i386/i386.reference/SMSW.htm

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   4 <TITLE>80386 Programmer's Reference Manual -- Opcode SMSW</TITLE>
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   7 <B>up:</B> <A HREF="c17.htm">
   8 Chapter 17 -- 80386 Instruction Set</A><BR>
   9 <B>prev:</B><A HREF="SLDT.htm"> SLDT Store Local Descriptor Table Register</A><BR>
  10 <B>next:</B><A HREF="STC.htm"> STC Set Carry Flag</A>
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  13 <P>
  14 <H1>SMSW -- Store Machine Status Word</H1>
  15
  16 <PRE>
  17 Opcode      Instruction     Clocks          Description
  18
  19 0F  01 /4   SMSW r/m16      2/3,pm=2/2      Store machine status word to EA
  20                                             word
  21 </PRE>
  22
  23
  24 <H2>Operation</H2>
  25
  26 <PRE>
  27 r/m16 := MSW;
  28 </PRE>
  29
  30 <H2>Description</H2>
  31
  32 SMSW stores the machine status word (part of CR0) in the two-byte register
  33 or memory location indicated by the effective address operand.
  34
  35 <H2>Flags Affected</H2>
  36
  37 None
  38
  39 <H2>Protected Mode Exceptions</H2>
  40
  41 #GP(0) if the result is in a nonwritable segment; #GP(0) for an illegal
  42 memory operand effective address in the CS, DS, ES, FS, or GS segments;
  43 #SS(0) for an illegal address in the SS segment; #PF(fault-code) for a page
  44 fault
  45
  46 <H2>Real Address Mode Exceptions</H2>
  47
  48 Interrupt 13 if any part of the operand would lie outside of the effective
  49 address space from 0 to 0FFFFH
  50
  51 <H2>Virtual 8086 Mode Exceptions</H2>
  52
  53 Same exceptions as in Real Address Mode; #PF(fault-code) for a page fault
  54
  55 <H2>Notes</H2>
  56
  57 This instruction is provided for compatibility with the 80286; 80386
  58 programs should use <A HREF="MOVRS.htm">MOV</A> ..., CR0.
  59 <P>
  60 <HR>
  61 <P>
  62 <B>up:</B> <A HREF="c17.htm">
  63 Chapter 17 -- 80386 Instruction Set</A><BR>
  64 <B>prev:</B><A HREF="SLDT.htm"> SLDT Store Local Descriptor Table Register</A><BR>
  65 <B>next:</B><A HREF="STC.htm"> STC Set Carry Flag</A>
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