
/* Copyright (c) 2013  Julien Pommier ( pommier@modartt.com )

   Redistribution and use of the Software in source and binary forms,
   with or without modification, is permitted provided that the
   following conditions are met:

   - Neither the names of NCAR's Computational and Information Systems
   Laboratory, the University Corporation for Atmospheric Research,
   nor the names of its sponsors or contributors may be used to
   endorse or promote products derived from this Software without
   specific prior written permission.  

   - Redistributions of source code must retain the above copyright
   notices, this list of conditions, and the disclaimer below.

   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions, and the disclaimer below in the
   documentation and/or other materials provided with the
   distribution.

   THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT
   HOLDERS BE LIABLE FOR ANY CLAIM, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
   SOFTWARE.
*/

#pragma once

#include <assert.h>
#include <string.h>
#include <stdint.h>


/*
 *  SIMD reference material:
 * 
 * general SIMD introduction:
 * https://www.linuxjournal.com/content/introduction-gcc-compiler-intrinsics-vector-processing
 * 
 * SSE 1:
 * https://software.intel.com/sites/landingpage/IntrinsicsGuide/
 * 
 * ARM NEON:
 * https://developer.arm.com/architectures/instruction-sets/simd-isas/neon/intrinsics
 * 
 * Altivec:
 * https://www.nxp.com/docs/en/reference-manual/ALTIVECPIM.pdf
 * https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/PowerPC-AltiVec_002fVSX-Built-in-Functions.html
 * better one?
 * 
 */


/*
   Altivec support macros 
*/
#if !defined(PFFFT_SIMD_DISABLE) && (defined(__ppc__) || defined(__ppc64__))
#include <altivec.h>
typedef vector float v4sf;
#  define SIMD_SZ 4
#  define VREQUIRES_ALIGN 1  /* not sure, if really required */
#  define VZERO() ((vector float) vec_splat_u8(0))
#  define VMUL(a,b) vec_madd(a,b, VZERO())
#  define VADD(a,b) vec_add(a,b)
#  define VMADD(a,b,c) vec_madd(a,b,c)
#  define VSUB(a,b) vec_sub(a,b)
inline v4sf ld_ps1(const float *p) { v4sf v=vec_lde(0,p); return vec_splat(vec_perm(v, v, vec_lvsl(0, p)), 0); }
#  define LD_PS1(p) ld_ps1(&p)
#  define INTERLEAVE2(in1, in2, out1, out2) { v4sf tmp__ = vec_mergeh(in1, in2); out2 = vec_mergel(in1, in2); out1 = tmp__; }
#  define UNINTERLEAVE2(in1, in2, out1, out2) {                           \
    vector unsigned char vperm1 =  (vector unsigned char)(0,1,2,3,8,9,10,11,16,17,18,19,24,25,26,27); \
    vector unsigned char vperm2 =  (vector unsigned char)(4,5,6,7,12,13,14,15,20,21,22,23,28,29,30,31); \
    v4sf tmp__ = vec_perm(in1, in2, vperm1); out2 = vec_perm(in1, in2, vperm2); out1 = tmp__; \
  }
#  define VTRANSPOSE4(x0,x1,x2,x3) {              \
    v4sf y0 = vec_mergeh(x0, x2);               \
    v4sf y1 = vec_mergel(x0, x2);               \
    v4sf y2 = vec_mergeh(x1, x3);               \
    v4sf y3 = vec_mergel(x1, x3);               \
    x0 = vec_mergeh(y0, y2);                    \
    x1 = vec_mergel(y0, y2);                    \
    x2 = vec_mergeh(y1, y3);                    \
    x3 = vec_mergel(y1, y3);                    \
  }
#  define VSWAPHL(a,b) vec_perm(a,b, (vector unsigned char)(16,17,18,19,20,21,22,23,8,9,10,11,12,13,14,15))
#  define VALIGNED(ptr) ((((uintptr_t)(ptr)) & 0xF) == 0)

/*
  SSE1 support macros
*/
#elif !defined(PFFFT_SIMD_DISABLE) && (defined(__x86_64__) || defined(_M_X64) || defined(i386) || defined(__i386__) || defined(_M_IX86))

#include <xmmintrin.h>
typedef __m128 v4sf;
/* 4 floats by simd vector -- this is pretty much hardcoded in the preprocess/finalize functions
 *  anyway so you will have to work if you want to enable AVX with its 256-bit vectors. */
#  define SIMD_SZ 4
#  define VREQUIRES_ALIGN 1
#  define VZERO() _mm_setzero_ps()
#  define VMUL(a,b) _mm_mul_ps(a,b)
#  define VADD(a,b) _mm_add_ps(a,b)
#  define VMADD(a,b,c) _mm_add_ps(_mm_mul_ps(a,b), c)
#  define VSUB(a,b) _mm_sub_ps(a,b)
#  define LD_PS1(p) _mm_set1_ps(p)
#  define VLOAD_UNALIGNED(ptr)  _mm_loadu_ps(ptr)
#  define VLOAD_ALIGNED(ptr)    _mm_load_ps(ptr)
#  define INTERLEAVE2(in1, in2, out1, out2) { v4sf tmp__ = _mm_unpacklo_ps(in1, in2); out2 = _mm_unpackhi_ps(in1, in2); out1 = tmp__; }
#  define UNINTERLEAVE2(in1, in2, out1, out2) { v4sf tmp__ = _mm_shuffle_ps(in1, in2, _MM_SHUFFLE(2,0,2,0)); out2 = _mm_shuffle_ps(in1, in2, _MM_SHUFFLE(3,1,3,1)); out1 = tmp__; }
#  define VTRANSPOSE4(x0,x1,x2,x3) _MM_TRANSPOSE4_PS(x0,x1,x2,x3)
#  define VSWAPHL(a,b) _mm_shuffle_ps(b, a, _MM_SHUFFLE(3,2,1,0))
/* reverse/flip all floats */
#  define VREV_S(a)    _mm_shuffle_ps(a, a, _MM_SHUFFLE(0,1,2,3))
/* reverse/flip complex floats */
#  define VREV_C(a)    _mm_shuffle_ps(a, a, _MM_SHUFFLE(1,0,3,2))
#  define VALIGNED(ptr) ((((uintptr_t)(ptr)) & 0xF) == 0)

/*
  ARM NEON support macros
*/
#elif !defined(PFFFT_SIMD_DISABLE) && (defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64))
#  include <arm_neon.h>
typedef float32x4_t v4sf;
#  define SIMD_SZ 4
#  define VREQUIRES_ALIGN 0  /* usually no alignment required */
#  define VZERO() vdupq_n_f32(0)
#  define VMUL(a,b) vmulq_f32(a,b)
#  define VADD(a,b) vaddq_f32(a,b)
#  define VMADD(a,b,c) vmlaq_f32(c,a,b)
#  define VSUB(a,b) vsubq_f32(a,b)
#  define LD_PS1(p) vld1q_dup_f32(&(p))
#  define VLOAD_UNALIGNED(ptr)  (*(ptr))
#  define VLOAD_ALIGNED(ptr)    (*(ptr))
#  define INTERLEAVE2(in1, in2, out1, out2) { float32x4x2_t tmp__ = vzipq_f32(in1,in2); out1=tmp__.val[0]; out2=tmp__.val[1]; }
#  define UNINTERLEAVE2(in1, in2, out1, out2) { float32x4x2_t tmp__ = vuzpq_f32(in1,in2); out1=tmp__.val[0]; out2=tmp__.val[1]; }
#  define VTRANSPOSE4(x0,x1,x2,x3) {                                    \
    float32x4x2_t t0_ = vzipq_f32(x0, x2);                              \
    float32x4x2_t t1_ = vzipq_f32(x1, x3);                              \
    float32x4x2_t u0_ = vzipq_f32(t0_.val[0], t1_.val[0]);              \
    float32x4x2_t u1_ = vzipq_f32(t0_.val[1], t1_.val[1]);              \
    x0 = u0_.val[0]; x1 = u0_.val[1]; x2 = u1_.val[0]; x3 = u1_.val[1]; \
  }
// marginally faster version
//#  define VTRANSPOSE4(x0,x1,x2,x3) { asm("vtrn.32 %q0, %q1;\n vtrn.32 %q2,%q3\n vswp %f0,%e2\n vswp %f1,%e3" : "+w"(x0), "+w"(x1), "+w"(x2), "+w"(x3)::); }
#  define VSWAPHL(a,b) vcombine_f32(vget_low_f32(b), vget_high_f32(a))
#  define VALIGNED(ptr) ((((uintptr_t)(ptr)) & 0x3) == 0)
#else
#  if !defined(PFFFT_SIMD_DISABLE)
#    warning "building with simd disabled !\n";
#    define PFFFT_SIMD_DISABLE // fallback to scalar code
#  endif
#endif

// fallback mode for situations where SSE/Altivec are not available, use scalar mode instead
#ifdef PFFFT_SIMD_DISABLE
typedef float v4sf;
#  define SIMD_SZ 1
#  define VREQUIRES_ALIGN 0
#  define VZERO() 0.f
#  define VMUL(a,b) ((a)*(b))
#  define VADD(a,b) ((a)+(b))
#  define VMADD(a,b,c) ((a)*(b)+(c))
#  define VSUB(a,b) ((a)-(b))
#  define LD_PS1(p) (p)
#  define VLOAD_UNALIGNED(ptr)  (*(ptr))
#  define VLOAD_ALIGNED(ptr)    (*(ptr))
#  define VALIGNED(ptr) ((((uintptr_t)(ptr)) & 0x3) == 0)
#endif

// shortcuts for complex multiplcations
#define VCPLXMUL(ar,ai,br,bi) { v4sf tmp; tmp=VMUL(ar,bi); ar=VMUL(ar,br); ar=VSUB(ar,VMUL(ai,bi)); ai=VMUL(ai,br); ai=VADD(ai,tmp); }
#define VCPLXMULCONJ(ar,ai,br,bi) { v4sf tmp; tmp=VMUL(ar,bi); ar=VMUL(ar,br); ar=VADD(ar,VMUL(ai,bi)); ai=VMUL(ai,br); ai=VSUB(ai,tmp); }
#ifndef SVMUL
// multiply a scalar with a vector
#define SVMUL(f,v) VMUL(LD_PS1(f),v)
#endif

typedef union v4sf_union {
  v4sf  v;
  float f[SIMD_SZ];
} v4sf_union;

#if !defined(PFFFT_SIMD_DISABLE)

#define assertv4(v,f0,f1,f2,f3) assert(v.f[0] == (f0) && v.f[1] == (f1) && v.f[2] == (f2) && v.f[3] == (f3))

/* detect bugs with the vector support macros */
static void Vvalidate_simd() {
  float f[16] = { 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 };
  v4sf_union a0, a1, a2, a3, t, u; 
  memcpy(a0.f, f, 4*sizeof(float));
  memcpy(a1.f, f+4, 4*sizeof(float));
  memcpy(a2.f, f+8, 4*sizeof(float));
  memcpy(a3.f, f+12, 4*sizeof(float));

  t = a0; u = a1; t.v = VZERO();
  printf("VZERO=[%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3]); assertv4(t, 0, 0, 0, 0);
  t.v = VADD(a1.v, a2.v);
  printf("VADD(4:7,8:11)=[%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3]); assertv4(t, 12, 14, 16, 18);
  t.v = VMUL(a1.v, a2.v);
  printf("VMUL(4:7,8:11)=[%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3]); assertv4(t, 32, 45, 60, 77);
  t.v = VMADD(a1.v, a2.v,a0.v);
  printf("VMADD(4:7,8:11,0:3)=[%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3]); assertv4(t, 32, 46, 62, 80);

  INTERLEAVE2(a1.v,a2.v,t.v,u.v);
  printf("INTERLEAVE2(4:7,8:11)=[%2g %2g %2g %2g] [%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3], u.f[0], u.f[1], u.f[2], u.f[3]);
  assertv4(t, 4, 8, 5, 9); assertv4(u, 6, 10, 7, 11);
  UNINTERLEAVE2(a1.v,a2.v,t.v,u.v);
  printf("UNINTERLEAVE2(4:7,8:11)=[%2g %2g %2g %2g] [%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3], u.f[0], u.f[1], u.f[2], u.f[3]);
  assertv4(t, 4, 6, 8, 10); assertv4(u, 5, 7, 9, 11);

  t.v=LD_PS1(f[15]);
  printf("LD_PS1(15)=[%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3]);
  assertv4(t, 15, 15, 15, 15);
  t.v = VSWAPHL(a1.v, a2.v);
  printf("VSWAPHL(4:7,8:11)=[%2g %2g %2g %2g]\n", t.f[0], t.f[1], t.f[2], t.f[3]);
  assertv4(t, 8, 9, 6, 7);
  VTRANSPOSE4(a0.v, a1.v, a2.v, a3.v);
  printf("VTRANSPOSE4(0:3,4:7,8:11,12:15)=[%2g %2g %2g %2g] [%2g %2g %2g %2g] [%2g %2g %2g %2g] [%2g %2g %2g %2g]\n", 
         a0.f[0], a0.f[1], a0.f[2], a0.f[3], a1.f[0], a1.f[1], a1.f[2], a1.f[3], 
         a2.f[0], a2.f[1], a2.f[2], a2.f[3], a3.f[0], a3.f[1], a3.f[2], a3.f[3]); 
  assertv4(a0, 0, 4, 8, 12); assertv4(a1, 1, 5, 9, 13); assertv4(a2, 2, 6, 10, 14); assertv4(a3, 3, 7, 11, 15);
}
#endif //!PFFFT_SIMD_DISABLE

/* SSE and co like 16-bytes aligned pointers */
#define MALLOC_V4SF_ALIGNMENT 64 // with a 64-byte alignment, we are even aligned on L2 cache lines...

static
void *Valigned_malloc(size_t nb_bytes) {
  void *p, *p0 = malloc(nb_bytes + MALLOC_V4SF_ALIGNMENT);
  if (!p0) return (void *) 0;
  p = (void *) (((size_t) p0 + MALLOC_V4SF_ALIGNMENT) & (~((size_t) (MALLOC_V4SF_ALIGNMENT-1))));
  *((void **) p - 1) = p0;
  return p;
}

static
void Valigned_free(void *p) {
  if (p) free(*((void **) p - 1));
}
