CODEWITHSUNDEEP
cmacros
A.nechi
A.nechi

Reputation: 541

Macro similar to SIMD instruction

I' trying to create some macros that are somehow similar to SIMD intrinsics. And the reason why I want to create these macros is that I'm working with a simulator called "Gem5" that does not support SIMD.

Well, first of all, i created a structure that defines a vector of 4 packed single precision floating point elements like so:

  typedef struct
  {
  float vec1;
  float vec2;
  float vec3;
  float vec4;
  } __m128 __attribute__((aligned(16)));

then I've created the ADD macro:

   #define __M128_MM_ADD_PS(dest, a,b)  \
  {                                    \
  (dest)->vec1 = (a)->vec1 + (b)->vec1; \
  (dest)->vec2 = (a)->vec2 + (b)->vec2; \
  (dest)->vec3 = (a)->vec3 + (b)->vec3; \
  (dest)->vec4 = (a)->vec4 + (b)->vec4; \
  }

and another macro for storing the results in a float array:

  #define __M128_MM_MOVA_PS(dest, a) \
  { \
  dest[0] = a->vec1; \
  dest[1] = a->vec2; \
  dest[2] = a->vec3; \
  dest[3] = a->vec4; \
  }

and to them I've declared the variables as __m128 and a float array to store the results, this way(a little example):

 void foo(){
 __m128 bfly0_rv, x_n2_vec, x_N2_vec;
 float *x;

 __M128_MM_ADD_PS(bfly0_rv,x_n2_vec,x_N2_vec);
 __M128_MM_MOVA_PS(&x[n2],bfly0_rv);
 }

and I'm getting these kind of error messages:

for the ADD macro error: invalid type argument of ‘->’ (have ‘__m128’) (dest)->vec4 = (a)->vec4 + (b)->vec4;

for the storing macro error: invalid type argument of ‘->’ (have ‘__m128’) dest[3] = a->vec4;

Anyone could have an idea about that?

Upvotes: 2

Views: 197

Answers (1)

Sergio
Sergio

Reputation: 8209

All of your macros will work with pointers to __m128, but you pass just __m128 not __m128 *. Just replace -> with . inside macros or prepend macro arguments with &:

__M128_MM_ADD_PS(&bfly0_rv, &x_n2_vec, &x_N2_vec);
__M128_MM_MOVA_PS(&x[n2], &bfly0_rv);

Also don't forget to enclose dest and a in braces in __M128_MM_MOVA_PS.

P.S. It would be better to use do { ... } while(0) instead of { ... } in macro definitions.

Upvotes: 4

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