Is there an intrinsic to store 3 float values?

Thanks for the answer, Simon.

It's rather unfortunate that it takes 4 instructions, but I suppose there's no other way.

Thanks for the answer, Simon.

It's rather unfortunate that it takes 4 instructions, but I suppose there's no other way.

A big part of writing effective DSP/NEON type code is getting the data flow right, so you don't need to move or copy data around. The actual store here is only a single cycle, provided it's possible to work the data motion into the algorithm so it isn't an extra step bolted on at the end of an existing assembler routine.

Well, I can't see how, although I am no expert in this. You're welcome to try if you want.

This is the code that I have so far:

[code]

   float32x4_t matrixRow1 = vld1q_f32(m);

   float32x4_t matrixRow2 = vld1q_f32(&m[4]);

    float32x4_t matrixRow3 = vld1q_f32(&m[8]);

    float32x4_t matrixRow4 = vld1q_f32(&m[12]);

    float32x4_t out1 = vmulq_n_f32(matrixRow1, pInVertex[0]); //    out1 = matrixRow1 * pInVertex1[0];

    out1 = vmlaq_n_f32(out1, matrixRow2, pInVertex[1]); //    out1 += matrixRow2 * pInVertex1[1];

    out1 = vmlaq_n_f32(out1, matrixRow3, pInVertex[2]); //    out1 += matrixRow3 * pInVertex1[2];

    float values[4];

    vst1q_f32(values, out1);

    // then add 3 of values[4] to pOutVertex1

     // note: I gave up and used c++ here.

    pOutVertex[0] += values[0];

    pOutVertex[1] += values[1];

    pOutVertex[2] += values[2];

#else

    pOutVertex[0] += weight*(pInVertex[0]*m[0] + pInVertex[1]*m[4] + pInVertex[2]*m[8] + m[12]);

    pOutVertex[1] += weight*(pInVertex[0]*m[1] + pInVertex[1]*m[5] + pInVertex[2]*m[9] + m[13]);

    pOutVertex[2] += weight*(pInVertex[0]*m[2] + pInVertex[1]*m[6] + pInVertex[2]*m[10] + m[14]);

#endif

}

[/code]

Things which are not a power of two or a full register are a pain in NEON, but if you are willing to sacrifice a little storage space the obvious data layout change would be to allocate vec4() inputs and outputs. The final increment then becomes a vec4 load of pOutVertex, a vec4 addition, and a vec4 store to write the incremented value of pOutVertex.