ref: 8309f15c3669d684da7c3fe2b6748f9362e1cc38
dir: /sys/src/ape/lib/9/386/getfcr.s/
TEXT setfcr(SB), $0 MOVL p+0(FP),AX XORB $0x3f,AX PUSHW AX WAIT FLDCW 0(SP) POPW AX RET TEXT getfcr(SB), $0 PUSHW AX WAIT FSTCW 0(SP) POPW AX XORB $0x3f,AX RET TEXT getfsr(SB), $0 WAIT FSTSW AX RET TEXT setfsr(SB), $0 WAIT FCLEX RET