comments on branch pipeline

[soc.git] / src / soc / fu / branch / main_stage.py

diff --git a/src/soc/fu/branch/main_stage.py b/src/soc/fu/branch/main_stage.py
index d4eecf37f80d3ec1ed93007d11d0aec5d9c828f3..cf7d48f45809cd2f48bf65a18855cff0f1995e1f 100644 (file)
--- a/src/soc/fu/branch/main_stage.py
+++ b/src/soc/fu/branch/main_stage.py
@@ -1,9 +1,13 @@
-# This stage is intended to do most of the work of executing Logical
-# instructions. This is OR, AND, XOR, POPCNT, PRTY, CMPB, BPERMD, CNTLZ
-# however input and output stages also perform bit-negation on input(s)
-# and output, as well as carry and overflow generation.
-# This module however should not gate the carry or overflow, that's up
-# to the output stage
+"""Branch Pipeline
+
+This stage is intended to do most of the work of executing branch
+instructions. This is OP_B, OP_B, OP_BCREG
+
+Links:
+* https://bugs.libre-soc.org/show_bug.cgi?id=313
+* https://bugs.libre-soc.org/show_bug.cgi?id=335
+* https://libre-soc.org/openpower/isa/branch/
+"""
 
 from nmigen import (Module, Signal, Cat, Mux, Const, Array)
 from nmutil.pipemodbase import PipeModBase
@@ -14,6 +18,7 @@ from soc.decoder.power_enums import InternalOp
 from soc.decoder.power_fields import DecodeFields
 from soc.decoder.power_fieldsn import SignalBitRange
 
+
 def br_ext(bd):
     """computes sign-extended NIA (assumes word-alignment)
     """