#include <stdio.h>

extern void bcopy(void *src, void *dst, unsigned long cnt);

#define LEN 40  /* keep this below 255 */

void
shake (unsigned char *arry)
{
    int i;

    /* copy down - even aligned */
    bcopy (&arry[2], &arry[0], LEN - 2);
    printf("down - even-even\n");
    for (i = 0; i < 16; i++)
	printf("%3d ", arry[i]);
    printf("\n");

    /* copy up - even aligned */
    printf("up - even-even\n");
    bcopy (&arry[0], &arry[4], LEN - 4);
    for (i = 0; i < 16; i++)
	printf("%3d ", arry[i]);
    printf("\n");

    /* copy down - odd-even aligned */
    printf("down - even-odd\n");
    bcopy (&arry[8], &arry[1], LEN - 8);
    for (i = 0; i < 16; i++)
	printf("%3d ", arry[i]);
    printf("\n");
    
    /* copy up - odd-even aligned */
    printf("up - even-odd\n");
    bcopy (&arry[0], &arry[1], LEN - 1);
    for (i = 0; i < 16; i++)
	printf("%3d ", arry[i]);
    printf("\n");
    
    /* copy down - odd-odd aligned */
    printf("down - odd-odd\n");
    bcopy (&arry[7], &arry[1], LEN - 7);
    for (i = 0; i < 16; i++)
	printf("%3d ", arry[i]);
    printf("\n");
    
    /* copy up - odd-odd aligned */
    printf("up - odd-odd\n");
    bcopy (&arry[1], &arry[3], LEN - 3);
    for (i = 0; i < 16; i++)
	printf("%3d ", arry[i]);
    printf("\n");
}


int
main(int argc, char **argv)
{
    unsigned char bigo[0x20000];

    unsigned char ahull[LEN + 4], *arry;
    unsigned char bhull[LEN + 4], *brry;
    long i;
    int  k;

    for (i = 0; i < 0x20000; i++) {
	bigo[i] = i & 0xff;
    }
    /* shift bigo four positions up leaving the last */
    bcopy(&bigo[0], &bigo[4], (0x20000 - 5));

    for (i = 4 + 254 ; i < 0x20000 - 5; i += 0x100) {
	if (bigo[i] != 254 || bigo[i + 1] != 255) {
	    fprintf(stderr, "discrepancy on position %ld - got %u %u\n",
		    i, bigo[i], bigo[i + 1]);
	}
    }
    printf("the last one is %u\n", bigo[0x20000 - 1]);
    

    ahull[0] = ahull[1] = ahull[LEN + 2] = ahull[LEN + 3] = 0xff;
    bhull[0] = bhull[1] = bhull[LEN + 2] = bhull[LEN + 3] = 0xff;
    arry = &ahull[2];
    brry = &bhull[2];
    
    for (i = 0; i < LEN; i++) {
	arry[i] = i & 0xff;
    }

    /* test copying between disjoint regions */

    bcopy(&arry[0], &brry[0], LEN);
    for (i = 0; i < 16; i++)
	printf("%3d ", brry[i]);
    printf("\n");

    bcopy(&arry[1], &brry[1], LEN - 1);
    for (i = 0; i < 16; i++)
	printf("%3d ", brry[i]);
    printf("\n");

    bcopy(&arry[2], &brry[2], LEN - 2);
    for (i = 0; i < 16; i++)
	printf("%3d ", brry[i]);
    printf("\n");

    bcopy(&arry[3], &brry[3], LEN - 3);
    for (i = 0; i < 16; i++)
	printf("%3d ", brry[i]);
    printf("\n");

    for (k = 4; k < LEN; k++)
	bcopy(&arry[k], &brry[k], LEN - k);
    for (i = LEN-16 ; i < LEN; i++)
	printf("%3d ", brry[i]);
    printf("\n");
    for (i = 0; i < 16; i++)
	printf("%3d ", brry[i]);
    printf("\n");

    printf("*** %3d %3d %3d %3d ***\n",
	   ahull[0], ahull[1], ahull[LEN + 2], ahull[LEN + 3]);

    /* and now with an overlap */

    shake(&arry[0]);

    printf("*** %3d %3d %3d %3d ***\n",
	   ahull[0], ahull[1], ahull[LEN + 2], ahull[LEN + 3]);
    return 0;
}