/***************************************************************************
Copyright (c) 2017, The OpenBLAS Project
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modification, are permitted provided that the following conditions are
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its contributors may be used to endorse or promote products
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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*****************************************************************************/

#include "common.h"

#include <arm_neon.h>
#define	N	"x0"	/* vector length */
#define	X	"x1"	/* X vector address */
#define	INC_X	"x2"	/* X stride */
#define	Y	"x3"	/* Y vector address */
#define	INC_Y	"x4"	/* Y stride */
#define J	"x5"	/* loop variable */

/*******************************************************************************
* Macro definitions
*******************************************************************************/
#if !defined(COMPLEX)
#if !defined(DOUBLE)
#define TMPF		"s0"
#define INC_SHIFT	"2"
#define N_DIV_SHIFT	"2"
#define N_REM_MASK	"3"
#else
#define TMPF		"d0"
#define INC_SHIFT	"3"
#define N_DIV_SHIFT	"1"
#define N_REM_MASK	"1"
#endif
#else
#if !defined(DOUBLE)
#define TMPF		"d0"
#define INC_SHIFT	"3"
#define N_DIV_SHIFT	"1"
#define N_REM_MASK	"1"
#else
#define TMPF		"q0"
#define INC_SHIFT	"4"
#define N_DIV_SHIFT	"0"
#define N_REM_MASK	"0"
#endif
#endif

#define KERNEL_F1					\
	"ldr	"TMPF", ["X"]			\n"	\
	"add	"X", "X", "INC_X"		\n"	\
	"str	"TMPF", ["Y"]			\n"	\
	"add	"Y", "Y", "INC_Y"		\n"

#define KERNEL_F					\
	"ldr	q0, ["X"], #16			\n"	\
	"str	q0, ["Y"], #16			\n"

#define INIT						\
	"lsl	"INC_X", "INC_X", #"INC_SHIFT"	\n"	\
	"lsl	"INC_Y", "INC_Y", #"INC_SHIFT"	\n"


static int do_copy(BLASLONG n, FLOAT *x, BLASLONG inc_x, FLOAT *y, BLASLONG inc_y)
{
	if ( n < 0 )  return 0;

	__asm__ __volatile__ (
	"	mov	"N", %[N_]			\n"
	"	mov	"X", %[X_]			\n"
	"	mov	"INC_X", %[INCX_]		\n"
	"	mov	"Y", %[Y_]			\n"
	"	mov	"INC_Y", %[INCY_]		\n"
	"	cmp	"N", xzr			\n"
	"	ble	8f //copy_kernel_L999		\n"
	"	cmp	"INC_X", #1			\n"
	"	bne	4f //copy_kernel_S_BEGIN	\n"
	"	cmp	"INC_Y", #1			\n"
	"	bne	4f //copy_kernel_S_BEGIN	\n"

	"// .Lcopy_kernel_F_BEGIN:			\n"
	"	"INIT"					\n"
	"	asr	"J", "N", #"N_DIV_SHIFT"	\n"
	"	cmp	"J", xzr			\n"
	"	beq	2f //copy_kernel_F1		\n"
	"	.align 5				\n"

	"1: //copy_kernel_F:				\n"
	"	"KERNEL_F"				\n"
	"	subs	"J", "J", #1			\n"
	"	bne	1b //copy_kernel_F		\n"

	"2: //copy_kernel_F1:				\n"
#if defined(COMPLEX) && defined(DOUBLE)
	"	b	8f //copy_kernel_L999		\n"
#else
	"	ands	"J", "N", #"N_REM_MASK"		\n"
	"	ble	8f //copy_kernel_L999		\n"
#endif

	"3: //copy_kernel_F10:				\n"
	"	"KERNEL_F1"				\n"
	"	subs	"J", "J", #1			\n"
	"	bne	3b //copy_kernel_F10		\n"
	"	b	8f //copy_kernel_L999		\n"

	"4: //copy_kernel_S_BEGIN:			\n"
	"	"INIT"					\n"
	"	asr	"J", "N", #2			\n"
	"	cmp	"J", xzr			\n"
	"	ble	6f //copy_kernel_S1		\n"

	"5: //copy_kernel_S4:				\n"
	"	"KERNEL_F1"				\n"
	"	"KERNEL_F1"				\n"
	"	"KERNEL_F1"				\n"
	"	"KERNEL_F1"				\n"
	"	subs	"J", "J", #1			\n"
	"	bne	5b //copy_kernel_S4		\n"

	"6: //copy_kernel_S1:				\n"
	"	ands	"J", "N", #3			\n"
	"	ble	8f //copy_kernel_L999		\n"

	"7: //copy_kernel_S10:				\n"
	"	"KERNEL_F1"				\n"
	"	subs	"J", "J", #1			\n"
	"	bne	7b //copy_kernel_S10		\n"

	"8: //copy_kernel_L999:				\n"

	:
	: [N_]    "r"  (n),		//%1
	  [X_]    "r"  (x),		//%2
	  [INCX_] "r"  (inc_x),		//%3
	  [Y_]    "r"  (y),		//%4
	  [INCY_] "r"  (inc_y)		//%5
	: "cc",
	  "memory",
	  "x0", "x1", "x2", "x3", "x4", "x5",
	  "d0"
	);

	return 0;
}

#if defined(SMP)
static int copy_thread_function(BLASLONG n, BLASLONG dummy0,
	BLASLONG dummy1, FLOAT dummy2, FLOAT *x, BLASLONG inc_x, FLOAT *y,
	BLASLONG inc_y, FLOAT *dummy3, BLASLONG dummy4)
{
	do_copy(n, x, inc_x, y, inc_y);

	return 0;
}
#endif

int CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x, FLOAT *y, BLASLONG inc_y)
{
#if defined(SMP)
	int nthreads;
	FLOAT dummy_alpha;
#endif

	if (n <= 0) return 0;

#if defined(SMP)
	if (inc_x == 0 || n <= 10000)
		nthreads = 1;
	else
		nthreads = num_cpu_avail(1);

	if (nthreads == 1) {
		do_copy(n, x, inc_x, y, inc_y);
	} else {
		int mode = 0;

#if !defined(COMPLEX)
		mode = BLAS_REAL;
#else
		mode = BLAS_COMPLEX;
#endif
#if !defined(DOUBLE)
		mode |= BLAS_SINGLE;
#else
		mode |= BLAS_DOUBLE;
#endif

		blas_level1_thread(mode, n, 0, 0, &dummy_alpha,
				   x, inc_x, y, inc_y, NULL, 0,
				   ( void *)copy_thread_function, nthreads);
	}
#else
	do_copy(n, x, inc_x, y, inc_y);
#endif

	return 0;
}