Any substitution for long long & in C?

"long long" is a register pair in the C6000 system.  Depending on what family you have (C6000, c64, c64+) you can do various optimizations on that register pair to increase your data throughput.  I didn't see this particular line in SPRU198, but I can get a _amem8() call to compile fine if I just declare a long long and use that variable for its return.  I haven't looked at the C type rules in forever, but my guess is that the & is used to address the contents of a register pair.  Maybe the TI folks can explain the semantics.

long long dar;

void *p = something;

dar = _amem8(p);

Sorry, It should be SPRUF30.

In A.22 section

/*---------------------------------------------------**
** This function performs subtraction of 2           **
** images. Each image consist of 8 bits per samples. **
**---------------------------------------------------*/
void IMG_sub_8
(
    char * restrict imgR1,   /* Image 1 read pointer */
    char * restrict imgR2,       /* Image 2 read pointer */
    char * restrict imgW,        /* Output image pointer */
    int count                /* Number of samples in image */
)
{
    int i;
    long long im1_p7_p6_p5_p4_p3_p2_p1_p0, im2_p7_p6_p5_p4_p3_p2_p1_p0;
    int im1_p7_p6_p5_p4, im1_p3_p2_p1_p0, im2_p7_p6_p5_p4, im2_p3_p2_p1_p0;
    int res_p7_p6_p5_p4, res_p3_p2_p1_p0;
    for (i = 0; i < count >> 4; i += 16) {
        im1_p7_p6_p5_p4_p3_p2_p1_p0 = _amem8(imgR1);
        im2_p7_p6_p5_p4_p3_p2_p1_p0 = _amem8(imgR2);
        imgR1 += 8;
        imgR2 += 8;
        im1_p3_p2_p1_p0 = _loll (im1_p7_p6_p5_p4_p3_p2_p1_p0);
        im1_p7_p6_p5_p4 = _hill (im1_p7_p6_p5_p4_p3_p2_p1_p0);
        im2_p3_p2_p1_p0 = _loll (im2_p7_p6_p5_p4_p3_p2_p1_p0);
        im2_p7_p6_p5_p4 = _hill (im2_p7_p6_p5_p4_p3_p2_p1_p0);
        res_p3_p2_p1_p0 = _sub4 (im1_p3_p2_p1_p0, im2_p3_p2_p1_p0);
        res_p7_p6_p5_p4 = _sub4 (im1_p7_p6_p5_p4, im2_p7_p6_p5_p4);
        _amem8(imgW) = _itoll (res_p7_p6_p5_p4, res_p3_p2_p1_p0);
        imgW += 8;
        im1_p7_p6_p5_p4_p3_p2_p1_p0 = _amem8(imgR1);
        im2_p7_p6_p5_p4_p3_p2_p1_p0 = _amem8(imgR2);
        imgR1 += 8;
        imgR2 += 8;
        im1_p3_p2_p1_p0 = _loll (im1_p7_p6_p5_p4_p3_p2_p1_p0);
        im1_p7_p6_p5_p4 = _hill (im1_p7_p6_p5_p4_p3_p2_p1_p0);
        im2_p3_p2_p1_p0 = _loll (im2_p7_p6_p5_p4_p3_p2_p1_p0);
        im2_p7_p6_p5_p4 = _hill (im2_p7_p6_p5_p4_p3_p2_p1_p0);
        res_p3_p2_p1_p0 = _sub4 (im1_p3_p2_p1_p0, im2_p3_p2_p1_p0);
        res_p7_p6_p5_p4 = _sub4 (im1_p7_p6_p5_p4, im2_p7_p6_p5_p4);
        _amem8(imgW) = _itoll (res_p7_p6_p5_p4, res_p3_p2_p1_p0);
        imgW += 8;
    }
}

I think this code can not be compiled using C compiler, because "_amem8" returns "long long &", we know that "Reference" can be used in C++ instead of C.  Could any experts tell me how to deal with it?

Thanks.

I think if I can get the address returned by "_amem8",  there will work well using C.

I mean:

if a function named "_amem8p" can return "long long *".

long long* p = 0;

p = _amem8p(imgW);

*p = _itoll (res_p7_p6_p5_p4, res_p3_p2_p1_p0);

It works.  Unfortunately I do not find any clues.