add comments

[soc.git] / src / soc / decoder / power_decoder.py

diff --git a/src/soc/decoder/power_decoder.py b/src/soc/decoder/power_decoder.py
index eb7c80a65f5d1ea9d6d1580b0bb699c315b2cfa9..d72a054fb9026937830cabf35e3fae4c16217d38 100644 (file)
--- a/src/soc/decoder/power_decoder.py
+++ b/src/soc/decoder/power_decoder.py
@@ -63,6 +63,7 @@ from collections import namedtuple
 from soc.decoder.power_fields import DecodeFields
 from soc.decoder.power_fieldsn import SigDecode, SignalBitRange
 
+
 Subdecoder = namedtuple("Subdecoder", ["pattern", "opcodes", "opint",
                                        "bitsel", "suffix", "subdecoders"])
 
@@ -177,6 +178,7 @@ class PowerDecoder(Elaboratable):
         comb = m.d.comb
 
         # note: default opcode is "illegal" as this is a combinatorial block
+        # this only works because OP_ILLEGAL=0 and the default (unset) is 0
 
         # go through the list of CSV decoders first
         for d in self.dec: