tf->tsc_lsb_truncate = vheader->tsc_lsb_truncate;
tf->tscbits = vheader->tscbits;
tf->tsc_msb_cutoff = 32 - tf->tsc_lsb_truncate - tf->tscbits;
tf->tsc_lsb_truncate = vheader->tsc_lsb_truncate;
tf->tscbits = vheader->tscbits;
tf->tsc_msb_cutoff = 32 - tf->tsc_lsb_truncate - tf->tscbits;