Various errors in `operation.Operand`

[845977]

Error 1: Memory operand type destroyed by set_dst / set_src

_parse_type correctly sets self.type = op_mem for [dst] and [src] placeholders, but both set_dst and set_src unconditionally overwrite self.type to op_reg (or op_imm) when a concrete value is provided, discarding the memory type entirely.

Error 2: set_dst rejects immediate values

rop3/rop3/operation.py

Lines 250 to 254 in 95f6cb9

	def set_dst(self, dst):
	if self.is_dst():
	self.reg = dst
	self.generic = False
	self.type = arch_singleton.arch.op_reg

set_src tries _parse_imm before falling back to a register name, so --src 4 or --src 0x10 correctly produces an op_imm operand. set_dst had no equivalent and should do the same.

Error 3: Generic mem addresses can be resolved into immediates

rop3/rop3/operation.py

Lines 274 to 275 in 95f6cb9

	if self.generic and self.is_src() and operand.type == arch_singleton.arch.op_imm:
	return (True, operand.value.imm)

This is not desired behaviour, mov rax, 0xCAFE is not a ROPLang load.

[ricardojrdez]

Fixed in #35 (merged as c0fd559).