mul table

gistfile1.txt

         1   2   3   4   5   6   7   8   9
       --- --- --- --- --- --- --- --- ---
  1 |    1   2   3   4   5   6   7   8   9
  2 |    2   4   6   8  10  12  14  16  18
  3 |    3   6   9  12  15  18  21  24  27
  4 |    4   8  12  16  20  24  28  32  36
  5 |    5  10  15  20  25  30  35  41  45
  6 |    6  12  18  24  30  36  42  48  54
  7 |    7  14  21  28  35  42  49  56  63
  8 |    8  16  24  32  41  48  56  65  72
  9 |    9  18  27  36  45  54  63  72  81

multable.c

#include <stdio.h>
#include <math.h>

#define E 2.718281828459

#define LEN 128

int main(int argc, char *argv[])
{
    int i;
    unsigned short logTable[LEN]; // 8.8
    unsigned short eTable[256]; // 16.0

    memset(logTable, 0, sizeof(LEN));
    memset(eTable, 0, sizeof(eTable));

    for (i = 1; i < LEN; i++) {
        logTable[i] = log(i) * 256; // 8.8
    }

    for (i = 1; i < LEN; i++) {
        eTable[logTable[i] >> 3] = i; // pow(E, log(i)); // 16.0
    }

    int a, b;

    printf("      "); for (a = 1; a < 10; a++) printf("%t %3d", a); puts("");
    printf("      "); for (a = 1; a < 10; a++) printf("%t ---", a); puts("");

    for (a = 1; a < 10; a++) {
        printf("%3d | ", a);

        for (b = 1; b < 10; b++) {
            printf("%t %3d", eTable[(logTable[a] + logTable[b]) >> 3]);
        }

        puts("");
    }

    return 0;
}