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Detect AVX presence using algorithm specified in the Intel' SDM Volume 1 section 14.3 "DETECTION OF AVX INSTRUCTIONS". #3

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Detect AVX presence using algorithm specified in the Intel' SDM Volume 1 section 14.3 "DETECTION OF AVX INSTRUCTIONS". #3

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20 changes: 19 additions & 1 deletion pycpuid/_pycpuid.c
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Original file line number Diff line number Diff line change
Expand Up @@ -47,11 +47,29 @@ static PyObject* _pycpuid_cpuid(PyObject* module, PyObject* args)
return Py_BuildValue("IIII", cpuinfo[0], cpuinfo[1], cpuinfo[2], cpuinfo[3]);
}


static PyObject* _pycpuid_xgetbv(PyObject* module, PyObject* args)
{
unsigned regs[2] = { 0, 0 };
unsigned ecx;
if (!PyArg_ParseTuple(args, "I:ecx", &ecx))
{
return 0;
}
#ifdef _MSC_VER
regs[0] = regs[1] = 0; /* XXX */
#else
__asm__ __volatile__(
"xgetbv"
: "=a"(regs[0]), "=d"(regs[1])
: "c"(ecx));
#endif
return Py_BuildValue("II", regs[0], regs[1]);
}

static PyMethodDef _pycpuid_methods[] =
{
{ "cpuid", _pycpuid_cpuid, METH_VARARGS, "cpuid(eax) -> (eax, ebx, ecx, edx)"},
{ "xgetbv", _pycpuid_xgetbv, METH_VARARGS, "xgetbv(ecx) -> (eax, edx)"},
{ 0, 0, 0, 0 },
};

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19 changes: 17 additions & 2 deletions pycpuid/pycpuid.py
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Original file line number Diff line number Diff line change
Expand Up @@ -11,13 +11,24 @@

EXTENDED_OFFSET = 0x80000000


def cpuid(infotype):
'''
cpuid(infotype) -> (eax, ebx, ecx, edx)
'''
return _pycpuid.cpuid(infotype)

def xgetbv(reg):
'''
'''
info = cpuid(1)
if (info[2] & (1 << 27)) != 0:
return _pycpuid.xgetbv(reg)
return 0

def xcr0():
'''
'''
return xgetbv(0)

def vendor():
a, b, c, d = cpuid(0)
Expand Down Expand Up @@ -63,7 +74,11 @@ def features():
returns sequence of available features
'''
info = cpuid(1)
return [key for key, reg, bit in _feat_table if info[reg] & (1 << bit)]
res = [key for key, reg, bit in _feat_table if info[reg] & (1 << bit)]
rxcr0 = xcr0()
if (rxcr0[0] & 0x5) == 0x5 and (info[2] & (1 << 28)) != 0:
res.append("AVX")
return res

_feat_table = [
("FPU", 3, 0),
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