starpu-max/examples/basic_examples/vector_scal_cpu_template.h

/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2010, 2011, 2012  CNRS
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

/*
 * This example complements vector_scal.c: here we implement a CPU version.
 */

#ifndef __VECTOR_SCAL_CPU_TEMPLATE_H__
#define __VECTOR_SCAL_CPU_TEMPLATE_H__

#include <starpu.h>
#ifdef __SSE__
#include <xmmintrin.h>
#endif

/* This kernel takes a buffer and scales it by a constant factor */
#define VECTOR_SCAL_CPU_FUNC(func_name)                                        \
void func_name(void *buffers[], void *cl_arg)                                  \
{                                                                              \
	unsigned i;                                                            \
	float *factor = (float *) cl_arg;                                      \
                                                                               \
	/*                                                                     \
	 * The "buffers" array matches the task->handles array: for instance   \
	 * task->handles[0] is a handle that corresponds to a data with        \
	 * vector "interface", so that the first entry of the array in the     \
	 * codelet  is a pointer to a structure describing such a vector (ie.  \
	 * struct starpu_vector_interface *). Here, we therefore manipulate    \
	 * the buffers[0] element as a vector: nx gives the number of elements \
	 * in the array, ptr gives the location of the array (that was possibly \
	 * migrated/replicated), and elemsize gives the size of each elements.  \
	 */                                                                    \
                                                                               \
	struct starpu_vector_interface *vector = (struct starpu_vector_interface *) buffers[0]; \
                                                                               \
	/* length of the vector */                                             \
	unsigned n = STARPU_VECTOR_GET_NX(vector);                             \
                                                                               \
	/* get a pointer to the local copy of the vector : note that we have to \
	 * cast it in (float *) since a vector could contain any type of       \
	 * elements so that the .ptr field is actually a uintptr_t */          \
	float *val = (float *)STARPU_VECTOR_GET_PTR(vector);                   \
                                                                               \
	/* scale the vector */                                                 \
	for (i = 0; i < n; i++)                                                \
		val[i] *= *factor;                                             \
}

#ifdef __SSE__
#define VECTOR_SCAL_SSE_FUNC(func_name)                                        \
void func_name(void *buffers[], void *cl_arg)                                  \
{                                                                              \
	float *vector = (float *) STARPU_VECTOR_GET_PTR(buffers[0]);           \
	unsigned int n = STARPU_VECTOR_GET_NX(buffers[0]);                     \
	unsigned int n_iterations = n/4;                                       \
                                                                               \
	__m128 *VECTOR = (__m128*) vector;                                     \
	__m128 FACTOR STARPU_ATTRIBUTE_ALIGNED(16);                            \
	float factor = *(float *) cl_arg;                                      \
	FACTOR = _mm_set1_ps(factor);                                          \
                                                                               \
	unsigned int i;	                                                       \
	for (i = 0; i < n_iterations; i++)                                     \
		VECTOR[i] = _mm_mul_ps(FACTOR, VECTOR[i]);                     \
                                                                               \
	unsigned int remainder = n%4;                                          \
	if (remainder != 0)                                                    \
	{                                                                      \
		unsigned int start = 4 * n_iterations;                         \
		for (i = start; i < start+remainder; ++i)                      \
		{                                                              \
			vector[i] = factor * vector[i];                        \
		}                                                              \
	}                                                                      \
}
#else /* !__SSE__ */
#define VECTOR_SCAL_SSE_FUNC(func_name)
#endif /* !__SSE__ */

#endif /* !__VECTOR_SCAL_CPU_TEMPLATE_H__ */