src/openpower/xer.py

   1 # SPDX-License-Identifier: LGPLv3+
   2 # Funded by NLnet https://nlnet.nl/
   3
   4 # XXX TODO: get this into openpower/consts.py instead.
   5 # create the layout from an auto-created Enum XERb
   6 """ Record for XER as defined in
   7 Power ISA v3.1B Book I section 3.2.2 page 49(75)
   8
   9 XER fields in MSB0:
  10
  11 | Bits  | Mnemonic | Description      |
  12 |-------|----------|------------------|
  13 | 0:31  | &nbsp;   | Reserved         |
  14 | 32    | SO       | Summary Overflow |
  15 | 33    | OV       | Overflow         |
  16 | 34    | CA       | Carry            |
  17 | 35:43 | &nbsp;   | Reserved         |
  18 | 44    | OV32     | Overflow32       |
  19 | 45    | CA32     | Carry32          |
  20 | 46:56 | &nbsp;   | Reserved         |
  21 | 57:63 | &nbsp;   | Reserved         |
  22 """
  23
  24 from nmigen import Record
  25 from copy import deepcopy
  26 from openpower.util import log
  27 from openpower.decoder.selectable_int import (
  28     FieldSelectableInt, SelectableInt)
  29
  30
  31 class XERRecord(Record):
  32     layout = [("Reserved1", 18),
  33               ("CA32", 1),
  34               ("OV32", 1),
  35               ("Reserved2", 9),
  36               ("CA", 1),
  37               ("OV", 1),
  38               ("SO", 1),
  39               ("Reserved3", 32),
  40               ]
  41
  42     def __init__(self, name=None):
  43         super().__init__(name=name, layout=XERRecord.layout)
  44
  45
  46 class XERState(SelectableInt):
  47     def __init__(self, value=0):
  48         SelectableInt.__init__(self, value, 64)
  49         self.fsi = {}
  50         offs = 0
  51         # set up sub-fields from Record layout
  52         self.fsi = {}
  53         l = deepcopy(XERRecord.layout)
  54         l.reverse()
  55         for field, width in l:
  56             end = offs+width
  57             fs = tuple(range(offs, end))
  58             v = FieldSelectableInt(self, fs)
  59             self.fsi[field] = v
  60             offs = end
  61
  62     @property
  63     def SO(self):
  64         return self.fsi['SO']
  65
  66     @SO.setter
  67     def SO(self, value):
  68         self.fsi['SO'].eq(value)
  69
  70     @property
  71     def OV(self):
  72         return self.fsi['OV']
  73
  74     @OV.setter
  75     def OV(self, value):
  76         self.fsi['OV'].eq(value)
  77
  78     @property
  79     def CA(self):
  80         return self.fsi['CA']
  81
  82     @CA.setter
  83     def CA(self, value):
  84         self.fsi['CA'].eq(value)
  85
  86     @property
  87     def OV32(self):
  88         return self.fsi['OV32']
  89
  90     @OV32.setter
  91     def OV32(self, value):
  92         self.fsi['OV32'].eq(value)
  93
  94     @property
  95     def CA32(self):
  96         return self.fsi['CA32']
  97
  98     @CA32.setter
  99     def CA32(self, value):
 100         self.fsi['CA32'].eq(value)
 101
 102
 103 if __name__ == "__main__":
 104     from pprint import pprint
 105     print("XERRecord.layout:")
 106     pprint(XERRecord.layout)
 107     print("XERState.fsi:")
 108     pprint(XERState().fsi)