[RFA]: opcodes / i386 disassembler

[RFA]: opcodes / i386 disassembler

[Michael Snyder]

Would the following be acceptable?  Assuming I provided an
suitable ChangeLog entry?

Index: i386-dis.c
===================================================================
RCS file: /cvs/cvsfiles/devo/opcodes/i386-dis.c,v
retrieving revision 1.51
diff -p -r1.51 i386-dis.c
*** i386-dis.c	2000/04/05 20:16:40	1.51
--- i386-dis.c	2000/07/21 01:40:08
*************** You should have received a copy of the G
*** 18,38 ****
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  
! /*
!  * 80386 instruction printer by Pace Willisson (pace@prep.ai.mit.edu)
!  * July 1988
!  *  modified by John Hassey (hassey@dg-rtp.dg.com)
!  */
! 
! /*
!  * The main tables describing the instructions is essentially a copy
!  * of the "Opcode Map" chapter (Appendix A) of the Intel 80386
!  * Programmers Manual.  Usually, there is a capital letter, followed
!  * by a small letter.  The capital letter tell the addressing mode,
!  * and the small letter tells about the operand size.  Refer to
!  * the Intel manual for details.
!  */
  
  #include "dis-asm.h"
  #include "sysdep.h"
  #include "opintl.h"
--- 18,34 ----
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  
! /* 80386 instruction printer by Pace Willisson (pace@prep.ai.mit.edu)
!    July 1988, modified by John Hassey (hassey@dg-rtp.dg.com).  */
  
+ /* The main tables describing the instructions is essentially a copy
+    of the "Opcode Map" chapter (Appendix A) of the Intel 80386
+    Programmers Manual and the Pentium(TM) Family User's Manual.
+    Usually, there is a capital letter, followed by a small letter.
+    The capital letter tell the addressing mode, and the small letter
+    tells about the operand size.  Refer to the Intel manual for
+    details.  */
+ 
  #include "dis-asm.h"
  #include "sysdep.h"
  #include "opintl.h"
*************** static const struct dis386 dis386_att[] 
*** 496,502 ****
    /* 80 */
    { GRP1b },
    { GRP1S },
!   { "(bad)",	XX, XX, XX },
    { GRP1Ss },
    { "testB",	Eb, Gb, XX },
    { "testS",	Ev, Gv, XX },
--- 492,509 ----
    /* 80 */
    { GRP1b },
    { GRP1S },
!   /* this one is blank in appendix A of the 386 book, and given as
!      "MOVB AL, imm8 in appendix A of the Pentium book with a footnote
!      saying "Reserved"; it *should* be "Immediate Grp1, Ev, Ib"
!      according to an Intel person who says it'll be fixed in the -004
!      version of the Pentium book.
! 
!      The trick here is that 0x80 sets neither the "s" nor the "w" bit,
!      while 0x82 sets the "s" bit but not the "w" bit.  However, if the
!      "w" bit isn't set, the setting of the "s" bit is irrelevant, as
!      the operands are one byte long, so there's no sign-extension to be
!      done. */
!   { GRP1b  },
    { GRP1Ss },
    { "testB",	Eb, Gb, XX },
    { "testS",	Ev, Gv, XX },
*************** static const struct dis386 dis386_twobyt
*** 968,974 ****
    { "(bad)", XX, XX, XX },
    { "(bad)", XX, XX, XX },
    /* 20 */
!   /* these are all backward in appendix A of the intel book */
    { "movL", Rd, Cd, XX },
    { "movL", Rd, Dd, XX },
    { "movL", Cd, Rd, XX },
--- 975,982 ----
    { "(bad)", XX, XX, XX },
    { "(bad)", XX, XX, XX },
    /* 20 */
!   /* these are all backward in appendix A of the intel book,
!      but correct in appendix A of the Pentium book.  */
    { "movL", Rd, Cd, XX },
    { "movL", Rd, Dd, XX },
    { "movL", Cd, Rd, XX },

Re: [RFA]: opcodes / i386 disassembler

[Alan Modra]

On Thu, 20 Jul 2000, Michael Snyder wrote:

> Would the following be acceptable?  Assuming I provided an
> suitable ChangeLog entry?

Yes.  Please check it in.  The x86 instruction set has many of these cases
where there's more than one encoding of an instruction.  Some people even
used this feature to store covert messages in code - eg. to brand code as
being produced by a certain assembler.

Alan Modra
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