def getModRM(obj,Mod,RM,data):
opdsz = obj.misc['opdsz'] or 32
adrsz = obj.misc['adrsz'] or 32
seg = obj.misc['segreg']
if seg is None: seg=''
# r/16/32 case:
if Mod==0b11:
op1 = env.getreg(RM,opdsz)
return op1,data
# m/16/32 case:
if adrsz==32 and RM==0b100:
# read SIB byte in data:
if data.size<8: raise InstructionError(obj)
sib,data = data[0:8],data[8:data.size]
# add sib byte:
obj.bytes += pack(sib)
# decode base & scaled index
b = env.getreg(sib[0:3].int(),adrsz)
i = env.getreg(sib[3:6].int(),adrsz)
ss = 1<<(sib[6:8].int())
s = i*ss if not i.ref in ('esp','sp') else 0
else:
s = 0
if adrsz==32:
b = env.getreg(RM,adrsz)
else:
b = (env.bx+env.si,
env.bx+env.di,
env.bp+env.si,
env.bp+env.di,
env.si,
env.di,
env.bp,
env.bx)[RM]
# check [disp16/32] case:
if (b is env.ebp or b is env.bp) and Mod==0:
b=env.cst(0,adrsz)
Mod = 0b10
# now read displacement bytes:
if Mod==0b00:
d = 0
elif Mod==0b01:
if data.size<8: raise InstructionError(obj)
d = data[0:8]
data = data[8:data.size]
obj.bytes += pack(d)
d = d.signextend(adrsz).int(-1)
elif Mod==0b10:
if data.size<adrsz: raise InstructionError(obj)
d = data[0:adrsz]
obj.bytes += pack(d)
data = data[adrsz:data.size]
d = d.int(-1)
bs = b+s
if bs._is_cst and bs.v==0x0:
bs.v = d
bs.size = adrsz
d = 0
return env.mem(bs,opdsz,seg,d),data
def getModRM(obj,Mod,RM,data):
opdsz = obj.misc['opdsz'] or 32
adrsz = obj.misc['adrsz'] or 32
seg = obj.misc['segreg']
if seg is None: seg=''
# r/16/32 case:
if Mod==0b11:
op1 = env.getreg(RM,opdsz)
return op1,data
# m/16/32 case:
if adrsz==32 and RM==0b100:
# read SIB byte in data:
if data.size<8: raise InstructionError(obj)
sib,data = data[0:8],data[8:data.size]
# add sib byte:
obj.bytes += pack(sib)
# decode base & scaled index
b = env.getreg(sib[0:3].int(),adrsz)
i = env.getreg(sib[3:6].int(),adrsz)
ss = 1<<(sib[6:8].int())
s = i*ss if not i.ref in ('esp','sp') else 0
else:
s = 0
if adrsz==32:
b = env.getreg(RM,adrsz)
else:
b = (env.bx+env.si,
env.bx+env.di,
env.bp+env.si,
env.bp+env.di,
env.si,
env.di,
env.bp,
env.bx)[RM]
# check [disp16/32] case:
if (b is env.ebp or b is env.bp) and Mod==0:
b=env.cst(0,adrsz)
Mod = 0b10
# now read displacement bytes:
if Mod==0b00:
d = 0
elif Mod==0b01:
if data.size<8: raise InstructionError(obj)
d = data[0:8]
data = data[8:data.size]
obj.bytes += pack(d)
d = d.signextend(adrsz).int(-1)
elif Mod==0b10:
if data.size<adrsz: raise InstructionError(obj)
d = data[0:adrsz]
obj.bytes += pack(d)
data = data[adrsz:data.size]
d = d.int(-1)
bs = b+s
if bs._is_cst and bs.v==0x0:
bs.size = adrsz
bs.v = d & bs.mask
d = 0
return env.mem(bs,opdsz,seg,d),data
def getModRM(obj, Mod, RM, data):
opdsz = obj.misc['opdsz'] or env.internals['mode']
adrsz = obj.misc['adrsz'] or env.internals['mode']
seg = obj.misc['segreg']
if seg is None: seg = ''
# r/16/32 case:
if Mod == 0b11:
op1 = env.getreg(RM, opdsz)
return op1, data
# 32-bit SIB cases:
if adrsz == 32 and RM == 0b100:
# read SIB byte in data:
if data.size < 8: raise InstructionError(obj)
sib, data = data[0:8], data[8:data.size]
# add sib byte:
obj.bytes += pack(sib)
# decode base & scaled index
b = env.getreg(sib[0:3].int(), adrsz)
i = env.getreg(sib[3:6].int(), adrsz)
ss = 1 << (sib[6:8].int())
s = i * ss if not i.ref in ('esp', 'sp') else 0
else:
s = 0
if adrsz == 32:
b = env.getreg(RM, adrsz)
else:
b = (env.bx + env.si, env.bx + env.di, env.bp + env.si,
env.bp + env.di, env.si, env.di, env.bp, env.bx)[RM]
# check [disp16/32] case:
if (b is env.ebp or b is env.bp) and Mod == 0:
Mod = 0b10
bs = s + env.cst(0, adrsz)
elif s is 0:
bs = b
elif env.internals.get('keep_order'):
# Instead of doing bs = b+s, which will reorder arguments, we do
# the addition manually, and change 'prop' so the many future calls
# to 'simplify' does not reorder the arguments
from amoco.cas import expressions
bs = expressions.op('+', b, s)
bs.prop |= 16
else:
bs = b + s
# now read displacement bytes:
if Mod == 0b00:
d = 0
elif Mod == 0b01:
if data.size < 8: raise InstructionError(obj)
d = data[0:8]
data = data[8:data.size]
obj.bytes += pack(d)
d = d.signextend(adrsz).int(-1)
elif Mod == 0b10:
if data.size < adrsz: raise InstructionError(obj)
d = data[0:adrsz]
obj.bytes += pack(d)
data = data[adrsz:data.size]
d = d.int(-1)
if bs._is_cst and bs.v == 0x0:
bs.size = adrsz
bs.v = d & bs.mask
d = 0
return env.mem(bs, opdsz, seg, d), data