ref: 1a55b8d1f0253b4d39b1972978b469a352f0f94b
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