What is the equivalent of v4sf and __attribute__ in Visual Studio C++? - c++

Question

typedef float v4sf __attribute__ ((mode(V4SF)));
This is in GCC. Anyone knows the equivalence syntax?
VS 2010 will show __attribute__ has no storage class of this type, and mode is not defined.
I searched on the Internet and it said
Equivalent to __attribute__( aligned( size ) ) in GCC
It is helpful
for former unix developers or people writing code that works on
multiple platforms that in GCC you achieve the same results using
attribute( aligned( ... ) )
See here for more information:
http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Type-Attributes.html#Type-Attributes
The full GCC code is here: http://pastebin.com/bKkTTmH1

Answer 1

If you're looking for the alignment directive in VC++ it's __declspec(align(16)). (or whatever you want the alignment to be)
And example usage is this:
__declspec(align(16)) float x[] = {1.,2.,3.,4.};
http://msdn.microsoft.com/en-us/library/83ythb65.aspx
Note that both attribute (in GCC) and __declspec (in VC++) are compiler-specific extensions.
EDIT :
Now that I take a second look at the code, it's gonna take more work than just replacing the __attribute__ line with the VC++ equivalent to get it to compile in VC++.
VC++ doesn't have any if these macros/functions that you are using:
__builtin_ia32_xorps
__builtin_ia32_loadups
__builtin_ia32_mulps
__builtin_ia32_addps
__builtin_ia32_storeups
You're better off just replacing all of those with SSE intrinsics - which will work on both GCC and VC++.
Here's the code converted to intrinsics:
float *mv_mult(float mat[SIZE][SIZE], float vec[SIZE]) {
static float ret[SIZE];
float temp[4];
int i, j;
__m128 m, v, r;
for (i = 0; i < SIZE; i++) {
r = _mm_xor_ps(r, r);
for (j = 0; j < SIZE; j += 4) {
m = _mm_loadu_ps(&mat[i][j]);
v = _mm_loadu_ps(&vec[j]);
v = _mm_mul_ps(m, v);
r = _mm_add_ps(r, v);
}
_mm_storeu_ps(temp, r);
ret[i] = temp[0] + temp[1] + temp[2] + temp[3];
}
return ret;
}

Answer 2

V4SF and friends have to do with GCC "vector extensions":
http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Vector-Extensions.html#Vector%20Extensions
http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/X86-Built-in-Functions.html
I'm not sure how much - if any of this stuff - is supported in MSVS/MSVC. Here are a few links:
http://www.codeproject.com/KB/recipes/sseintro.aspx?msg=643444
http://msdn.microsoft.com/en-us/library/y0dh78ez%28v=vs.80%29.aspx
http://msdn.microsoft.com/en-us/library/01fth20w.aspx