ref: 87d72e7e8614d96b4f61adae5fb05b0534231c4c dir: /libkern/getfcr-thumb.s/
TEXT setfcr(SB), $0 RET TEXT getfcr(SB), $0 RET TEXT getfsr(SB), $0 RET TEXT setfsr(SB), $0 RET