SMSW -- Store Machine Status Word

SMSW -- Store Machine Status Word Opcode Instruction Clocks Description 0F 01 /4 SMSW r/m16 2/3,pm=2/2 Store machine status word to EA word Operation r/m16 = MSW; Description SMSW stores the machine status word (part of CR0) in the two-byte register or memory location indicated by the effective address operand. Flags Affected None Protected Mode Exceptions #GP(0) if the result is in a nonwritable segment; #GP(0) for an illegal memory operand effective address in the CS, DS, ES, FS, or GS segments; #SS(0) for an illegal address in the SS segment; #PF(fault-code) for a page fault Real Address Mode Exceptions Interrupt 13 if any part of the operand would lie outside of the effective address space from 0 to 0FFFFH Virtual 8086 Mode Exceptions Same exceptions as in Real Address Mode; #PF(fault-code) for a page fault Notes This instruction is provided for compatibility with the 80286; 80386 programs should use MOV ..., CR0.