STAMP_MASK
int so = STAMP_SHIFT(fr[index], nibble) & STAMP_MASK; \
int so = STAMP_SHIFT(fr[index], nibble) & STAMP_MASK; \
int so = STAMP_SHIFT(fr[index], nibble) & STAMP_MASK; \
int so = STAMP_SHIFT(fr[index], nibble) & STAMP_MASK; \