From 39aecf8b04104c5a2459e215033fbd11600a2eab Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Wed, 29 Sep 2021 19:09:21 +0100 Subject: [PATCH] morph exts/extz and add new "ext" function which takes shape arg --- src/nmutil/extend.py | 35 ++++++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 9 deletions(-) diff --git a/src/nmutil/extend.py b/src/nmutil/extend.py index 38b5e7d..9bff144 100644 --- a/src/nmutil/extend.py +++ b/src/nmutil/extend.py @@ -1,24 +1,41 @@ +# Copyright (C) Luke Kenneth Casson Leighton 2020,2021 +# License: LGPLv2+ """ - This work is funded through NLnet under Grant 2019-02-012 - - License: LGPLv3+ - +Provides sign/unsigned extension/truncation utility functions. +This work is funded through NLnet under Grant 2019-02-012 """ from nmigen import Repl, Cat, Const def exts(exts_data, width, fullwidth): + diff = fullwidth-width + if diff == 0: + return exts_data exts_data = exts_data[0:width] + if diff <= 0: + return exts_data[:fullwidth] topbit = exts_data[-1] - signbits = Repl(topbit, fullwidth-width) + signbits = Repl(topbit, diff) return Cat(exts_data, signbits) -def extz(exts_data, width, fullwidth): - exts_data = exts_data[0:width] +def extz(extz_data, width, fullwidth): + diff = fullwidth-width + if diff == 0: + return exts_data + extz_data = extz_data[0:width] + if diff <= 0: + return extz_data[:fullwidth] topbit = Const(0) - signbits = Repl(topbit, fullwidth-width) - return Cat(exts_data, signbits) + signbits = Repl(topbit, diff) + return Cat(extz_data, signbits) +def ext(data, shape, newwidth): + """extend/truncate data to new width, preserving sign + """ + width, signed = shape + if signed: + return exts(data, width, newwidth) + return extz(data, width, newwidth) -- 2.30.2