hw/i386.reference/MOVSX.htm

   1 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
   2 <HTML>
   3 <HEAD>
   4 <TITLE>80386 Programmer's Reference Manual -- Opcode MOVSX</TITLE>
   5 </HEAD>
   6 <BODY>
   7 <B>up:</B> <A HREF="c17.htm">
   8 Chapter 17 -- 80386 Instruction Set</A><BR>
   9 <B>prev:</B><A HREF="MOVS.htm">
  10 MOVS/MOVSB/MOVSW/MOVSD Move Data from String to String</A><BR>
  11 <B>next:</B><A HREF="MOVZX.htm"> MOVZX Move with Zero-Extend</A>
  12 <P>
  13 <HR>
  14 <P>
  15 <H1>MOVSX -- Move with Sign-Extend</H1>
  16
  17 <PRE>
  18 Opcode     Instruction        Clocks   Description
  19
  20 0F  BE /r  MOVSX r16,r/m8     3/6      Move byte to word with sign-extend
  21 0F  BE /r  MOVSX r32,r/m8     3/6      Move byte to dword, sign-extend
  22 0F  BF /r  MOVSX r32,r/m16    3/6      Move word to dword, sign-extend
  23 </PRE>
  24
  25 <H2>Operation</H2>
  26
  27 <PRE>
  28 DEST := SignExtend(SRC);
  29 </PRE>
  30
  31 <H2>Description</H2>
  32
  33 MOVSX reads the contents of the effective address or register as a byte
  34 or a word, sign-extends the value to the operand-size attribute of the
  35 instruction (16 or 32 bits), and stores the result in the destination
  36 register.
  37
  38 <H2>Flags Affected</H2>
  39
  40 None
  41
  42 <H2>Protected Mode Exceptions</H2>
  43
  44 #GP(0) for an illegal memory operand effective address in the CS, DS,
  45 ES, FS or GS segments; #SS(0) for an illegal address in the SS segment;
  46 #PF(fault-code) for a page fault
  47
  48 <H2>Real Address Mode Exceptions</H2>
  49
  50 Interrupt 13 if any part of the operand would lie outside of the effective
  51 address space from 0 to 0FFFFH
  52
  53 <H2>Virtual 8086 Mode Exceptions</H2>
  54
  55 Same exceptions as in Real Address Mode; #PF(fault-code) for a page
  56 fault
  57
  58
  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="MOVS.htm">
  65 MOVS/MOVSB/MOVSW/MOVSD Move Data from String to String</A><BR>
  66 <B>next:</B><A HREF="MOVZX.htm"> MOVZX Move with Zero-Extend</A>
  67 </BODY>