From: bugzilla-daemon@libre-riscv.org
To: libre-riscv-dev@lists.libre-riscv.org
Subject: [libre-riscv-dev] [Bug 278] POWER v3.0B spec ambiguity on EXTS and missing EXTZ
Date: Sun, 05 Apr 2020 04:10:36 +0000
Message-ID: <bug-278-13-4IIqeSMzgV@http.bugs.libre-riscv.org/> (raw)
In-Reply-To: <bug-278-13@http.bugs.libre-riscv.org/>
http://bugs.libre-riscv.org/show_bug.cgi?id=278
Jacob Lifshay <programmerjake@gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |programmerjake@gmail.com
--- Comment #1 from Jacob Lifshay <programmerjake@gmail.com> ---
Reply on openpower-hdl-cores:
http://lists.mailinglist.openpowerfoundation.org/pipermail/openpower-hdl-cores/2020-April/000022.html
On Sat, Apr 4, 2020, 07:16 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
wrote:
> continuing with the implementation of a simulator that is taken
> directly - and literally - from the pseudocode and definitions of
> functions in the spec, we have hit an "inconvenient" definition.
> EXTS, section 1.3.4, page 6:
>
> EXTS(x) Result of extending x on the left with sign
> bits
>
> the problem is illustrated by asking the very simple question, "how many
> bits?"
Maybe it would work to treat it as a conversion from a bitstring to a
mathematical integer (like a Python3 int) where it can then be converted
back to a bitstring when it is assigned to something with a size again?
You don't need an infinite number of hardware bits to represent the
mathematical integer, since you know the exact range the values fall in so
you can calculate exactly how many bits you need, sign/zero-extending as
needed when converting back to a bitstring.
Jacob
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
libre-riscv-dev mailing list
libre-riscv-dev@lists.libre-riscv.org
http://lists.libre-riscv.org/mailman/listinfo/libre-riscv-dev
next prev parent reply index
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-04 14:17 [libre-riscv-dev] [Bug 278] New: " bugzilla-daemon
2020-04-05 4:10 ` bugzilla-daemon [this message]
2020-04-05 10:08 ` [libre-riscv-dev] [Bug 278] " bugzilla-daemon
2020-04-05 16:27 ` bugzilla-daemon
2020-04-05 18:46 ` bugzilla-daemon
2020-04-05 18:50 ` bugzilla-daemon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bug-278-13-4IIqeSMzgV@http.bugs.libre-riscv.org/ \
--to=bugzilla-daemon@libre-riscv.org \
--cc=libre-riscv-dev@lists.libre-riscv.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Libre RISC-V Mailing list Archives (accessible via public-inbox)
Archives are clonable: git clone --mirror https://inbox.libre-soc.org/libre-riscv-dev
Example config snippet for mirrors
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git