TI的定点DSP浮点数值表示转换函数

static double int2double(int nbit, int nfraction, int is_signal, unsigned int src)
{
unsigned int VAL_MASK = 0;
double rlt = 0;

if(is_signal)
{
VAL_MASK = (1<<(nbit-1))-1;
if((int)src >= (1<<(nbit-1)))
{
src = src&VAL_MASK;
src = ~src;
src = src&VAL_MASK;
src = src+1;
src = src&VAL_MASK;
rlt = src*(-1.0)/(1<<nfraction);
}
else
{
rlt = src*1.0/(1<<nfraction);
}
}
else
{
VAL_MASK = (1<<nbit)-1;
src = src&VAL_MASK;
rlt = src*1.0/(1<<nfraction);

}
return rlt;