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authorYang Zhang <yang.z.zhang@intel.com>2015-08-28 09:58:54 +0800
committerYang Zhang <yang.z.zhang@intel.com>2015-09-01 12:44:00 +0800
commite44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch)
tree66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/seabios/scripts/vgafixup.py
parent9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (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.py96
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
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+++ 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()