OpenBLAS/kernel/arm/sum.c

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/**************************************************************************************
* trivial copy of asum.c with the ABS() removed                                       *
**************************************************************************************/

#include "common.h"
#include "../simd/intrin.h"
#include <math.h>

FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
{
	BLASLONG i = 0;
	FLOAT sumf = 0.0;
	if (n <= 0 || inc_x <= 0)
		return (sumf);
	n *= inc_x;
	if (inc_x == 1)
	{
#if V_SIMD && (!defined(DOUBLE) || (defined(DOUBLE) && V_SIMD_F64 && V_SIMD > 128))
#ifdef DOUBLE
		const int vstep = v_nlanes_f64;
		const int unrollx4 = n & (-vstep * 4);
		const int unrollx = n & -vstep;
		v_f64 vsum0 = v_zero_f64();
		v_f64 vsum1 = v_zero_f64();
		v_f64 vsum2 = v_zero_f64();
		v_f64 vsum3 = v_zero_f64();
		for (; i < unrollx4; i += vstep * 4)
		{
			vsum0 = v_add_f64(vsum0, v_loadu_f64(x + i));
			vsum1 = v_add_f64(vsum1, v_loadu_f64(x + i + vstep));
			vsum2 = v_add_f64(vsum2, v_loadu_f64(x + i + vstep * 2));
			vsum3 = v_add_f64(vsum3, v_loadu_f64(x + i + vstep * 3));
		}
		vsum0 = v_add_f64(
			v_add_f64(vsum0, vsum1), v_add_f64(vsum2, vsum3));
		for (; i < unrollx; i += vstep)
		{
			vsum0 = v_add_f64(vsum0, v_loadu_f64(x + i));
		}
		sumf = v_sum_f64(vsum0);
#else
		const int vstep = v_nlanes_f32;
		const int unrollx4 = n & (-vstep * 4);
		const int unrollx = n & -vstep;
		v_f32 vsum0 = v_zero_f32();
		v_f32 vsum1 = v_zero_f32();
		v_f32 vsum2 = v_zero_f32();
		v_f32 vsum3 = v_zero_f32();
		for (; i < unrollx4; i += vstep * 4)
		{
			vsum0 = v_add_f32(vsum0, v_loadu_f32(x + i));
			vsum1 = v_add_f32(vsum1, v_loadu_f32(x + i + vstep));
			vsum2 = v_add_f32(vsum2, v_loadu_f32(x + i + vstep * 2));
			vsum3 = v_add_f32(vsum3, v_loadu_f32(x + i + vstep * 3));
		}
		vsum0 = v_add_f32(
			v_add_f32(vsum0, vsum1), v_add_f32(vsum2, vsum3));
		for (; i < unrollx; i += vstep)
		{
			vsum0 = v_add_f32(vsum0, v_loadu_f32(x + i));
		}
		sumf = v_sum_f32(vsum0);
#endif
#else
		int n1 = n & -4;
		for (; i < n1; i += 4)
		{
			sumf += x[i] + x[i + 1] + x[i + 2] + x[i + 3];
		}
#endif
	}
	while (i < n)
	{
		sumf += x[i];
		i += inc_x;
	}
	return (sumf);
}