--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/ppci/target/basetarget.py	Sat Mar 01 15:40:31 2014 +0100
@@ -0,0 +1,154 @@
+from ppci.asmnodes import ASymbol, AInstruction, ANumber
+from ppci import CompilerError
+
+"""
+  Base classes for defining a target
+"""
+
+# Machine code interface:
+class Operand:
+   """ Single machine operand """
+   pass
+
+# standard immediates:
+
+class ImmBase:
+    def __init__(self, imm):
+        assert type(imm) is int
+        assert imm < self.Max()
+        self.imm = imm
+
+    @classmethod
+    def Max(cls):
+        return 2**cls.bits
+
+    @classmethod
+    def Create(cls, vop):
+        if type(vop) is ANumber and vop.number < cls.Max():
+            return cls(vop.number)
+
+
+class Imm3(ImmBase):
+    bits = 3
+
+
+class Imm7(ImmBase):
+    bits = 7
+
+
+class Imm8(ImmBase):
+    bits = 8
+
+
+class Imm32(ImmBase):
+    bits = 32
+
+
+class Instruction:
+    """ Base instruction class """
+    def encode(self):
+        return bytes()
+
+    def relocations(self):
+        return []
+
+    def symbols(self):
+        return []
+
+
+class Nop(Instruction):
+    """ Instruction that does nothing and has zero size """
+    def encode(self):
+        return bytes()
+
+
+class PseudoInstruction(Instruction):
+    pass
+
+
+class Label(PseudoInstruction):
+    def __init__(self, name):
+        self.name = name
+
+    def __repr__(self):
+        return '{}:'.format(self.name)
+
+    def symbols(self):
+        return [self.name]
+
+    @classmethod
+    def Create(cls, vop):
+        if type(vop) is ASymbol:
+            name = vop.name
+            return cls(name)
+
+
+class Comment(PseudoInstruction):
+    def __init__(self, txt):
+        self.txt = txt
+
+    def encode(self):
+        return bytes()
+
+    def __repr__(self):
+        return '; {}'.format(self.txt)
+
+
+class Alignment(PseudoInstruction):
+    def __init__(self, a):
+        self.align = a
+
+    def __repr__(self):
+        return 'ALIGN({})'.format(self.align)
+
+    def encode(self):
+        pad = []
+        # TODO
+        address = 0
+        while (address % self.align) != 0:
+            address += 1
+            pad.append(0)
+        return bytes(pad)
+
+
+class DebugInfo(PseudoInstruction):
+    def __init__(self, i):
+        self.info = i
+
+    def __repr__(self):
+        return 'DebugInfo: {}'.format(self.info)
+
+
+class Register(Operand):
+    def __init__(self, name):
+        self.name = name
+
+
+class Target:
+    def __init__(self, name, desc=''):
+        self.name = name
+        self.desc = desc
+        self.registers = []
+        self.byte_sizes = {'int' : 4}  # For front end!
+
+        # For assembler:
+        self.assembler_rules = []
+        self.asm_keywords = []
+
+    def add_keyword(self, kw):
+        self.asm_keywords.append(kw)
+
+    def add_instruction(self, rhs, f):
+        self.add_rule('instruction', rhs, f)
+
+    def add_rule(self, lhs, rhs, f):
+        self.assembler_rules.append((lhs, rhs, f))
+
+    def instruction(self, cls):
+        """ Decorator function that registers an instruction to this target """
+        self.addInstruction(cls)
+        return cls
+
+    def addInstruction(self, i):
+        pass
+