source: buchla-68k/orig/BUCHLA/SHOWCG.C

/*
   =============================================================================
        showcg.c -- show the contents of a VSDD character generator table
        Version 10 -- 1988-01-26 -- D.N. Lynx Crowe
   =============================================================================
*/

#include "stdio.h"
#include "stddefs.h"

#define NPIXELS 8

#define NCHARS  0xE0

#include "cg2.c"

int     bitmask[] = {

        0x0001, 0x0002, 0x0004, 0x0008,
        0x0010, 0x0020, 0x0040, 0x0080,
        0x0100, 0x0200, 0x0400, 0x0800,
        0x1000, 0x2000, 0x4000, 0x8000
};

/* 
 */

/*
   =============================================================================
        bitrev(bitsin, nbits) -- reverse the rightmost nbits of bitsin.

        Any bits to the left of the reversed bits in the result will be zeros.
   =============================================================================
*/

int
bitrev(bitsin, nbits)
register int bitsin, nbits;
{
        register int    n, m;

        n = 0;

        for (m = 0; m < nbits; m++)
                if (bitsin & bitmask[m])
                        n |= bitmask[nbits-1-m];

        return(n);
}

/* 
 */

/*
   =============================================================================
        pbits(row, bits) -- print the bits in a row of a character
   =============================================================================
*/

pbits(row, bits)
register int row, bits;
{
        register int    j, k;

        k = bits;

        for (j = 0; j < NPIXELS; j++) {

                if (bits & 1)
                        putchar('*');
                else
                        putchar(' ');

                bits = bits >> 1;
        }

        bits = bitrev(k, NPIXELS);

        printf(" %1x %02x  ", row, bits);
}
                        
/* 
 */

main()
{
        register int    ch, irow, ich;

        for (ch = 0; ch < NCHARS; ch += 4) {

                printf("\n\n\t");

                for (ich = 0; ich < 4; ich++)
                        printf("Ch %03d/%02x/%03o  ", ch+ich, ch+ich, ch+ich);

                printf("\n\t");

                for (ich = 0; ich < 4; ich++)
                        printf("76543210   DA  ");

                printf("\n");

                for (irow = cg_rows - 1; irow GE 0; irow--) {

                        printf("\t");
                        pbits(irow, cgtable[irow][ch]);
                        pbits(irow, cgtable[irow][ch+1]);
                        pbits(irow, cgtable[irow][ch+2]);
                        pbits(irow, cgtable[irow][ch+3]);
                        printf("\n");
                }

                if ((ch & 0x0F) EQ 12)
                        printf("\f");
        }
}