A simplest assembly error - need help

[includeh10]

I test a little _asm code, it works if type = float but error if type = double.

type GetSum()
{
type pData[] = {1.1, 2.2, 3.3};
type dbReturn = 0;

//one line of c code, which will be replaced by _asm bellow
dbReturn = pData[0];

//------------------
return dbReturn;
}

asm for above one line

_asm
{
mov esi, pData
fld [esi]
fstp dbResult
}

the little asm is correct if

typedef float type;

but error if

typedef double type;

why the little asm works for float but error for double? please help. thanks.