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# ScummVM - Graphic Adventure Engine
#
# ScummVM is the legal property of its developers, whose names
# are too numerous to list here. Please refer to the COPYRIGHT
# file distributed with this source distribution.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
import re
import op
class proc:
last_addr = 0xc000
def __init__(self, name):
self.name = name
self.calls = []
self.stmts = []
self.labels = set()
self.retlabels = set()
self.__label_re = re.compile(r'^(\S+):(.*)$')
self.offset = proc.last_addr
proc.last_addr += 4
def add_label(self, label):
self.stmts.append(op.label(label))
self.labels.add(label)
def remove_label(self, label):
try:
self.labels.remove(label)
except:
pass
for i in xrange(len(self.stmts)):
if isinstance(self.stmts[i], op.label) and self.stmts[i].name == label:
self.stmts[i] = op._nop(None)
return
def optimize_sequence(self, cls):
i = 0
stmts = self.stmts
while i < len(stmts):
if not isinstance(stmts[i], cls):
i += 1
continue
if i > 0 and isinstance(stmts[i - 1], op._rep): #skip rep prefixed instructions for now
i += 1
continue
j = i + 1
while j < len(stmts):
if not isinstance(stmts[j], cls):
break
j = j + 1
n = j - i
if n > 1:
print "Eliminate consequtive storage instructions at %u-%u" %(i, j)
for k in range(i+1,j):
stmts[k] = op._nop(None)
stmts[i].repeat = n
else:
i = j
i = 0
while i < len(stmts):
if not isinstance(stmts[i], op._rep):
i += 1
continue
if i + 1 >= len(stmts):
break
if isinstance(stmts[i + 1], cls):
stmts[i + 1].repeat = 'cx'
stmts[i + 1].clear_cx = True
stmts[i] = op._nop(None)
i += 1
return
def optimize(self, keep_labels=[]):
print "optimizing..."
#trivial simplifications
while len(self.stmts) and isinstance(self.stmts[-1], op.label):
print "stripping last label"
self.stmts.pop()
#mark labels that directly precede a ret
for i in range(len(self.stmts)):
if not isinstance(self.stmts[i], op.label):
continue
j = i
while j < len(self.stmts) and isinstance(self.stmts[j], (op.label, op._nop)):
j += 1
if j == len(self.stmts) or isinstance(self.stmts[j], op._ret):
print "Return label: %s" % (self.stmts[i].name,)
self.retlabels.add(self.stmts[i].name)
#merging push ax pop bx constructs
i = 0
while i + 1 < len(self.stmts):
a, b = self.stmts[i], self.stmts[i + 1]
if isinstance(a, op._push) and isinstance(b, op._pop):
ar, br = a.regs, b.regs
movs = []
while len(ar) and len(br):
src = ar.pop()
dst = br.pop(0)
movs.append(op._mov2(dst, src))
if len(br) == 0:
self.stmts.pop(i + 1)
print "merging %d push-pops into movs" %(len(movs))
for m in movs:
print "\t%s <- %s" %(m.dst, m.src)
self.stmts[i + 1:i + 1] = movs
if len(ar) == 0:
self.stmts.pop(i)
else:
i += 1
#eliminating unused labels
for s in list(self.stmts):
if not isinstance(s, op.label):
continue
print "checking label %s..." %s.name
used = s.name in keep_labels
if s.name not in self.retlabels:
for j in self.stmts:
if isinstance(j, op.basejmp) and j.label == s.name:
print "used"
used = True
break
if not used:
print self.labels
self.remove_label(s.name)
#removing duplicate rets and rets at end
for i in xrange(len(self.stmts)):
if isinstance(self.stmts[i], op._ret):
j = i+1
while j < len(self.stmts) and isinstance(self.stmts[j], op._nop):
j += 1
if j == len(self.stmts) or isinstance(self.stmts[j], op._ret):
self.stmts[i] = op._nop(None)
self.optimize_sequence(op._stosb);
self.optimize_sequence(op._stosw);
self.optimize_sequence(op._movsb);
self.optimize_sequence(op._movsw);
def add(self, stmt):
#print stmt
comment = stmt.rfind(';')
if comment >= 0:
stmt = stmt[:comment]
stmt = stmt.strip()
r = self.__label_re.search(stmt)
if r is not None:
#label
self.add_label(r.group(1).lower())
#print "remains: %s" %r.group(2)
stmt = r.group(2).strip()
if len(stmt) == 0:
return
s = stmt.split(None)
cmd = s[0]
cl = getattr(op, '_' + cmd)
arg = " ".join(s[1:]) if len(s) > 1 else str()
o = cl(arg)
self.stmts.append(o)
def __str__(self):
r = []
for i in self.stmts:
r.append(i.__str__())
return "\n".join(r)
def visit(self, visitor, skip = 0):
for i in xrange(skip, len(self.stmts)):
self.stmts[i].visit(visitor)
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