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author | 2015-08-28 09:58:54 +0800 | |
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committer | 2015-09-01 12:44:00 +0800 | |
commit | e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch) | |
tree | 66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/seabios/scripts/vgafixup.py | |
parent | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (diff) |
Add qemu 2.4.0
Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Diffstat (limited to 'qemu/roms/seabios/scripts/vgafixup.py')
-rw-r--r-- | qemu/roms/seabios/scripts/vgafixup.py | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/qemu/roms/seabios/scripts/vgafixup.py b/qemu/roms/seabios/scripts/vgafixup.py new file mode 100644 index 000000000..2053cd5d7 --- /dev/null +++ b/qemu/roms/seabios/scripts/vgafixup.py @@ -0,0 +1,96 @@ +#!/usr/bin/env python +# Work around x86emu bugs by replacing problematic instructions. +# +# Copyright (C) 2012 Kevin O'Connor <kevin@koconnor.net> +# +# This file may be distributed under the terms of the GNU GPLv3 license. + +# The x86emu code widely used in Linux distributions when running Xorg +# in vesamode is known to have issues with "retl", "leavel", "entryl", +# "leal", and some variants of "calll". This code modifies those +# instructions that are known to be generated by gcc to avoid +# triggering the x86emu bugs. + +# It is also known that the Windows vgabios emulator has issues with +# addressing negative offsets to the %esp register. That has been +# worked around by not using the gcc parameter "-fomit-frame-pointer" +# when compiling. + +import sys, re + +# leal parameter regex - example string: -3(%edx,%eax,8), %eax +re_leal = re.compile( + r'^\s*(?P<offset>[^(]*?)\s*' + r'\(\s*(?P<base>[^,)]*?)\s*(?:,\s*(?P<index>[^,)]*?)\s*)?' + r'(?:,\s*(?P<scale>[^,)]*?)\s*)?\)\s*' + r',\s*(?P<dest>.*?)\s*$') + +# Find an alternate set of instructions for a given "leal" instruction +def handle_leal(sline): + m = re_leal.match(sline[5:]) + if m is None or m.group('index') == '%esp': + print("Unable to fixup leal instruction: %s" % (sline,)) + sys.exit(-1) + offset, base, index, scale, dest = m.group( + 'offset', 'base', 'index', 'scale', 'dest') + if dest == '%esp': + # If destination is %esp then just use 16bit leaw instead + return 'leaw %s\n' % (sline[5:].replace('%e', '%'),) + if not scale: + scale = '1' + scale = {1: 0, 2: 1, 4: 2, 8: 3}[int(scale, 0)] + # Try to rearrange arguments to simplify 'base' (to improve code gen) + if not scale and base == index: + base, index, scale = '', index, 1 + elif not index or (not scale and base in (dest, '%esp') and index != dest): + base, index, scale = index, base, 0 + # Produce instructions to calculate "leal" + insns = ['pushfw'] + if base != dest: + # Calculate "leal" directly in dest register + if index != dest: + insns.insert(0, 'movl %s, %s' % (index, dest)) + if scale: + insns.append('shll $%d, %s' % (scale, dest)) + if base: + if base == '%esp': + offset += '+2' + insns.append('addl %s, %s' % (base, dest)) + elif base == index: + # Use "imull" method + insns.append('imull $%d, %s' % ((1<<scale)+1, dest)) + else: + # Backup/restore index register and do scaling in index register + insns.append('pushl %s' % (index,)) + insns.append('shll $%d, %s' % (scale, index)) + insns.append('addl %s, %s' % (index, dest)) + insns.append('popl %s' % (index,)) + if offset and offset != '0': + insns.append('addl $%s, %s' % (offset, dest)) + insns.append('popfw\n') + return ' ; '.join(insns) + +def main(): + infilename, outfilename = sys.argv[1:] + infile = open(infilename, 'r') + out = [] + for line in infile: + sline = line.strip() + if sline == 'ret': + out.append('retw $2\n') + elif sline == 'leave': + out.append('movl %ebp, %esp ; popl %ebp\n') + elif sline.startswith('call'): + out.append('pushw %ax ; callw' + sline[4:] + '\n') + elif sline.startswith('leal'): + out.append(handle_leal(sline)) + #print("-> %s\n %s" % (sline, out[-1].strip())) + else: + out.append(line) + infile.close() + outfile = open(outfilename, 'w') + outfile.write(''.join(out)) + outfile.close() + +if __name__ == '__main__': + main() |