OpenBLAS/kernel/arm64/dot.c

/***************************************************************************
Copyright (c) 2017, The OpenBLAS Project
Copyright (c) 2022, Arm Ltd
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#include "common.h"

// Some compilers will report feature support for SVE without the appropriate
// header available
#ifdef HAVE_SVE
#if defined __has_include 
#if __has_include(<arm_sve.h>) && __ARM_FEATURE_SVE
#define USE_SVE
#endif 
#endif
#endif

#ifdef USE_SVE
#include "dot_kernel_sve.c"
#endif
#include "dot_kernel_asimd.c"

#if defined(SMP)
extern int blas_level1_thread_with_return_value(int mode, BLASLONG m, BLASLONG n,
	BLASLONG k, void *alpha, void *a, BLASLONG lda, void *b, BLASLONG ldb,
	void *c, BLASLONG ldc, int (*function)(), int nthreads);
#endif

static RETURN_TYPE dot_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x, FLOAT *y, BLASLONG inc_y)
{
	RETURN_TYPE  dot = 0.0 ;

	if ( n <= 0 ) return dot;

#ifdef USE_SVE
	if (inc_x == 1 && inc_y == 1) {
		return dot_kernel_sve(n, x, y);
	}
#endif

	return dot_kernel_asimd(n, x, inc_x, y, inc_y);
}

#if defined(SMP)
static int dot_thread_function(BLASLONG n, BLASLONG dummy0,
	BLASLONG dummy1, FLOAT dummy2, FLOAT *x, BLASLONG inc_x, FLOAT *y,
	BLASLONG inc_y, FLOAT *result, BLASLONG dummy3)
{
	*(RETURN_TYPE *)result = dot_compute(n, x, inc_x, y, inc_y);

	return 0;
}
#endif

RETURN_TYPE CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x, FLOAT *y, BLASLONG inc_y)
{
#if defined(SMP)
	int nthreads;
	FLOAT dummy_alpha;
#endif
	RETURN_TYPE dot = 0.0;

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

	if (nthreads == 1) {
		dot = dot_compute(n, x, inc_x, y, inc_y);
	} else {
		int mode, i;
		char result[MAX_CPU_NUMBER * sizeof(double) * 2];
		RETURN_TYPE *ptr;

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

		blas_level1_thread_with_return_value(mode, n, 0, 0, &dummy_alpha,
				   x, inc_x, y, inc_y, result, 0,
				   ( void *)dot_thread_function, nthreads);

		ptr = (RETURN_TYPE *)result;
		for (i = 0; i < nthreads; i++) {
			dot = dot + (*ptr);
			ptr = (RETURN_TYPE *)(((char *)ptr) + sizeof(double) * 2);
		}
	}
#else
	dot = dot_compute(n, x, inc_x, y, inc_y);
#endif

	return dot;
}