//---------------------------------------------------------------------------
#include  <stdio.h>
#include  <stdlib.h>
#include  <string.h>
#pragma hdrstop
/*
 (c)数理設計研究所　玉置
    Mathematical Assist Design Hal.T 2002/11/23
    線型Ｍ系列タップ計算機

    参考： srg.c SRG(shift register generater) Max length connection
          Ver. 1.0 (c) creamsoft org. 01/26/1993
          http://www.h4.dion.ne.jp/~ja5fp/creamsoft.html

    ビットパターンを全数計算して最長系列符号かどうかを調査している
    BCB　Ver5
*/
//---------------------------------------------------------------------------
#pragma argsused
int taps=-1;
char  calmode = 0;
FILE  *fp;
//----------------------------------------
short int ikutu0[256]  = {
  0,  1,  1,  2,  1,  2,  2,  3,  1,  2,  2,  3,  2,  3,  3,  4
};
short int ikutu[256];

inline void  init_ikutu(void)
{
  for(int n=16;  n<256;  n++)  {
    ikutu0[n] =  ikutu0[n & 0x0f] + ikutu0[n >> 4];
  }

  for(int n=0;  n<256;  n++)  {
    ikutu[n] =  ikutu0[n] % 2;
  }
}
//----------------------------------------
//最下位ビットにEXORしてくる
inline int exor(int  d)
{
  int er=0;
  for(int b=0;  b<sizeof(int);  b++)  {
    er ^= ikutu[d & 0xff];
    d >>= 8;
  }
  return  er;
}
//----------------------------------------
char *mem;
//----------------------------------------
//成功したら１　駄目なら０ tapが１のところをEXOR
int mtest(int bit,  int tap)
{
  int shiftreg = -1;
  int regmask = 1;  for(int i=1; i<bit; i++)  { regmask <<=1; regmask++;  }
  int mmax = (1 << bit)-2;
  int n,  nb;

  for(n=0;  n <mmax;  n++)  {
    nb = exor(shiftreg & regmask & tap);
    shiftreg <<= 1;     shiftreg |= nb;     shiftreg &= regmask;
    if(shiftreg==regmask) break;
  }
  return (n==mmax)? 1: 0;
}
//----------------------------------------
void  mfind(int mbit)
{
  init_ikutu();
  int nl=0, ns;
  int tap;

  if(taps>0)  {
  	printf("\n[%dbit %dtaps]\n", mbit,  taps);
   	fprintf(fp,"\n[%dbit %dtaps]\n", mbit,  taps);
  } else  {
	  printf("\n[%dbit]\n", mbit);
 	  fprintf(fp,"\n[%dbit]\n", mbit);
  }
//  int lc=0;
  int mtap = 1<<mbit; //pow(2, mbit);
  for(tap=(mtap>>1);  tap<mtap;  tap++)  {
    ns=0;
    int d=tap;
    for(int b=0;  b<sizeof(int);  b++)  {
      ns += ikutu0[d & 0xff];
      d >>= 8;
    }
    if(taps>0)  {
      if(ns != taps) continue;
    }
    if(ns & 1) continue;

    if(mtest(mbit, tap))  {
      if(++nl>7) {
        printf(" %X,\n", tap);   fprintf(fp, " %X,\n", tap);
        nl=0;
      } else  {
        printf(" %X,", tap);     fprintf(fp, " %X,", tap);
      }
    }
  }
}
//----------------------------------------
void  makeseq(int d, int s)
{
  if(d==0) return;
  //bit数を調べる
  int mtap = d;
  int mbit = 1;
  while((d=d>>1)!=0) mbit++;


  if(mbit>30) return;

  init_ikutu();
  if(mtest(mbit, mtap))  {
  //===
    int shiftreg = -1;
    int regmask = 1;  for(int i=1; i<mbit; i++)  { regmask <<=1; regmask++;  }
    int mmax = (1 << mbit)-1;
    int n,  nb;

    shiftreg = shiftreg << mbit;
    shiftreg = shiftreg ^ s;

    if(calmode=='a')  fprintf(fp, "SR=%dbit Mask=%X\n", mbit, mtap);

    int bl = 0;
    unsigned  char  bu;
    for(n=0;  n <mmax;  n++)  {
      nb = exor(shiftreg & regmask & mtap);
      if(calmode=='a')  {
        printf((nb)? "1" : "0");
        fprintf(fp, (nb)? "1\n" : "0\n");
      } else  {
        bu <<=1;  bu |= nb; bl++;
        if(bl==8)  {
          fwrite(&bu, 1,1, fp);  bl=0;
        }
      }
      shiftreg <<= 1;     shiftreg |= nb;     shiftreg &= regmask;
//      if(shiftreg==regmask) break;
    }
    if(calmode=='a')  {
      fprintf(fp, "1\n");
    } else  {
      bu<<=1;  fwrite(&bu, 1,1, fp);
    }
  } else  {
    return;
  }
}
//----------------------------------------
int main(int argc, char* argv[])
{
  int mbit, mask, startd = -1;
  char  *cp;
  printf("\
  M series generator.\n\
  Mathematical Assist Design Hal.T 2002/11/23 2004/01/27\n\
  Usage1 : mms [bit] [taps]   bit=3-30 taps=2-28 TAP search\n\
  Usage2 : mms -a HEX [START] HEX=MASK ASCII generator(default START=-1)\n\
  Usage3 : mms -b HEX         HEX=MASK BinaryBit generator (MSB->LSB)\n\
  ");

  if(argc==1) {
    return  -1;
  } else  {
    cp = argv[1];
    if(*cp=='-') {
      calmode = cp[1];
      if(argc <3) return  -1;
      if(argc >3) {
        sscanf(argv[3], "%X", &startd);
        if(startd==0) exit(-1);
      }
      if(sscanf(argv[2], "%X", &mask)==1) {
        char  fn[255];
        strcpy(fn, "m");  strcat(fn, argv[2]);

        if(calmode == 'a')  {
          strcat(fn, ".txt");   fp = fopen(fn, "wt");
        } else  {
          strcat(fn, ".bin");   fp = fopen(fn, "wb");
        }
        makeseq(mask, startd);
        fclose(fp);
      }
    } else  {
      mbit = atoi(argv[1]);
      if(mbit <3 || mbit > 30)  {
        return  -1;
      }
      if(argc>2)  {
        taps = atoi(argv[2]);
      }
      char  buf[256] = "mms";
      strcat(buf, argv[1]);
      if(argc>2)  { strcat(buf, "_"); strcat(buf, argv[2]); }
      strcat(buf, ".txt");

      fp = fopen(buf, "wt");
      mfind(mbit);
      fclose(fp);
    }
  }
  return 0;
}
//---------------------------------------------------------------------------