/*

   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"

#define FUNCPTR_T gemm_fp

typedef void (*FUNCPTR_T)
     (
       doff_t  diagoffb,
       pack_t  schema_a,
       pack_t  schema_b,
       dim_t   m,
       dim_t   n,
       dim_t   k,
       void*   alpha1,
       void*   a, inc_t cs_a, dim_t pd_a, inc_t ps_a,
       void*   b, inc_t rs_b, dim_t pd_b, inc_t ps_b,
       void*   alpha2,
       void*   c, inc_t rs_c, inc_t cs_c,
       cntx_t* cntx,
       rntm_t* rntm,
       thrinfo_t* thread
     );

static FUNCPTR_T GENARRAY(ftypes,trsm_rl_ker_var2);


void bli_trsm_rl_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 );

	doff_t    diagoffb  = bli_obj_diag_offset( b );

	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 );

	void*     buf_a     = bli_obj_buffer_at_off( a );
	inc_t     cs_a      = bli_obj_col_stride( a );
	dim_t     pd_a      = bli_obj_panel_dim( a );
	inc_t     ps_a      = bli_obj_panel_stride( a );

	void*     buf_b     = bli_obj_buffer_at_off( b );
	inc_t     rs_b      = bli_obj_row_stride( b );
	dim_t     pd_b      = bli_obj_panel_dim( b );
	inc_t     ps_b      = bli_obj_panel_stride( b );

	void*     buf_c     = bli_obj_buffer_at_off( c );
	inc_t     rs_c      = bli_obj_row_stride( c );
	inc_t     cs_c      = bli_obj_col_stride( c );

	void*     buf_alpha1;
	void*     buf_alpha2;

	FUNCPTR_T f;

	// Grab the address of the internal scalar buffer for the scalar
	// attached to A (the non-triangular matrix). This will be the alpha
	// scalar used in the gemmtrsm subproblems (ie: the scalar that would
	// be applied to the packed copy of A prior to it being updated by
	// the trsm subproblem). This scalar may be unit, if for example it
	// was applied during packing.
	buf_alpha1 = bli_obj_internal_scalar_buffer( a );

	// Grab the address of the internal scalar buffer for the scalar
	// attached to C. This will be the "beta" scalar used in the gemm-only
	// subproblems that correspond to micro-panels that do not intersect
	// the diagonal. We need this separate scalar because it's possible
	// that the alpha attached to B was reset, if it was applied during
	// packing.
	buf_alpha2 = bli_obj_internal_scalar_buffer( c );

	// Index into the type combination array to extract the correct
	// function pointer.
	f = ftypes[dt_exec];

	// Invoke the function.
	f( diagoffb,
	   schema_a,
	   schema_b,
	   m,
	   n,
	   k,
	   buf_alpha1,
	   buf_a, cs_a, pd_a, ps_a,
	   buf_b, rs_b, pd_b, ps_b,
	   buf_alpha2,
	   buf_c, rs_c, cs_c,
	   cntx,
	   rntm,
	   thread );
}


#undef  GENTFUNC
#define GENTFUNC( ctype, ch, varname ) \
\
void PASTEMAC(ch,varname) \
     ( \
       doff_t  diagoffb, \
       pack_t  schema_a, \
       pack_t  schema_b, \
       dim_t   m, \
       dim_t   n, \
       dim_t   k, \
       void*   alpha1, \
       void*   a, inc_t cs_a, dim_t pd_a, inc_t ps_a, \
       void*   b, inc_t rs_b, dim_t pd_b, inc_t ps_b, \
       void*   alpha2, \
       void*   c, inc_t rs_c, inc_t cs_c, \
       cntx_t* cntx, \
       rntm_t* rntm, \
       thrinfo_t* thread  \
     ) \
{ \
	const num_t     dt          = PASTEMAC(ch,type); \
\
	/* 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; \
\
	/* Cast the micro-kernel address to its function pointer type. */ \
	/* NOTE: We use the upper-triangular gemmtrsm ukernel because, while
	   the current macro-kernel targets the "rl" case (right-side/lower-
	   triangular), it becomes upper-triangular after the kernel operation
	   is transposed so that all kernel instances are of the "left"
	   variety (since those are the only trsm ukernels that exist). */ \
	PASTECH(ch,gemmtrsm_ukr_ft) \
	               gemmtrsm_ukr = bli_cntx_get_l3_vir_ukr_dt( dt, BLIS_GEMMTRSM_U_UKR, cntx ); \
	PASTECH(ch,gemm_ukr_ft) \
	                   gemm_ukr = bli_cntx_get_l3_vir_ukr_dt( dt, BLIS_GEMM_UKR, cntx ); \
\
	/* 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. */ \
	ctype           ct[ BLIS_STACK_BUF_MAX_SIZE \
	                    / sizeof( ctype ) ] \
	                    __attribute__((aligned(BLIS_STACK_BUF_ALIGN_SIZE))); \
	const bool      col_pref    = bli_cntx_ukr_prefers_cols_dt( dt, BLIS_GEMM_VIR_UKR, cntx ); \
	const inc_t     rs_ct       = ( col_pref ? 1 : NR ); \
	const inc_t     cs_ct       = ( col_pref ? MR : 1 ); \
\
	ctype* restrict zero        = PASTEMAC(ch,0); \
	ctype* restrict minus_one   = PASTEMAC(ch,m1); \
	ctype* restrict a_cast      = a; \
	ctype* restrict b_cast      = b; \
	ctype* restrict c_cast      = c; \
	ctype* restrict alpha1_cast = alpha1; \
	ctype* restrict alpha2_cast = alpha2; \
	ctype* restrict b1; \
	ctype* restrict c1; \
\
	doff_t          diagoffb_j; \
	dim_t           k_full; \
	dim_t           m_iter, m_left; \
	dim_t           n_iter, n_left; \
	dim_t           m_cur; \
	dim_t           n_cur; \
	dim_t           k_b1121; \
	dim_t           k_b11; \
	dim_t           k_b21; \
	dim_t           off_b11; \
	dim_t           off_b21; \
	dim_t           i, j, jb; \
	inc_t           rstep_a; \
	inc_t           cstep_b; \
	inc_t           rstep_c, cstep_c; \
	inc_t           istep_a; \
	inc_t           istep_b; \
	inc_t           off_scl; \
	inc_t           ss_b_num; \
	inc_t           ss_b_den; \
	inc_t           ps_b_cur; \
	inc_t           is_b_cur; \
	auxinfo_t       aux; \
\
	/*
	   Assumptions/assertions:
	     rs_a == 1
	     cs_a == PACKNR
	     pd_a == NR
	     ps_a == stride to next micro-panel of A
	     rs_b == PACKMR
	     cs_b == 1
	     pd_b == MR
	     ps_b == stride to next micro-panel of B
	     rs_c == (no assumptions)
	     cs_c == (no assumptions)

	  Note that MR/NR and PACKMR/PACKNR have been swapped to reflect the
	  swapping of values in the control tree (ie: those values used when
	  packing). This swapping is needed since we cast right-hand trsm in
	  terms of transposed left-hand trsm. So, if we're going to be
	  transposing the operation, then A needs to be packed with NR and B
	  needs to be packed with MR (remember: B is the triangular matrix in
	  the right-hand side parameter case).
	*/ \
\
	/* Safety trap: Certain indexing within this macro-kernel does not
	   work as intended if both MR and NR are odd. */ \
	if ( ( bli_is_odd( PACKMR ) && bli_is_odd( NR ) ) || \
	     ( bli_is_odd( PACKNR ) && bli_is_odd( MR ) ) ) bli_abort(); \
\
	/* If any dimension is zero, return immediately. */ \
	if ( bli_zero_dim3( m, n, k ) ) return; \
\
	/* Safeguard: If the current panel of B is entirely above its diagonal,
	   it is implicitly zero. So we do nothing. */ \
	if ( bli_is_strictly_above_diag_n( diagoffb, k, n ) ) return; \
\
	/* Compute k_full as k inflated up to a multiple of NR. This is
	   needed because some parameter combinations of trsm reduce k
	   to advance past zero regions in the triangular matrix, and
	   when computing the imaginary stride of B (the non-triangular
	   matrix), which is used by 4m1/3m1 implementations, we need
	   this unreduced value of k. */ \
	k_full = ( k % NR != 0 ? k + NR - ( k % NR ) : k ); \
\
	/* Compute indexing scaling factor for for 4m or 3m. This is
	   needed because one of the packing register blocksizes (PACKMR
	   or PACKNR) is used to index into the micro-panels of the non-
	   triangular matrix when computing with a diagonal-intersecting
	   micro-panel of the triangular matrix. In the case of 4m or 3m,
	   real values are stored in both sub-panels, and so the indexing
	   needs to occur in units of real values. The value computed
	   here is divided into the complex pointer offset to cause the
	   pointer to be advanced by the correct value. */ \
	if ( bli_is_4mi_packed( schema_b ) || \
	     bli_is_3mi_packed( schema_b ) || \
	     bli_is_rih_packed( schema_b ) ) off_scl = 2; \
	else                                 off_scl = 1; \
\
	/* Compute the storage stride scaling. Usually this is just 1.
	   However, in the case of interleaved 3m, we need to scale the
	   offset by 3/2. Note that real-only, imag-only, and summed-only
	   packing formats are not applicable here since trsm is a two-
	   operand operation only (unlike trmm, which is capable of three-
	   operand). */ \
	if ( bli_is_3mi_packed( schema_b ) ) { ss_b_num = 3; ss_b_den = 2; } \
	else                                 { ss_b_num = 1; ss_b_den = 1; } \
\
	/* If there is a zero region above where the diagonal of B intersects
	   the left edge of the panel, adjust the pointer to A and treat this
	   case as if the diagonal offset were zero. Note that we don't need to
	   adjust the pointer to B since packm would have simply skipped over
	   the region that was not stored. */ \
	if ( diagoffb < 0 ) \
	{ \
		j        = -diagoffb; \
		k        = k - j; \
		diagoffb = 0; \
		a_cast   = a_cast + ( j * PACKMR ) / off_scl; \
	} \
\
	/* If there is a zero region to the right of where the diagonal
	   of B intersects the bottom of the panel, shrink it so that
	   we can index to the correct place in C (corresponding to the
	   part of the panel of B that was packed).
	   NOTE: This is NOT being done to skip over "no-op" iterations,
	   as with the trsm_lu macro-kernel. This MUST be done for correct
	   execution because we use n (via n_iter) to compute diagonal and
	   index offsets for backwards movement through B. */ \
	if ( diagoffb + k < n ) \
	{ \
		n = diagoffb + k; \
	} \
\
	/* Check the k dimension, which needs to be a multiple of NR. If k
	   isn't a multiple of NR, we adjust it higher to satisfy the micro-
	   kernel, which is expecting to perform an NR x NR triangular solve.
	   This adjustment of k is consistent with what happened when B was
	   packed: all of its bottom/right edges were zero-padded, and
	   furthermore, the panel that stores the bottom-right corner of the
	   matrix has its diagonal extended into the zero-padded region (as
	   identity). This allows the trsm of that bottom-right panel to
	   proceed without producing any infs or NaNs that would infect the
	   "good" values of the corresponding block of A. */ \
	if ( k % NR != 0 ) k += NR - ( k % NR ); \
\
	/* NOTE: We don't need to check that n is a multiple of PACKNR since we
	   know that the underlying buffer was already allocated to have an n
	   dimension that is a multiple of PACKNR, with the region between the
	   last column and the next multiple of NR zero-padded accordingly. */ \
\
	/* Clear the temporary C buffer in case it has any infs or NaNs. */ \
	PASTEMAC(ch,set0s_mxn)( MR, NR, \
	                        ct, rs_ct, cs_ct ); \
\
	/* Compute number of primary and leftover components of the m and n
       dimensions. */ \
	n_iter = n / NR; \
	n_left = n % NR; \
\
	m_iter = m / MR; \
	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. */ \
	rstep_a = ps_a; \
\
	cstep_b = ps_b; \
\
	rstep_c = rs_c * MR; \
	cstep_c = cs_c * NR; \
\
	istep_a = PACKMR * k_full; \
	istep_b = PACKNR * k; \
\
	if ( bli_is_odd( istep_a ) ) istep_a += 1; \
	if ( bli_is_odd( istep_b ) ) istep_b += 1; \
\
	/* Save the pack schemas of A and B to the auxinfo_t object.
	   NOTE: We swap the values for A and B since the triangular
	   "A" matrix is actually contained within B. */ \
	bli_auxinfo_set_schema_a( schema_b, &aux ); \
	bli_auxinfo_set_schema_b( schema_a, &aux ); \
\
	/* Save the imaginary stride of A to the auxinfo_t object.
	   NOTE: We swap the values for A and B since the triangular
	   "A" matrix is actually contained within B. */ \
	bli_auxinfo_set_is_b( istep_a, &aux ); \
\
	b1 = b_cast; \
	c1 = c_cast; \
\
	/* Loop over the n dimension (NR columns at a time). */ \
	for ( jb = 0; jb < n_iter; ++jb ) \
	{ \
		ctype* restrict a1; \
		ctype* restrict c11; \
		ctype* restrict b11; \
		ctype* restrict b21; \
		ctype* restrict b2; \
\
		j          = n_iter - 1 - jb; \
		diagoffb_j = diagoffb - ( doff_t )j*NR; \
		a1         = a_cast; \
		c11        = c1 + (n_iter-1)*cstep_c; \
\
		n_cur = ( bli_is_not_edge_b( jb, n_iter, n_left ) ? NR : n_left ); \
\
		/* Initialize our next panel of B to be the current panel of B. */ \
		b2 = b1; \
\
		/* If the current panel of B intersects the diagonal, use a
		   special micro-kernel that performs a fused gemm and trsm.
		   If the current panel of B resides below the diagonal, use a
		   a regular gemm micro-kernel. Otherwise, if it is above the
		   diagonal, it was not packed (because it is implicitly zero)
		   and so we do nothing. */ \
		if ( bli_intersects_diag_n( diagoffb_j, k, NR ) ) \
		{ \
			/* Determine the offset to and length of the panel that was packed
			   so we can index into the corresponding location in A. */ \
			off_b11   = bli_max( -diagoffb_j, 0 ); \
			k_b1121   = k - off_b11; \
			k_b11     = NR; \
			k_b21     = k_b1121 - NR; \
			off_b21   = off_b11 + k_b11; \
\
			/* Compute the addresses of the triangular block B11 and the
			   panel B21. */ \
			b11       = b1; \
			/* b21 = b1 + ( k_b11 * PACKNR ) / off_scl; */ \
			b21 = bli_ptr_inc_by_frac( b1, sizeof( ctype ), k_b11 * PACKNR, off_scl ); \
\
			/* Compute the panel stride for the current micro-panel. */ \
			is_b_cur  = k_b1121 * PACKNR; \
			is_b_cur += ( bli_is_odd( is_b_cur ) ? 1 : 0 ); \
			ps_b_cur  = ( is_b_cur * ss_b_num ) / ss_b_den; \
\
			/* Save the 4m1/3m1 imaginary stride of B to the auxinfo_t
			   object.
			   NOTE: We swap the values for A and B since the triangular
			   "A" matrix is actually contained within B. */ \
			bli_auxinfo_set_is_a( is_b_cur, &aux ); \
\
			/* Loop over the m dimension (MR rows at a time). */ \
			for ( i = 0; i < m_iter; ++i ) \
			{ \
				if( bli_trsm_my_iter( i, thread ) ){ \
\
				ctype* restrict a11; \
				ctype* restrict a12; \
				ctype* restrict a2; \
\
				m_cur = ( bli_is_not_edge_f( i, m_iter, m_left ) ? MR : m_left ); \
\
				/* Compute the addresses of the A11 block and A12 panel. */ \
				a11  = a1 + ( off_b11 * PACKMR ) / off_scl; \
				a12  = a1 + ( off_b21 * PACKMR ) / off_scl; \
\
				/* Compute the addresses of the next panels of A and B. */ \
				a2 = a1; \
				/*if ( bli_is_last_iter( i, m_iter, 0, 1 ) ) */\
				if ( i + bli_thrinfo_num_threads(thread) >= m_iter ) \
				{ \
					a2 = a_cast; \
					b2 = b1 + ps_b_cur; \
					if ( bli_is_last_iter( jb, n_iter, 0, 1 ) ) \
						b2 = b_cast; \
				} \
\
				/* Save addresses of next panels of A and B to the auxinfo_t
				   object. NOTE: We swap the values for A and B since the
				   triangular "A" matrix is actually contained within B. */ \
				bli_auxinfo_set_next_a( b2, &aux ); \
				bli_auxinfo_set_next_b( a2, &aux ); \
\
				/* Handle interior and edge cases separately. */ \
				if ( m_cur == MR && n_cur == NR ) \
				{ \
					/* Invoke the fused gemm/trsm micro-kernel. */ \
					gemmtrsm_ukr \
					( \
					  k_b21, \
					  alpha1_cast, \
					  b21, \
					  b11, \
					  a12, \
					  a11, \
					  c11, cs_c, rs_c, \
					  &aux, \
					  cntx  \
					); \
				} \
				else \
				{ \
					/* Invoke the fused gemm/trsm micro-kernel. */ \
					gemmtrsm_ukr \
					( \
					  k_b21, \
					  alpha1_cast, \
					  b21, \
					  b11, \
					  a12, \
					  a11, \
					  ct, cs_ct, rs_ct, \
					  &aux, \
					  cntx  \
					); \
\
					/* Copy the result to the bottom edge of C. */ \
					PASTEMAC(ch,copys_mxn)( m_cur, n_cur, \
					                        ct,  rs_ct, cs_ct, \
					                        c11, rs_c,  cs_c ); \
				} \
				} \
\
				a1  += rstep_a; \
				c11 += rstep_c; \
			} \
\
			b1 += ps_b_cur; \
		} \
		else if ( bli_is_strictly_below_diag_n( diagoffb_j, k, NR ) ) \
		{ \
			/* Save the 4m1/3m1 imaginary stride of B to the auxinfo_t
			   object.
			   NOTE: We swap the values for A and B since the triangular
			   "A" matrix is actually contained within B. */ \
			bli_auxinfo_set_is_a( istep_b, &aux ); \
\
			/* Loop over the m dimension (MR rows at a time). */ \
			for ( i = 0; i < m_iter; ++i ) \
			{ \
				if( bli_trsm_my_iter( i, thread ) ){ \
\
				ctype* restrict a2; \
\
				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. */ \
				a2 = a1; \
				/*if ( bli_is_last_iter( i, m_iter, 0, 1 ) ) */\
				if ( i + bli_thrinfo_num_threads(thread) >= m_iter ) \
				{ \
					a2 = a_cast; \
					b2 = b1 + cstep_b; \
					if ( bli_is_last_iter( jb, n_iter, 0, 1 ) ) \
						b2 = b_cast; \
				} \
\
				/* Save addresses of next panels of A and B to the auxinfo_t
				   object. NOTE: We swap the values for A and B since the
				   triangular "A" matrix is actually contained within B. */ \
				bli_auxinfo_set_next_a( b2, &aux ); \
				bli_auxinfo_set_next_b( a2, &aux ); \
\
				/* Handle interior and edge cases separately. */ \
				if ( m_cur == MR && n_cur == NR ) \
				{ \
					/* Invoke the gemm micro-kernel. */ \
					gemm_ukr \
					( \
					  k, \
					  minus_one, \
					  b1, \
					  a1, \
					  alpha2_cast, \
					  c11, cs_c, rs_c, \
					  &aux, \
					  cntx  \
					); \
				} \
				else \
				{ \
					/* Invoke the gemm micro-kernel. */ \
					gemm_ukr \
					( \
					  k, \
					  minus_one, \
					  b1, \
					  a1, \
					  zero, \
					  ct, cs_ct, rs_ct, \
					  &aux, \
					  cntx  \
					); \
\
					/* Add the result to the edge of C. */ \
					PASTEMAC(ch,xpbys_mxn)( m_cur, n_cur, \
					                        ct,  rs_ct, cs_ct, \
					                        alpha2_cast, \
					                        c11, rs_c,  cs_c ); \
				} \
				} \
\
				a1  += rstep_a; \
				c11 += rstep_c; \
			} \
\
			b1 += cstep_b; \
		} \
\
		c1 -= cstep_c; \
	} \
}

INSERT_GENTFUNC_BASIC0( trsm_rl_ker_var2 )

