ref: 4cd03abefe80c9d7ce97d7dfb488e7ed5a8163c8 dir: /sys/src/libc/arm/getfcr.s/
TEXT setfcr(SB), $0 RET TEXT getfcr(SB), $0 RET TEXT getfsr(SB), $0 RET TEXT setfsr(SB), $0 RET