
ssSetNumSampleTimes( S, 1); /* number of sample times */
ssSetNumInputArgs( S, NUM_ARGS); /* number of input arguments*/
ssSetNumRWork( S, 0);
ssSetNumIWork( S, (n-2*k+7*dim+20)*n+4*dim+k*(k-12)+28);
/* n --------------- code_word
* (n+1)*dim ------- pp
* n*dim ----------- tmpRoom
* k --------------- msg
* n --------------- ccode
* 1 --------------- err
* (n-2*k+5*dim+18)*n
* +3*dim+k*(k-13)+27 --- Iwork for rscore()
*/
ssSetNumPWork( S, 0);
}
/*
* mdlInitializeConditions - initialize the states
* Initialize the states, Integers and real-numbers
*/
static void mdlInitializeConditions(x0, S)
double *x0;
SimStruct *S;
{
int i;
int n = (int)mxGetPr(N)[0];
int k = (int)mxGetPr(K)[0];
int dim = (int)mxGetPr(DIM)[0];
int *code_word, *pp, *tmpRoom, *msg, *ccode, *err, *IworkRscore;
double *p= mxGetPr(P);
code_word = ssGetIWork(S);
pp = ssGetIWork(S) + n;
tmpRoom = ssGetIWork(S) + n + (n+1)*dim;
msg = ssGetIWork(S) + n + (n+1)*dim + n*dim;
ccode = ssGetIWork(S) + n + (n+1)*dim + n*dim + k;
err = ssGetIWork(S) + n + (n+1)*dim + n*dim + k + n;
IworkRscore = ssGetIWork(S) + n + (n+1)*dim + n*dim + k + n + 1;
for( i=0; i<(n+1)*dim; i++ )
pp[i] = (int)p[i];
}
/*
* mdlInitializeSampleTimes - initialize the sample times array
*
* This function is used to specify the sample time(s) for your S-function.
* If your S-function is continuous, you must specify a sample time of 0.0.
* Sample times must be registered in ascending order.
*/
static void mdlInitializeSampleTimes(S)
SimStruct *S;
{
ssSetSampleTimeEvent(S, 0, 0.0);
ssSetOffsetTimeEvent(S, 0, 0.0);
}
/*if (flag == 3)
* % refresh the state only when there is a trigger signal
* len_u = length(u);
* if u(len_u)
* % main calculation
* code_word = bi2de(vec2mat(u(1:len_u-1), dim)) - 1;
* [sys, err] = rscore(code_word, k, tp, dim, n);
* % output is the combination of message and error information.
* sys = sys +1;
* indx = find(~(sys >= 0));
* sys(indx) = indx - indx;
* sys = de2bi(sys, dim)';
* sys = sys(:);
* sys = [sys(:); err];
* else
* % if there is no trigger, no calculation.
* if t <= 0
* sys = zeros(k*dim+1, 1);
* end;
* end;
*/
/* mdlOutputs - compute the outputs
* In this function, you compute the outputs of your S-function
* block. The outputs are placed in the y variable.
*/
static void mdlOutputs(y, x, u, S, tid)
double *y, *x, *u;
SimStruct *S;
int tid;
{
int i, j, tmp;
int n = (int)mxGetPr(N)[0];
int k = (int)mxGetPr(K)[0];
int dim = (int)mxGetPr(DIM)[0];
int *code_word, *pp, *tmpRoom, *msg, *ccode, *err, *IworkRscore;
double *p= mxGetPr(P);
double t;
t = ssGetT(S);
code_word = ssGetIWork(S);
pp = ssGetIWork(S) + n;
tmpRoom = ssGetIWork(S) + n + (n+1)*dim;
msg = ssGetIWork(S) + n + (n+1)*dim + n*dim;
ccode = ssGetIWork(S) + n + (n+1)*dim + n*dim + k;
err = ssGetIWork(S) + n + (n+1)*dim + n*dim + k + n;
IworkRscore = ssGetIWork(S) + n + (n+1)*dim + n*dim + k + n + 1;
if( u[n*dim] != 0 ){
for( i=0; i<(n+1)*dim; i++ )
pp[i] = (int)p[i];
for(i=0; i < dim; i++){
for(j=0; j < n; j++)
tmpRoom[i*n+j] = (int)u[i+j*dim];
}
bi2de(tmpRoom, n, dim, Prim, code_word);
for(i=0; i < n; i++)
code_word[i] = code_word[i] - 1;
rscore(code_word,k,pp,dim,n,IworkRscore,err,ccode);
for(i=n-k; i < n; i++)
msg[i-n+k] = ccode[i];
for(i=0; i < k; i++){
if( msg[i]+1 < 0 )
msg[i] = 0;
else
msg[i] = msg[i] + 1;
}
for(i=0; i < k; i++){
tmp = msg[i];
for(j=0; j < dim; j++){
y[i*dim+j] = (double)(tmp % Prim);
if(j < dim-1)
tmp = (int)tmp/Prim;
}
}
y[k*dim] = (double)err[0];
}else{
if ( t <= 0 ){
for(i=0; i < k*dim+1; i++)
y[i] = 0;
}
}
}
/*
* mdlUpdate - perform action at major integration time step
*
* This function is called once for every major integration time step.
* Discrete states are typically updated here, but this function is useful
* for performing any tasks that should only take place once per integration
* step.
*/
static void mdlUpdate(x, u, S, tid)
double *x, *u;
SimStruct *S;
int tid;
{
}
/*
* mdlDerivatives - compute the derivatives
*
* In this function, you compute the S-function block's derivatives.
* The derivatives are placed in the dx variable.
*/
static void mdlDerivatives(dx, x, u, S, tid)
double *dx, *x, *u;
SimStruct *S;
int tid;
{
}
/*
* mdlTerminate - called when the simulation is terminated.
*
* In this function, you should perform any actions that are necessary
* at the termination of a simulation. For example, if memory was allocated
* in mdlInitializeConditions, this is the place to free it.
*/
static void mdlTerminate(S)
SimStruct *S;
{
}
#ifdef MATLAB_MEX_FILE /* Is this file being compiled as a MEX-file? */
#include "simulink.c" /* MEX-file interface mechanism */
#else
#include "cg_sfun.h" /* Code generation registration function */
#endif