/*

   BLIS
   An object-based framework for developing high-performance BLAS-like
   libraries.

   Copyright (C) 2014, The University of Texas at Austin
   Copyright (C) 2018 - 2019, Advanced Micro Devices, Inc.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are
   met:
    - Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    - 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 distribution.
    - Neither the name(s) of the copyright holder(s) nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#include "blis.h"

typedef void (*xpbys_mxn_vft)
    (
      dim_t m,
      dim_t n,
      void* x, inc_t rs_x, inc_t cs_x,
      void* b,
      void* y, inc_t rs_y, inc_t cs_y
    );

#undef GENTFUNC2
#define GENTFUNC2(ctypex,ctypey,chx,chy,op) \
\
void PASTEMAC2(chx,chy,op) \
    ( \
      dim_t m, \
      dim_t n, \
      void* x, inc_t rs_x, inc_t cs_x, \
      void* b, \
      void* y, inc_t rs_y, inc_t cs_y \
    ) \
{ \
	ctypex* restrict x_cast = x; \
	ctypey* restrict b_cast = b; \
	ctypey* restrict y_cast = y; \
\
	PASTEMAC3(chx,chy,chy,xpbys_mxn) \
	( \
	  m, n, \
	  x_cast, rs_x, cs_x, \
	  b_cast, \
	  y_cast, rs_y,  cs_y \
	); \
}

INSERT_GENTFUNC2_BASIC0(xbpys_mxn_fn);
INSERT_GENTFUNC2_MIXDP0(xbpys_mxn_fn);

static xpbys_mxn_vft GENARRAY2_ALL(xbpys_mxn, xbpys_mxn_fn);


void bli_gemm_ker_var2
     (
       obj_t*  a,
       obj_t*  b,
       obj_t*  c,
       cntx_t* cntx,
       rntm_t* rntm,
       cntl_t* cntl,
       thrinfo_t* thread
     )
{
	num_t     dt_exec   = bli_obj_exec_dt( c );
	num_t     dt_c      = bli_obj_dt( c );

	pack_t    schema_a  = bli_obj_pack_schema( a );
	pack_t    schema_b  = bli_obj_pack_schema( b );

	dim_t     m         = bli_obj_length( c );
	dim_t     n         = bli_obj_width( c );
	dim_t     k         = bli_obj_width( a );

	char*     a_cast    = bli_obj_buffer_at_off( a );
	inc_t     is_a      = bli_obj_imag_stride( a );
	dim_t     pd_a      = bli_obj_panel_dim( a );
	inc_t     ps_a      = bli_obj_panel_stride( a );

	char*     b_cast    = bli_obj_buffer_at_off( b );
	inc_t     is_b      = bli_obj_imag_stride( b );
	dim_t     pd_b      = bli_obj_panel_dim( b );
	inc_t     ps_b      = bli_obj_panel_stride( b );

	char*     c_cast    = bli_obj_buffer_at_off( c );
	inc_t     rs_c      = bli_obj_row_stride( c );
	inc_t     cs_c      = bli_obj_col_stride( c );

	// If any dimension is zero, return immediately.
	if ( bli_zero_dim3( m, n, k ) ) return;

	// Detach and multiply the scalars attached to A and B.
	// NOTE: We know that the internal scalars of A and B are already of the
	// target datatypes because the necessary typecasting would have already
	// taken place during bli_packm_init().
	obj_t     scalar_a;
	obj_t     scalar_b;
	bli_obj_scalar_detach( a, &scalar_a );
	bli_obj_scalar_detach( b, &scalar_b );
	bli_mulsc( &scalar_a, &scalar_b );

	// Grab the addresses of the internal scalar buffers for the scalar
	// merged above and the scalar attached to C.
	// NOTE: We know that scalar_b is of type dt_exec due to the above code
	// that casts the scalars of A and B to dt_exec via scalar_a and scalar_b,
	// and we know that the internal scalar in C is already of the type dt_c
	// due to the casting in the implementation of bli_obj_scalar_attach().
	char* alpha_cast = bli_obj_internal_scalar_buffer( &scalar_b );
	char* beta_cast  = bli_obj_internal_scalar_buffer( c );

	// If 1m is being employed on a column- or row-stored matrix with a
	// real-valued beta, we can use the real domain macro-kernel, which
	// eliminates a little overhead associated with the 1m virtual
	// micro-kernel.
	// Only employ this optimization if the storage datatype of C is
	// equal to the execution/computation datatype.
#if 1
	if ( bli_cntx_method( cntx ) == BLIS_1M )
	{
		bli_gemm_ind_recast_1m_params
		(
		  &dt_exec,
		  &dt_c,
		  schema_a,
		  c,
		  &m, &n, &k,
		  &pd_a, &ps_a,
		  &pd_b, &ps_b,
		  &rs_c, &cs_c
		);
	}
#endif

#ifdef BLIS_ENABLE_GEMM_MD
	// Tweak parameters in select mixed domain cases (rcc, crc, ccr).
	if ( bli_cntx_method( cntx ) == BLIS_NAT )
	{
		bli_gemm_md_ker_var2_recast
		(
		  &dt_exec,
		  bli_obj_dt( a ),
		  bli_obj_dt( b ),
		  &dt_c,
		  &m, &n, &k,
		  &pd_a, &ps_a,
		  &pd_b, &ps_b,
		  c,
		  &rs_c, &cs_c
		);
	}
#endif

	siz_t        dt_size   = bli_dt_size( dt_exec );
	siz_t        dt_c_size = bli_dt_size( dt_c );

	// Alias some constants to simpler names.
	const dim_t  MR        = pd_a;
	const dim_t  NR        = pd_b;
	//const dim_t PACKMR     = cs_a;
	//const dim_t PACKNR     = rs_b;

	// Query the context for the micro-kernel address and cast it to its
	// function pointer type.
	gemm_ukr_vft gemm_ukr = bli_cntx_get_l3_vir_ukr_dt( dt_exec, BLIS_GEMM_UKR, cntx );

	// Query the params field from the obj_t. If it is non-NULL, grab the ukr
	// field of the params struct. If that function pointer is non-NULL, use it
	// as our microkernel instead of the default microkernel queried from the
	// cntx above.
	gemm_ker_params_t* params = bli_obj_ker_params( c );
	gemm_ukr_vft user_ukr = params ? params->ukr : NULL;
	if ( user_ukr ) gemm_ukr = user_ukr;

	// Temporary C buffer for edge cases. Note that the strides of this
	// temporary buffer are set so that they match the storage of the
	// original C matrix. For example, if C is column-stored, ct will be
	// column-stored as well.
	char        ct[ BLIS_STACK_BUF_MAX_SIZE ]
	                __attribute__((aligned(BLIS_STACK_BUF_ALIGN_SIZE)));
	const bool  col_pref    = bli_cntx_l3_vir_ukr_prefers_cols_dt( dt_exec, BLIS_GEMM_UKR, cntx );
	const inc_t rs_ct       = ( col_pref ? 1 : NR );
	const inc_t cs_ct       = ( col_pref ? MR : 1 );
	char*       zero        = bli_obj_buffer_for_const( dt_exec, &BLIS_ZERO );

	//
	// Assumptions/assertions:
	//   rs_a == 1
	//   cs_a == PACKMR
	//   pd_a == MR
	//   ps_a == stride to next micro-panel of A
	//   rs_b == PACKNR
	//   cs_b == 1
	//   pd_b == NR
	//   ps_b == stride to next micro-panel of B
	//   rs_c == (no assumptions)
	//   cs_c == (no assumptions)
	//

	// Compute number of primary and leftover components of the m and n
	// dimensions.
	dim_t n_iter = n / NR;
	dim_t n_left = n % NR;

	dim_t m_iter = m / MR;
	dim_t m_left = m % MR;

	if ( n_left ) ++n_iter;
	if ( m_left ) ++m_iter;

	// Determine some increments used to step through A, B, and C.
	inc_t rstep_a = ps_a * dt_size;

	inc_t cstep_b = ps_b * dt_size;

	inc_t rstep_c = rs_c * MR * dt_c_size;
	inc_t cstep_c = cs_c * NR * dt_c_size;

	auxinfo_t aux;

	// Save the pack schemas of A and B to the auxinfo_t object.
	bli_auxinfo_set_schema_a( schema_a, &aux );
	bli_auxinfo_set_schema_b( schema_b, &aux );

	// Save the imaginary stride of A and B to the auxinfo_t object.
	bli_auxinfo_set_is_a( is_a, &aux );
	bli_auxinfo_set_is_b( is_b, &aux );

	// Save the virtual microkernel address and the params.
	bli_auxinfo_set_ukr( gemm_ukr, &aux );
	bli_auxinfo_set_params( params, &aux );

	// The 'thread' argument points to the thrinfo_t node for the 2nd (jr)
	// loop around the microkernel. Here we query the thrinfo_t node for the
	// 1st (ir) loop around the microkernel.
	thrinfo_t* caucus = bli_thrinfo_sub_node( thread );

	// Query the number of threads and thread ids for each loop.
	dim_t jr_nt  = bli_thread_n_way( thread );
	dim_t jr_tid = bli_thread_work_id( thread );
	dim_t ir_nt  = bli_thread_n_way( caucus );
	dim_t ir_tid = bli_thread_work_id( caucus );

	dim_t jr_start, jr_end;
	dim_t ir_start, ir_end;
	dim_t jr_inc,   ir_inc;

	// Determine the thread range and increment for the 2nd and 1st loops.
	// NOTE: The definition of bli_thread_range_jrir() will depend on whether
	// slab or round-robin partitioning was requested at configure-time.
	bli_thread_range_jrir( thread, n_iter, 1, FALSE, &jr_start, &jr_end, &jr_inc );
	bli_thread_range_jrir( caucus, m_iter, 1, FALSE, &ir_start, &ir_end, &ir_inc );

	// Loop over the n dimension (NR columns at a time).
	for ( dim_t j = jr_start; j < jr_end; j += jr_inc )
	{
		char* b1 = b_cast + j * cstep_b;
		char* c1 = c_cast + j * cstep_c;

		dim_t n_cur = ( bli_is_not_edge_f( j, n_iter, n_left ) ? NR : n_left );

		// Initialize our next panel of B to be the current panel of B.
		char* b2 = b1;

		// Loop over the m dimension (MR rows at a time).
		for ( dim_t i = ir_start; i < ir_end; i += ir_inc )
		{
			char* a1  = a_cast + i * rstep_a;
			char* c11 = c1     + i * rstep_c;

			dim_t m_cur = ( bli_is_not_edge_f( i, m_iter, m_left ) ? MR : m_left );

			// Compute the addresses of the next panels of A and B.
			char* a2 = bli_gemm_get_next_a_upanel( a1, rstep_a, ir_inc );
			if ( bli_is_last_iter( i, ir_end, ir_tid, ir_nt ) )
			{
				a2 = a_cast;
				b2 = bli_gemm_get_next_b_upanel( b1, cstep_b, jr_inc );
				if ( bli_is_last_iter( j, jr_end, jr_tid, jr_nt ) )
					b2 = b_cast;
			}

			// Save addresses of next panels of A and B to the auxinfo_t
			// object.
			bli_auxinfo_set_next_a( a2, &aux );
			bli_auxinfo_set_next_b( b2, &aux );

			// Edge case handling now occurs within the microkernel itself, but
			// we must still explicitly accumulate to a temporary microtile in
			// situations where a virtual microkernel is being used, such as
			// during the 1m method or some cases of mixed datatypes.
			if ( dt_exec == dt_c )
			{
				// Invoke the gemm micro-kernel.
				gemm_ukr
				(
				  m_cur,
				  n_cur,
				  k,
				  alpha_cast,
				  a1,
				  b1,
				  beta_cast,
				  c11, rs_c, cs_c,
				  &aux,
				  cntx
				);
			}
			else
			{
				// Invoke the gemm micro-kernel.
				gemm_ukr
				(
				  MR,
				  NR,
				  k,
				  alpha_cast,
				  a1,
				  b1,
				  zero,
				  &ct, rs_ct, cs_ct,
				  &aux,
				  cntx
				);

				// Accumulate to C with type-casting.
				xbpys_mxn[ dt_exec ][ dt_c ]
				(
				    m_cur, n_cur,
				    &ct, rs_ct, cs_ct,
				    beta_cast,
				    c11, rs_c, cs_c
				);
			}
		}
	}

/*
PASTEMAC(ch,fprintm)( stdout, "gemm_ker_var2: b1", k, NR, b1, NR, 1, "%4.1f", "" );
PASTEMAC(ch,fprintm)( stdout, "gemm_ker_var2: a1", MR, k, a1, 1, MR, "%4.1f", "" );
PASTEMAC(ch,fprintm)( stdout, "gemm_ker_var2: c after", m_cur, n_cur, c11, rs_c, cs_c, "%4.1f", "" );
*/
}