/***************************************************************************
Copyright (c) 2013-2016, The OpenBLAS Project
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modification, are permitted provided that the following conditions are
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1. Redistributions of source code must retain the above copyright
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2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
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its contributors may be used to endorse or promote products
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*****************************************************************************/

/**************************************************************************************
* 2016/03/30 Werner Saar (wernsaar@googlemail.com)
* 	 BLASTEST 		: OK
* 	 CTEST			: OK
* 	 TEST			: OK
*	 LAPACK-TEST		: OK
**************************************************************************************/



#include "common.h"


#if defined(POWER8) || defined(POWER9) || defined(POWER10)
#if defined(__VEC__) || defined(__ALTIVEC__)
#include "dgemv_n_microk_power8.c"
#endif
#endif


#define NBMAX 4096

#ifndef HAVE_KERNEL_4x4

static void dgemv_kernel_4x4(BLASLONG n, FLOAT *a_ptr, BLASLONG lda, FLOAT *xo, FLOAT *y, FLOAT alpha)
{
	BLASLONG i;
	FLOAT x[4]  __attribute__ ((aligned (16)));;
	FLOAT *a0 = a_ptr;
	FLOAT *a1 = a0 + lda;
	FLOAT *a2 = a1 + lda;
	FLOAT *a3 = a2 + lda;


	for ( i=0; i<4; i++)
		x[i] = xo[i] * alpha;

	for ( i=0; i< n; i+=4 )
	{
		y[i] += a0[i]*x[0] + a1[i]*x[1] + a2[i]*x[2] + a3[i]*x[3];		
		y[i+1] += a0[i+1]*x[0] + a1[i+1]*x[1] + a2[i+1]*x[2] + a3[i+1]*x[3];		
		y[i+2] += a0[i+2]*x[0] + a1[i+2]*x[1] + a2[i+2]*x[2] + a3[i+2]*x[3];		
		y[i+3] += a0[i+3]*x[0] + a1[i+3]*x[1] + a2[i+3]*x[2] + a3[i+3]*x[3];		
	}
}

#endif

#ifndef HAVE_KERNEL_4x2

static void dgemv_kernel_4x2(BLASLONG n, FLOAT *a0, FLOAT *a1, FLOAT *xo, FLOAT *y, FLOAT alpha)
{
	BLASLONG i;
	FLOAT x[4]  __attribute__ ((aligned (16)));;

	for ( i=0; i<2; i++)
		x[i] = xo[i] * alpha;

	for ( i=0; i< n; i+=4 )
	{
		y[i] += a0[i]*x[0] + a1[i]*x[1];		
		y[i+1] += a0[i+1]*x[0] + a1[i+1]*x[1];		
		y[i+2] += a0[i+2]*x[0] + a1[i+2]*x[1];		
		y[i+3] += a0[i+3]*x[0] + a1[i+3]*x[1];		
	}
}


#endif

#ifndef HAVE_KERNEL_4x1

static void dgemv_kernel_4x1(BLASLONG n, FLOAT *a0, FLOAT *xo, FLOAT *y, FLOAT alpha)
{
	BLASLONG i;
	FLOAT x[4]  __attribute__ ((aligned (16)));;

	for ( i=0; i<1; i++)
		x[i] = xo[i] * alpha;

	for ( i=0; i< n; i+=4 )
	{
		y[i] += a0[i]*x[0];		
		y[i+1] += a0[i+1]*x[0];		
		y[i+2] += a0[i+2]*x[0];		
		y[i+3] += a0[i+3]*x[0];		
	}
}


#endif


static void add_y(BLASLONG n, FLOAT *src, FLOAT *dest, BLASLONG inc_dest)
{
	BLASLONG i;
	if ( inc_dest != 1 )
	{
		for ( i=0; i<n; i++ )
		{
			*dest += *src;
			src++;
			dest += inc_dest;
		}
		return;
	}

}

int CNAME(BLASLONG m, BLASLONG n, BLASLONG dummy1, FLOAT alpha, FLOAT *a, BLASLONG lda, FLOAT *x, BLASLONG inc_x, FLOAT *y, BLASLONG inc_y, FLOAT *buffer)
{

	BLASLONG i;
	FLOAT *a_ptr;
	FLOAT *x_ptr;
	FLOAT *y_ptr;
	BLASLONG n1;
	BLASLONG m1;
	BLASLONG m2;
	BLASLONG m3;
	BLASLONG n2;
	BLASLONG lda4 =  lda << 2;
	FLOAT xbuffer[8] __attribute__ ((aligned (16)));
	FLOAT *ybuffer;

        if ( m < 1 ) return(0);
        if ( n < 1 ) return(0);

	ybuffer = buffer;
	
	n1 = n >> 2 ;
	n2 = n &  3 ;

        m3 = m & 3  ;
        m1 = m & -4 ;
        m2 = (m & (NBMAX-1)) - m3 ;

	y_ptr = y;

	BLASLONG NB = NBMAX;

	while ( NB == NBMAX )
	{
		
		m1 -= NB;
		if ( m1 < 0)
		{
			if ( m2 == 0 ) break;	
			NB = m2;
		}
		
		a_ptr = a;
		x_ptr = x;
		
		if ( inc_y != 1 )
			memset(ybuffer,0,NB*8);
		else
			ybuffer = y_ptr;

		if ( inc_x == 1 )
		{


			for( i = 0; i < n1 ; i++)
			{
				dgemv_kernel_4x4(NB,a_ptr,lda,x_ptr,ybuffer,alpha);
				a_ptr += lda4;
				x_ptr += 4;	
			}

			if ( n2 & 2 )
			{
				dgemv_kernel_4x2(NB,a_ptr,a_ptr+lda,x_ptr,ybuffer,alpha);
				a_ptr += lda*2;
				x_ptr += 2;	
			}


			if ( n2 & 1 )
			{
				dgemv_kernel_4x1(NB,a_ptr,x_ptr,ybuffer,alpha);
				a_ptr += lda;
				x_ptr += 1;	

			}


		}
		else
		{

			for( i = 0; i < n1 ; i++)
			{
				xbuffer[0] = x_ptr[0];
				x_ptr += inc_x;	
				xbuffer[1] =  x_ptr[0];
				x_ptr += inc_x;	
				xbuffer[2] =  x_ptr[0];
				x_ptr += inc_x;	
				xbuffer[3] = x_ptr[0];
				x_ptr += inc_x;	
				dgemv_kernel_4x4(NB,a_ptr,lda,xbuffer,ybuffer,alpha);
				a_ptr += lda4;
			}

			for( i = 0; i < n2 ; i++)
			{
				xbuffer[0] = x_ptr[0];
				x_ptr += inc_x;	
				dgemv_kernel_4x1(NB,a_ptr,xbuffer,ybuffer,alpha);
				a_ptr += lda;

			}

		}

		a     += NB;
		if ( inc_y != 1 )
		{
			add_y(NB,ybuffer,y_ptr,inc_y);
			y_ptr += NB * inc_y;
		}
		else
			y_ptr += NB ;

	}

	if ( m3 == 0 ) return(0);

	if ( m3 == 3 )
	{
		a_ptr = a;
		x_ptr = x;
		FLOAT temp0 = 0.0;
		FLOAT temp1 = 0.0;
		FLOAT temp2 = 0.0;
		if ( lda == 3 && inc_x ==1 )
		{

			for( i = 0; i < ( n & -4 ); i+=4 )
			{

				temp0 += a_ptr[0] * x_ptr[0] + a_ptr[3] * x_ptr[1];
				temp1 += a_ptr[1] * x_ptr[0] + a_ptr[4] * x_ptr[1];
				temp2 += a_ptr[2] * x_ptr[0] + a_ptr[5] * x_ptr[1];

				temp0 += a_ptr[6] * x_ptr[2] + a_ptr[9]  * x_ptr[3];
				temp1 += a_ptr[7] * x_ptr[2] + a_ptr[10] * x_ptr[3];
				temp2 += a_ptr[8] * x_ptr[2] + a_ptr[11] * x_ptr[3];

				a_ptr += 12;
				x_ptr += 4;
			}

			for( ; i < n; i++ )
			{
				temp0 += a_ptr[0] * x_ptr[0];
				temp1 += a_ptr[1] * x_ptr[0];
				temp2 += a_ptr[2] * x_ptr[0];
				a_ptr += 3;
				x_ptr ++;
			}

		}
		else
		{

			for( i = 0; i < n; i++ )
			{
				temp0 += a_ptr[0] * x_ptr[0];
				temp1 += a_ptr[1] * x_ptr[0];
				temp2 += a_ptr[2] * x_ptr[0];
				a_ptr += lda;
				x_ptr += inc_x;


			}

		}
		y_ptr[0] += alpha * temp0;
		y_ptr += inc_y;
		y_ptr[0] += alpha * temp1;
		y_ptr += inc_y;
		y_ptr[0] += alpha * temp2;
		return(0);
	}


	if ( m3 == 2 )
	{
		a_ptr = a;
		x_ptr = x;
		FLOAT temp0 = 0.0;
		FLOAT temp1 = 0.0;
		if ( lda == 2 && inc_x ==1 )
		{

			for( i = 0; i < (n & -4) ; i+=4 )
			{
				temp0 += a_ptr[0] * x_ptr[0] + a_ptr[2] * x_ptr[1];
				temp1 += a_ptr[1] * x_ptr[0] + a_ptr[3] * x_ptr[1];
				temp0 += a_ptr[4] * x_ptr[2] + a_ptr[6] * x_ptr[3];
				temp1 += a_ptr[5] * x_ptr[2] + a_ptr[7] * x_ptr[3];
				a_ptr += 8;
				x_ptr += 4;

			}


			for( ; i < n; i++ )
			{
				temp0 += a_ptr[0]   * x_ptr[0];
				temp1 += a_ptr[1]   * x_ptr[0];
				a_ptr += 2;
				x_ptr ++;
			}

		}
		else
		{

			for( i = 0; i < n; i++ )
			{
				temp0 += a_ptr[0] * x_ptr[0];
				temp1 += a_ptr[1] * x_ptr[0];
				a_ptr += lda;
				x_ptr += inc_x;


			}

		}
		y_ptr[0] += alpha * temp0;
		y_ptr += inc_y;
		y_ptr[0] += alpha * temp1;
		return(0);
	}

	if ( m3 == 1 )
	{
		a_ptr = a;
		x_ptr = x;
		FLOAT temp = 0.0;
		if ( lda == 1 && inc_x ==1 )
		{

			for( i = 0; i < (n & -4); i+=4 )
			{
				temp += a_ptr[i] * x_ptr[i] + a_ptr[i+1] * x_ptr[i+1] + a_ptr[i+2] * x_ptr[i+2] + a_ptr[i+3] * x_ptr[i+3];
	
			}

			for( ; i < n; i++ )
			{
				temp += a_ptr[i] * x_ptr[i];
			}

		}
		else
		{

			for( i = 0; i < n; i++ )
			{
				temp += a_ptr[0] * x_ptr[0];
				a_ptr += lda;
				x_ptr += inc_x;
			}

		}
		y_ptr[0] += alpha * temp;
		return(0);
	}


	return(0);
}


