Texas Instruments TMS320C64X manual DSPblkeswap16 Endian-Swap a Block of 16-Bit Values

DSP_blk_eswap16

DSP_blk_eswap16 Endian-Swap a Block of 16-Bit Values

Function	void blk_eswap16(void * restrict x, void * restrict r, int		nx)
Arguments	x [nx]	Source data. Must be double-word aligned.
	r [nx]	Destination array. Must be double-word aligned.
	nx	Number of 16-bit values to swap. Must be multiple of 8.
Description	The data in the x[] array is endian swapped, meaning that the byte-order of the
	bytes within each half-word of the r[] array is reversed. This facilitates moving
	big-endian data to a little-endian system or vice-versa.
	When the r pointer is non-NULL, the endian-swap occurs out-of-place, similar
	to a block move. When the r pointer is NULL, the endian-swap occurs in-place,
	allowing the swap to occur without using any additional storage.
Algorithm	This is the C equivalent of the assembly code without restrictions. Note that the
	assembly code is hand optimized and restrictions may apply.
	void DSP_blk_eswap16(void *x, void *r, int		nx)
	{
	int i;
	char *_x, *_r;

if (r)

{

_x = (char *)x; _r = (char *)r;

}else

{

_x = (char *)x; _r = (char *)r;

for (i = 0; i < nx; i++)

{

char t0, t1;

t0 = _x[i*2 + 1];

t1 = _x[i*2 + 0]; _r[i*2 + 0] = t0; _r[i*2 + 1] = t1;

}

}

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