src/soc/decoder/decode2execute1.py

   1 """Decode2ToExecute1Type
   2
   3 based on Anton Blanchard microwatt decode2.vhdl
   4
   5 """
   6 from nmigen import Signal, Record
   7 from nmutil.iocontrol import RecordObject
   8 from soc.decoder.power_enums import MicrOp, CryIn, Function, SPR, LDSTMode
   9
  10
  11 class Data(Record):
  12
  13     def __init__(self, width, name):
  14         name_ok = "%s_ok" % name
  15         layout = ((name, width), (name_ok, 1))
  16         Record.__init__(self, layout)
  17         self.data = getattr(self, name) # convenience
  18         self.ok = getattr(self, name_ok) # convenience
  19         self.data.reset_less = True # grrr
  20         self.reset_less = True # grrr
  21
  22     def ports(self):
  23         return [self.data, self.ok]
  24
  25
  26 class Decode2ToOperand(RecordObject):
  27
  28     def __init__(self, name=None):
  29
  30         RecordObject.__init__(self, name=name)
  31
  32         # current "state" (TODO: this in its own Record)
  33         self.msr = Signal(64, reset_less=True)
  34         self.cia = Signal(64, reset_less=True)
  35
  36         # instruction, type and decoded information
  37         self.insn = Signal(32, reset_less=True) # original instruction
  38         self.insn_type = Signal(MicrOp, reset_less=True)
  39         self.fn_unit = Signal(Function, reset_less=True)
  40         self.imm_data = Data(64, name="imm")
  41         self.lk = Signal(reset_less=True)
  42         self.rc = Data(1, "rc")
  43         self.oe = Data(1, "oe")
  44         self.invert_a = Signal(reset_less=True)
  45         self.zero_a = Signal(reset_less=True)
  46         self.input_carry = Signal(CryIn, reset_less=True)
  47         self.output_carry = Signal(reset_less=True)
  48         self.input_cr = Signal(reset_less=True)  # instr. has a CR as input
  49         self.output_cr = Signal(reset_less=True) # instr. has a CR as output
  50         self.invert_out = Signal(reset_less=True)
  51         self.is_32bit = Signal(reset_less=True)
  52         self.is_signed = Signal(reset_less=True)
  53         self.data_len = Signal(4, reset_less=True) # bytes
  54         self.byte_reverse  = Signal(reset_less=True)
  55         self.sign_extend  = Signal(reset_less=True)# do we need this?
  56         self.ldst_mode  = Signal(LDSTMode, reset_less=True) # LD/ST mode
  57         self.traptype  = Signal(5, reset_less=True) # see trap main_stage.py
  58         self.trapaddr  = Signal(13, reset_less=True)
  59         self.read_cr_whole = Signal(reset_less=True)
  60         self.write_cr_whole = Signal(reset_less=True)
  61         self.write_cr0 = Signal(reset_less=True)
  62
  63
  64 class Decode2ToExecute1Type(RecordObject):
  65
  66     def __init__(self, name=None, asmcode=True):
  67
  68         RecordObject.__init__(self, name=name)
  69
  70         if asmcode:
  71             self.asmcode = Signal(8, reset_less=True) # only for simulator
  72         self.write_reg = Data(5, name="rego")
  73         self.write_ea = Data(5, name="ea") # for LD/ST in update mode
  74         self.read_reg1 = Data(5, name="reg1")
  75         self.read_reg2 = Data(5, name="reg2")
  76         self.read_reg3 = Data(5, name="reg3")
  77         self.write_spr = Data(SPR, name="spro")
  78         self.read_spr1 = Data(SPR, name="spr1")
  79         #self.read_spr2 = Data(SPR, name="spr2") # only one needed
  80
  81         self.xer_in = Signal(reset_less=True)   # xer might be read
  82         self.xer_out = Signal(reset_less=True)  # xer might be written
  83
  84         self.read_fast1 = Data(3, name="fast1")
  85         self.read_fast2 = Data(3, name="fast2")
  86         self.write_fast1 = Data(3, name="fasto1")
  87         self.write_fast2 = Data(3, name="fasto2")
  88
  89         self.read_cr1 = Data(3, name="cr_in1")
  90         self.read_cr2 = Data(3, name="cr_in2")
  91         self.read_cr3 = Data(3, name="cr_in2")
  92         self.write_cr = Data(3, name="cr_out")
  93
  94         # decode operand data
  95         self.do = Decode2ToOperand(name)