_fpxreg
struct _fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */
struct _fpxreg *st;
struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0];
struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0];
struct _fpxreg *st = NULL;
st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);