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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><HTML><HEAD><TITLE>80386 Programmer's Reference Manual -- Section 14.2</TITLE></HEAD><BODY><B>up:</B> <A HREF="c14.htm">Chapter 14 -- 80386 Real-Address Mode</A><BR><B>prev:</B> <A HREF="s14_01.htm">14.1 Physical Address Formation</A><BR><B>next:</B> <A HREF="s14_03.htm">14.3 Interrupt and Exception Handling</A><P><HR><P><H1>14.2 Registers and Instructions</H1>The register set available in real-address mode includes all the registersdefined for the 8086 plus the new registers introduced by the 80386: FS, GS,debug registers, control registers, and test registers. New instructionsthat explicitly operate on the segment registers FS and GS are available,and the new segment-override prefixes can be used to cause instructions toutilize FS and GS for address calculations. Instructions can utilize 32-bitoperands through the use of the operand size prefix.<P>The instruction codes that cause undefined opcode traps (interrupt 6)include instructions of the protected mode that manipulate or interrogate80386 selectors and descriptors; namely, <A HREF="VERR.htm">VERR</A>, <A HREF="VERR.htm">VERW</A>, <A HREF="LAR.htm">LAR</A>, <A HREF="LSL.htm">LSL</A>, <A HREF="LTR.htm">LTR</A>, <A HREF="STR.htm">STR</A>,<A HREF="LLDT.htm">LLDT</A>, and <A HREF="SLDT.htm">SLDT</A>. Programs executing in real-address mode are able to takeadvantage of the new applications-oriented instructions added to thearchitecture by the introduction of the 80186/80188, 80286 and 80386:<UL><LI> New instructions introduced by 80186/80188 and 80286.<UL><LI> <A HREF="PUSH.htm">PUSH</A> immediate data<LI> Push all and pop all (<A HREF="PUSHA.htm">PUSHA</A> and <A HREF="POPA.htm">POPA</A>)<LI> Multiply immediate data<LI> Shift and rotate by immediate count<LI> String I/O<LI> <A HREF="ENTER.htm">ENTER</A> and <A HREF="LEAVE.htm">LEAVE</A><LI> <A HREF="BOUND.htm">BOUND</A></UL><LI> New instructions introduced by 80386.<UL><LI> <A HREF="LGS.htm">LSS</A>, <A HREF="LGS.htm">LFS</A>, <A HREF="LGS.htm">LGS</A> instructions<LI> Long-displacement conditional jumps<LI> Single-bit instructions<LI> Bit scan<LI> Double-shift instructions<LI> Byte set on condition<LI> Move with sign/zero extension<LI> Generalized multiply<LI> <A HREF="MOVRS.htm">MOV</A> to and from control registers<LI> <A HREF="MOVRS.htm">MOV</A> to and from test registers<LI> <A HREF="MOVRS.htm">MOV</A> to and from debug registers</UL></UL><P><HR><P><B>up:</B> <A HREF="c14.htm">Chapter 14 -- 80386 Real-Address Mode</A><BR><B>prev:</B> <A HREF="s14_01.htm">14.1 Physical Address Formation</A><BR><B>next:</B> <A HREF="s14_03.htm">14.3 Interrupt and Exception Handling</A></BODY>⌨️ 快捷键说明
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