SSE2NEON.h

#ifndef SSE2NEON_H
#define SSE2NEON_H

// This header file provides a simple API translation layer
// between SSE intrinsics to their corresponding ARM NEON versions
//
// This header file does not (yet) translate *all* of the SSE intrinsics.
// Since this is in support of a specific porting effort, I have only
// included the intrinsics I needed to get my port to work.
//
// Questions/Comments/Feedback send to: jratcliffscarab@gmail.com
//
// If you want to improve or add to this project, send me an
// email and I will probably approve your access to the depot.
//
// Project is located here:
//
//	https://code.google.com/p/sse2neon/
//
// TipJar: 1PzgWDSyq4pmdAXRH8SPUtta4SWGrt4B1p

#include "arm_neon.h"

/*******************************************************/
/* MACRO for shuffle parameter for _mm_shuffle_ps().   */
/* Argument fp3 is a digit[0123] that represents the fp*/
/* from argument "b" of mm_shuffle_ps that will be     */
/* placed in fp3 of result. fp2 is the same for fp2 in */
/* result. fp1 is a digit[0123] that represents the fp */
/* from argument "a" of mm_shuffle_ps that will be     */
/* places in fp1 of result. fp0 is the same for fp0 of */
/* result                                              */
/*******************************************************/
#define _MM_SHUFFLE(fp3,fp2,fp1,fp0) (((fp3) << 6) | ((fp2) << 4) | \
	((fp1) << 2) | ((fp0)))

typedef float32x4_t __m128;
typedef int32x4_t __m128i;

// ******************************************
// Set/get methods
// ******************************************

// Sets the 128-bit value to zero https://msdn.microsoft.com/en-us/library/vstudio/ys7dw0kh(v=vs.100).aspx
inline __m128i _mm_setzero_si128 ()
{
	return vdupq_n_s32(0);
}

// Clears the four single-precision, floating-point values. https://msdn.microsoft.com/en-us/library/vstudio/tk1t2tbz(v=vs.100).aspx
inline __m128 _mm_setzero_ps(void) 
{
	return vdupq_n_f32(0);
}

// Sets the four single-precision, floating-point values to w. https://msdn.microsoft.com/en-us/library/vstudio/2x1se8ha(v=vs.100).aspx
inline __m128 _mm_set1_ps(float _w) 
{
	return vdupq_n_f32(_w);
}

// Sets the four single-precision, floating-point values to the four inputs. https://msdn.microsoft.com/en-us/library/vstudio/afh0zf75(v=vs.100).aspx
inline __m128 _mm_set_ps(float w, float z , float y , float x ) 
{
	float __attribute__ ((aligned (16))) data[4] = { x, y, z, w };
	return vld1q_f32(data);
}

 // Sets the 4 signed 32-bit integer values to i. https://msdn.microsoft.com/en-us/library/vstudio/h4xscxat(v=vs.100).aspx
inline __m128i _mm_set1_epi32 (int _i)
{
	return vdupq_n_s32(_i);
}

// Sets the 4 signed 32-bit integer values. https://msdn.microsoft.com/en-us/library/vstudio/019beekt(v=vs.100).aspx
inline __m128i _mm_set_epi32 (int i3, int i2,int i1, int i0)
{
	int32_t __attribute__ ((aligned (16))) data[4] = { i0, i1, i2, i3 };
	return vld1q_s32(data);
}

// Stores four single-precision, floating-point values. https://msdn.microsoft.com/en-us/library/vstudio/s3h4ay6y(v=vs.100).aspx
inline void _mm_store_ps(float *p, __m128 a ) 
{
	vst1q_f32(p,a);
}

 // Loads a single single-precision, floating-point value, copying it into all four words https://msdn.microsoft.com/en-us/library/vstudio/5cdkf716(v=vs.100).aspx
inline __m128 _mm_load1_ps(const float * p )
{
	return vld1q_dup_f32(p);
}

 // Loads four single-precision, floating-point values. https://msdn.microsoft.com/en-us/library/vstudio/zzd50xxt(v=vs.100).aspx
inline __m128 _mm_load_ps(const float * p )
{
	return vld1q_f32(p);
}


// ******************************************
// Logic/Binary operations
// ******************************************

// Computes the bitwise AND-NOT of the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/68h7wd02(v=vs.100).aspx
inline __m128 _mm_andnot_ps(__m128 a , __m128 b ) 
{
	return (__m128)vbicq_s32((__m128i)b,(__m128i)a); // *NOTE* argument swap
}

// Computes the bitwise AND of the 128-bit value in b and the bitwise NOT of the 128-bit value in a. https://msdn.microsoft.com/en-us/library/vstudio/1beaceh8(v=vs.100).aspx
inline __m128i _mm_andnot_si128 (__m128i a, __m128i b) 
{
	return (__m128i)vbicq_s32(b,a); // *NOTE* argument swap
}

// Computes the bitwise AND of the 128-bit value in a and the 128-bit value in b. https://msdn.microsoft.com/en-us/library/vstudio/6d1txsa8(v=vs.100).aspx
inline __m128i _mm_and_si128 (__m128i a, __m128i b)	
{
	return (__m128i)vandq_s32(a,b);
}

// Computes the bitwise AND of the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/73ck1xc5(v=vs.100).aspx
inline __m128 _mm_and_ps(__m128 a , __m128 b ) 
{
	return (__m128)vandq_s32((__m128i)a,(__m128i)b);
}

// Computes the bitwise OR of the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/7ctdsyy0(v=vs.100).aspx
inline __m128 _mm_or_ps(__m128 a , __m128 b ) 
{
	return (__m128)vorrq_s32((__m128i)a,(__m128i)b);
}

//Computes the bitwise OR of the 128-bit value in a and the 128-bit value in b. https://msdn.microsoft.com/en-us/library/vstudio/ew8ty0db(v=vs.100).aspx
inline __m128i _mm_or_si128 (__m128i a, __m128i b) 
{
	return (__m128i)vorrq_s32(a,b);
}

// NEON does not provide this method
 // Creates a 4-bit mask from the most significant bits of the four single-precision, floating-point values. https://msdn.microsoft.com/en-us/library/vstudio/4490ys29(v=vs.100).aspx
inline int _mm_movemask_ps( __m128 a )
{
#if 0 // I am not yet convinced that the NEON version is faster than the C version of this
	uint32x4_t &ia = *(uint32x4_t *)&a;
	return (ia[0]>>31) | ((ia[1]>>30)&2) | ((ia[2]>>29)&4) | ((ia[3]>>28)&8);
#else
	static const uint32x4_t movemask = { 1, 2, 4, 8 };
	static const uint32x4_t highbit = { 0x80000000, 0x80000000, 0x80000000, 0x80000000 };
	uint32x4_t t0 = vreinterpretq_u32_f32(a);
	uint32x4_t t1 = vtstq_u32(t0, highbit);
	uint32x4_t t2 = vandq_u32(t1, movemask);
	uint32x2_t t3 = vorr_u32(vget_low_u32(t2), vget_high_u32(t2));
	return vget_lane_u32(t3, 0) | vget_lane_u32(t3, 1);
#endif
}

// NEON does not support a general purpose permute intrinsic
// Currently I am not sure whether the C implementation is faster or slower than the NEON version.
// Note, this has to be expanded as a template because the shuffle value must be an immediate value.
// The same is true on SSE as well.
// Selects four specific single-precision, floating-point values from a and b, based on the mask i. https://msdn.microsoft.com/en-us/library/vstudio/5f0858x0(v=vs.100).aspx
template <int i >
inline __m128 _mm_shuffle_ps_function(__m128 a , __m128 b)
{
#if 0 // I am not convinced that the NEON version is faster than the C version yet.
	__m128 ret;
	ret[0] = a[i&0x3];
	ret[1] = a[(i>>2)&0x3];
	ret[2] = b[(i>>4)&0x03];
	ret[3] = b[(i>>6)&0x03];
	return ret;
#else
	__m128 ret = vmovq_n_f32(vgetq_lane_f32(a, i&0x3));
	ret = vsetq_lane_f32(vgetq_lane_f32(a, (i>>2)&0x3), ret, 1);
	ret = vsetq_lane_f32(vgetq_lane_f32(b, (i>>4)&0x3), ret, 2);
	ret = vsetq_lane_f32(vgetq_lane_f32(b, (i>>6)&0x3), ret, 3);
	return ret;
#endif
}

#define _mm_shuffle_ps(a,b,i) _mm_shuffle_ps_function<i>(a,b)

// Shifts the 4 signed or unsigned 32-bit integers in a left by count bits while shifting in zeros. : https://msdn.microsoft.com/en-us/library/z2k3bbtb%28v=vs.90%29.aspx
#define _mm_slli_epi32(a,b) (__m128i)vshlq_n_s32(a,b)

// NEON does not provide a version of this function, here is an article about some ways to repro the results.
// http://stackoverflow.com/questions/11870910/sse-mm-movemask-epi8-equivalent-method-for-arm-neon
// Creates a 16-bit mask from the most significant bits of the 16 signed or unsigned 8-bit integers in a and zero extends the upper bits. https://msdn.microsoft.com/en-us/library/vstudio/s090c8fk(v=vs.100).aspx
inline int _mm_movemask_epi8 (__m128i _a)
{
	uint8x16_t input = (uint8x16_t)_a;
	const int8_t __attribute__ ((aligned (16))) xr[8] = {-7,-6,-5,-4,-3,-2,-1,0};
	uint8x8_t mask_and = vdup_n_u8(0x80);
	int8x8_t mask_shift = vld1_s8(xr);

	uint8x8_t lo = vget_low_u8(input);
	uint8x8_t hi = vget_high_u8(input);

	lo = vand_u8(lo, mask_and);
	lo = vshl_u8(lo, mask_shift);

	hi = vand_u8(hi, mask_and);
	hi = vshl_u8(hi, mask_shift);

	lo = vpadd_u8(lo,lo);
	lo = vpadd_u8(lo,lo);
	lo = vpadd_u8(lo,lo);

	hi = vpadd_u8(hi,hi);
	hi = vpadd_u8(hi,hi);
	hi = vpadd_u8(hi,hi);

	return ((hi[0] << 8) | (lo[0] & 0xFF));
}


// ******************************************
// Math operations
// ******************************************

 // Subtracts the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/1zad2k61(v=vs.100).aspx
inline __m128 _mm_sub_ps(__m128 a , __m128 b )
{
	return vsubq_f32(a,b);
}

// Subtracts the 4 signed or unsigned 32-bit integers of b from the 4 signed or unsigned 32-bit integers of a. https://msdn.microsoft.com/en-us/library/vstudio/fhh866h0(v=vs.100).aspx
inline __m128i _mm_sub_epi32 (__m128i a, __m128i b)
{
	return vsubq_s32(a,b);
}

// Adds the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/c9848chc(v=vs.100).aspx
inline __m128 _mm_add_ps(__m128 a , __m128 b ) 
{
	return vaddq_f32(a,b);
}

 // Adds the 4 signed or unsigned 32-bit integers in a to the 4 signed or unsigned 32-bit integers in b. https://msdn.microsoft.com/en-us/library/vstudio/09xs4fkk(v=vs.100).aspx
inline __m128i _mm_add_epi32 (__m128i a, __m128i b)
{
	return vaddq_s32(a,b);
}

// Multiplies the 8 signed or unsigned 16-bit integers from a by the 8 signed or unsigned 16-bit integers from b. https://msdn.microsoft.com/en-us/library/vstudio/9ks1472s(v=vs.100).aspx
inline __m128i _mm_mullo_epi16 (__m128i a, __m128i b)
{
	return (__m128i)vmulq_s16((int16x8_t)a,(int16x8_t)b);
}

// Multiplies the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/22kbk6t9(v=vs.100).aspx
inline __m128 _mm_mul_ps(__m128 a , __m128 b )
{
	return vmulq_f32(a,b);
}

// This version does additional iterations to improve accuracy.  Between 1 and 4 recommended.
// Computes the approximations of reciprocals of the four single-precision, floating-point values of a. https://msdn.microsoft.com/en-us/library/vstudio/796k1tty(v=vs.100).aspx
inline __m128 recipq_newton(__m128 in,int n)
{
	__m128 recip = vrecpeq_f32(in);
	for(int i=0; i<n; ++i)
	{
		recip = vmulq_f32(recip, vrecpsq_f32(recip, in));
	}
	return recip;
}

// Computes the approximations of reciprocals of the four single-precision, floating-point values of a. https://msdn.microsoft.com/en-us/library/vstudio/796k1tty(v=vs.100).aspx
inline __m128 _mm_rcp_ps(__m128 in)
{
	__m128 recip = vrecpeq_f32(in);
	recip = vmulq_f32(recip, vrecpsq_f32(recip, in));
	return recip;
}



// Computes the maximums of the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/ff5d607a(v=vs.100).aspx
inline __m128 _mm_max_ps(__m128 a , __m128 b ) 
{
	return vmaxq_f32(a,b);
}

// Computes the minima of the four single-precision, floating-point values of a and b. https://msdn.microsoft.com/en-us/library/vstudio/wh13kadz(v=vs.100).aspx
inline __m128 _mm_min_ps(__m128 a , __m128 b ) 
{
	return vminq_f32(a,b);
}

// Computes the pairwise minima of the 8 signed 16-bit integers from a and the 8 signed 16-bit integers from b. https://msdn.microsoft.com/en-us/library/vstudio/6te997ew(v=vs.100).aspx
inline __m128i _mm_min_epi16 (__m128i a, __m128i b) 
{
	return (__m128i)vminq_s16((int16x8_t)a,(int16x8_t)b);
}

 // Multiplies the 8 signed 16-bit integers from a by the 8 signed 16-bit integers from b. https://msdn.microsoft.com/en-us/library/vstudio/59hddw1d(v=vs.100).aspx
inline __m128i _mm_mulhi_epi16 (__m128i a, __m128i b)
{
	int16x8_t ret = vqdmulhq_s16((int16x8_t)a,(int16x8_t)b);
	ret = vshrq_n_s16(ret,1);
	return (__m128i)ret;
}

// ******************************************
// Compare operations
// ******************************************

// Compares for less than https://msdn.microsoft.com/en-us/library/vstudio/f330yhc8(v=vs.100).aspx
inline __m128 _mm_cmplt_ps(__m128 a, __m128 b ) 
{
	return (__m128)vcltq_f32(a,b);
}

// Compares for greater than. https://msdn.microsoft.com/en-us/library/vstudio/11dy102s(v=vs.100).aspx
inline __m128 _mm_cmpgt_ps(__m128 a, __m128 b ) 
{
	return (__m128)vcgtq_f32(a,b);
}

// Compares for greater than or equal. https://msdn.microsoft.com/en-us/library/vstudio/fs813y2t(v=vs.100).aspx
inline __m128 _mm_cmpge_ps(__m128 a, __m128 b ) 
{
	return (__m128)vcgeq_f32(a,b);
}

// Compares for less than or equal. https://msdn.microsoft.com/en-us/library/vstudio/1s75w83z(v=vs.100).aspx
inline __m128 _mm_cmple_ps(__m128 a , __m128 b ) 
{
	return (__m128)vcleq_f32(a,b);
}

// Compares for equality. https://msdn.microsoft.com/en-us/library/vstudio/36aectz5(v=vs.100).aspx
inline __m128 _mm_cmpeq_ps(__m128 a , __m128 b ) 
{
	return (__m128)vceqq_f32(a,b);
}

// Compares the 4 signed 32-bit integers in a and the 4 signed 32-bit integers in b for less than. https://msdn.microsoft.com/en-us/library/vstudio/4ak0bf5d(v=vs.100).aspx
inline __m128i _mm_cmplt_epi32 (__m128i a, __m128i b) 
{
	return (__m128i)vcltq_s32(a,b);
}

// Compares the 4 signed 32-bit integers in a and the 4 signed 32-bit integers in b for greater than. https://msdn.microsoft.com/en-us/library/vstudio/1s9f2z0y(v=vs.100).aspx
inline __m128i _mm_cmpgt_epi32 (__m128i a, __m128i b) 
{
	return (__m128i)vcgtq_s32(a,b);
}

// ******************************************
// Conversions
// ******************************************

// Converts the four single-precision, floating-point values of a to signed 32-bit integer values using truncate. https://msdn.microsoft.com/en-us/library/vstudio/1h005y6x(v=vs.100).aspx
inline __m128i _mm_cvttps_epi32 (__m128 a) 
{
	return vcvtq_s32_f32(a);
}

// Converts the four signed 32-bit integer values of a to single-precision, floating-point values https://msdn.microsoft.com/en-us/library/vstudio/36bwxcx5(v=vs.100).aspx
inline __m128 _mm_cvtepi32_ps (__m128i a) 
{
	return vcvtq_f32_s32(a);
}

// Converts the four single-precision, floating-point values of a to signed 32-bit integer values. https://msdn.microsoft.com/en-us/library/vstudio/xdc42k5e(v=vs.100).aspx
inline __m128i _mm_cvtps_epi32 (__m128 a) 
{
#if __aarch64__
	return vcvtaq_s32_f32(a);
#else
	__m128 half = vdupq_n_f32(0.5f);
	const __m128 sign = vcvtq_f32_u32((vshrq_n_u32(vreinterpretq_u32_f32(a), 31)));
	const __m128 aPlusHalf = vaddq_f32(a, half);
	const __m128 aRound = vsubq_f32(aPlusHalf, sign);
	return vcvtq_s32_f32(aRound);
#endif
}


#endif