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1 from target import Register, Instruction, Target
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2 from asmnodes import ASymbol, ANumber
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3 from ppci import CompilerError
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4 import struct, types
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5
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6 def u16(h):
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7 return struct.pack('<H', h)
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8
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9 armtarget = Target('arm')
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10
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11 # Add a custom operand mapping method:
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12 def mapOp(self, operand):
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13 if type(operand) is ASymbol:
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14 # try to map to register:
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15 regs = {}
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16 for r in self.registers:
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17 regs[r.name] = r
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18 if operand.name in regs:
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19 reg = regs[operand.name]
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20 return reg
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21 elif type(operand) is ANumber:
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22 return ArmImm(operand.number)
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23 raise CompilerError('Cannot map {0}'.format(operand))
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24
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25 armtarget.mapOperand = types.MethodType(mapOp, armtarget)
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26
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27 # Define:
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28 registers = 'r0,r1,r2,r3,r4,r5'
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29
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30 class ArmReg(Register):
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31 def __init__(self, num, name):
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32 super().__init__(name)
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33 self.num = num
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34
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35 class ArmImm:
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36 def __init__(self, i):
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37 self.i = i
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38
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39 # 8 bit registers:
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40 r4 = ArmReg(4, 'r4')
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41 armtarget.registers.append(r4)
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42
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43 class ArmInstruction(Instruction):
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44 pass
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45
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46 @armtarget.instruction
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47 class ldr_ins(ArmInstruction):
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48 mnemonic = 'ldr'
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49 opcode = 1337
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50
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51
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52 @armtarget.instruction
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53 class mov_ins(ArmInstruction):
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54 """ mov Rd, imm8, move immediate value into register """
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55 mnemonic = 'mov'
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56 opcode = 4 # 00100
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57 operands = (ArmReg, ArmImm)
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58 def __init__(self, r, imm):
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59 self.imm = imm.i
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60 self.r = r.num
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61 def encode(self):
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62 rd = self.r
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63 opcode = self.opcode
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64 imm8 = self.imm
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65 h = (opcode << 11) | (rd << 8) | imm8
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66 return u16(h)
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67
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68
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69 @armtarget.instruction
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70 class yield_ins(ArmInstruction):
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71 operands = ()
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72 mnemonic = 'yield'
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73 def encode(self):
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74 return u16(0xbf10)
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75
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