[Bug binutils/16891] New: libopcodes decodes x86 26 9B as 'fwait' not 'es'

[rsc at swtch dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16891

            Bug ID: 16891
           Summary: libopcodes decodes x86 26 9B as 'fwait' not 'es'
           Product: binutils
           Version: 2.24
            Status: NEW
          Severity: normal
          Priority: P2
         Component: binutils
          Assignee: unassigned at sourceware dot org
          Reporter: rsc at swtch dot com

Created attachment 7572
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7572&action=edit
test binary with 26 9B at beginning of text

libopcodes decodes the byte sequence 26 9B as the x86 instruction FWAIT of
length 1.

The 26 is a segment prefix (ES), and the 9B is the FWAIT. I could understand
fwait of length 2 if it wanted to include the segment prefix, but as it stands
now the disassembly claims that '26' by itself is fwait, which is certainly
untrue.

$ /usr/local/bin/x86_64-linux-elf-objdump -d -z test.elf

test.elf:     file format elf32-i386


Disassembly of section .text:

00008000 <.text>:
    8000:    26                       fwait
    8001:    9b                       fwait
...

-- 
You are receiving this mail because:
You are on the CC list for the bug.