ref: 0b6f19f98cfc9a62fc4df1661c63c77ffe459f67
dir: /sys/src/libc/amd64/getfcr.s/
TEXT setfcr(SB), $4 XORL $(0x3F<<7),RARG /* bits are cleared in csr to enable them */ ANDL $0xFFC0, RARG /* just the fcr bits */ WAIT /* is this needed? */ STMXCSR 0(SP) MOVL 0(SP), AX ANDL $~0x3F, AX ORL RARG, AX MOVL AX, 0(SP) LDMXCSR 0(SP) RET TEXT getfcr(SB), $4 WAIT STMXCSR 0(SP) MOVWLZX 0(SP), AX ANDL $0xFFC0, AX XORL $(0x3F<<7),AX RET TEXT getfsr(SB), $4 WAIT STMXCSR 0(SP) MOVL 0(SP), AX ANDL $0x3F, AX RET TEXT setfsr(SB), $4 ANDL $0x3F, RARG WAIT STMXCSR 0(SP) MOVL 0(SP), AX ANDL $~0x3F, AX ORL RARG, AX MOVL AX, 0(SP) LDMXCSR 0(SP) RET