src/soc/decoder/helpers.py

   1 import unittest
   2 def exts(value, bits):
   3     sign = 1 << (bits - 1)
   4     return (value & (sign - 1)) - (value & sign)
   5
   6 def EXTS64(value):
   7     return exts(value, 32) & ((1<<64)-1)
   8
   9 def EXTZ64(value):
  10     return value & ((1<<32)-1)
  11
  12 def rotl(value, bits, wordlen):
  13     mask = (1 << wordlen) - 1
  14     bits = bits & (wordlen - 1)
  15     return ((value << bits) | (value >> (wordlen-bits))) & mask
  16
  17 def ROTL64(value, bits):
  18     return rotl(value, bits, 64)
  19
  20 def ROTL32(value, bits):
  21     return rotl(value, bits, 32)
  22
  23 def MASK(x, y):
  24     if x < y:
  25         x = 64-x
  26         y = 63-y
  27         mask_a = ((1<<x) - 1) & ((1<<64) - 1)
  28         mask_b = ((1<<y) - 1) & ((1<<64) - 1)
  29     else:
  30         x = 64-x
  31         y = 63-y
  32         mask_a = ((1<<x) - 1) & ((1<<64) - 1)
  33         mask_b = (~((1<<y) - 1)) & ((1<<64) - 1)
  34     return mask_a ^ mask_b
  35
  36
  37 class HelperTests(unittest.TestCase):
  38     def test_MASK(self):
  39         # Verified using rlwinm, rldicl, rldicr in qemu
  40         # li 1, -1
  41         # rlwinm reg, 1, 0, 5, 15
  42         self.assertHex(MASK(5+32, 15+32), 0x7ff0000)
  43         # rlwinm reg, 1, 0, 15, 5
  44         self.assertHex(MASK(15+32, 5+32), 0xfffffffffc01ffff)
  45         self.assertHex(MASK(30+32, 2+32), 0xffffffffe0000003)
  46         # rldicl reg, 1, 0, 37
  47         self.assertHex(MASK(37, 63), 0x7ffffff)
  48         self.assertHex(MASK(10, 63), 0x3fffffffffffff)
  49         self.assertHex(MASK(58, 63), 0x3f)
  50         # rldicr reg, 1, 0, 37
  51         self.assertHex(MASK(0, 37), 0xfffffffffc000000)
  52         self.assertHex(MASK(0, 10), 0xffe0000000000000)
  53         self.assertHex(MASK(0, 58), 0xffffffffffffffe0)
  54
  55     def test_ROTL64(self):
  56         # r1 = 0xdeadbeef12345678
  57         value = 0xdeadbeef12345678
  58
  59         # rldicl reg, 1, 10, 0
  60         self.assertHex(ROTL64(value, 10), 0xb6fbbc48d159e37a)
  61         # rldicl reg, 1, 35, 0
  62         self.assertHex(ROTL64(value, 35), 0x91a2b3c6f56df778)
  63         self.assertHex(ROTL64(value, 58), 0xe37ab6fbbc48d159)
  64         self.assertHex(ROTL64(value, 22), 0xbbc48d159e37ab6f)
  65
  66     def test_ROTL32(self):
  67         # r1 = 0xdeadbeef
  68         value = 0xdeadbeef
  69
  70         # rlwinm reg, 1, 10, 0, 31
  71         self.assertHex(ROTL32(value, 10), 0xb6fbbf7a)
  72         # rlwinm reg, 1, 17, 0, 31
  73         self.assertHex(ROTL32(value, 17), 0x7ddfbd5b)
  74         self.assertHex(ROTL32(value, 25), 0xdfbd5b7d)
  75         self.assertHex(ROTL32(value, 30), 0xf7ab6fbb)
  76
  77     def test_EXTS64(self):
  78         value_a = 0xdeadbeef # r1
  79         value_b = 0x73123456 # r2
  80         value_c = 0x80000000 # r3
  81
  82         self.assertHex(EXTS64(value_a), 0xffffffffdeadbeef)
  83         self.assertHex(EXTS64(value_b), value_b)
  84         self.assertHex(EXTS64(value_c), 0xffffffff80000000)
  85
  86
  87
  88     def assertHex(self, a, b):
  89         msg = "{:x} != {:x}".format(a, b)
  90         return self.assertEqual(a, b, msg)
  91
  92 if __name__ == '__main__':
  93     unittest.main()