From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 121815 invoked by alias); 4 Feb 2019 16:44:25 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 121806 invoked by uid 89); 4 Feb 2019 16:44:25 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-lf1-f49.google.com Received: from mail-lf1-f49.google.com (HELO mail-lf1-f49.google.com) (209.85.167.49) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 04 Feb 2019 16:44:23 +0000 Received: by mail-lf1-f49.google.com with SMTP id i26so435224lfc.0 for ; Mon, 04 Feb 2019 08:44:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=1p7q/8g/FRub8Dli+nBep/jW/+uQoc3yjTI348L14YA=; b=UT83Dli5bm6RnZ82aMu1olUzdSMGRH4xbdyWdYzlj5uzmq/+IigTsIm8tL0yFxvb0B E3iY+uafaqlxazSic/mGyUjN1ErHVd8ajR0ikmXOyXn/EOjuUNrrKf5642MIIXjbmQo5 +qNJn4VWw5cUkkaMrSviOzY4/7kLFRjIJBgMM= MIME-Version: 1.0 References: In-Reply-To: From: Prathamesh Kulkarni Date: Mon, 04 Feb 2019 16:44:00 -0000 Message-ID: Subject: Re: About GSOC. To: Tejas Joshi Cc: GCC Development Content-Type: text/plain; charset="UTF-8" X-IsSubscribed: yes X-SW-Source: 2019-02/txt/msg00010.txt.bz2 On Mon, 4 Feb 2019 at 21:27, Tejas Joshi wrote: > > Thanks. > > Did you add an entry for roundeven in builtins.def ? > Yes, I did. > > Find here the attached patch.diff for which I did the changes to > implement roundeven. There might be some unnecessary changes and some > necessary changes which have not been made. You haven't called roundeven() in the patch. You'll need to add an entry in fold_const_call_ss() similar to real_ceil, and probably in other places too. Thanks, Prathamesh > > Regards, > -Tejas > > On Mon, 4 Feb 2019 at 20:36, Prathamesh Kulkarni > wrote: > > > > On Mon, 4 Feb 2019 at 20:10, Tejas Joshi wrote: > > > > > > Hello. > > > I have implemented roundeven function in real.c as follows: (and > > > respective changes in real.h) > > It's a better idea to include all changes in patch instead of copy-pasting. > > Use the command: > > git diff > patch.diff > > which will create a file called "patch.diff" containing the changes > > and send it as an attachment. > > > > > > /* Round X to nearest even integer towards zero. */ > > > > > > void > > > real_roundeven (REAL_VALUE_TYPE *r, format_helper fmt, > > > const REAL_VALUE_TYPE *x) > > > { > > > REAL_VALUE_TYPE t; > > > > > > do_fix_trunc (&t, x); > > > HOST_WIDE_INT i = real_to_integer (&t); > > > if(i % 2) > > > do_add (r, &t, &dconstm1, 0); > > > else > > > *r = t; > > > } > > > > > > Although I cant get it to test like > > > > > > int foo() > > > { > > > double x = __builtin_roundeven (3.5); > > > printf("%f",x); > > > return (int) x; > > > } > > > Because I do not know its dependencies through other files. I tried to > > > track them down by inspecting real_ceil function, but it also includes > > > other optimization procedures like folding. How do I know enough > > > declarations to be made in respective files? > > Did you add an entry for roundeven in builtins.def ? > > > > Thanks, > > Prathamesh > > > > > > Thanks. > > > -Tejas > > > > > > On Mon, 28 Jan 2019 at 22:33, Tejas Joshi wrote: > > > > > > > > Hello. > > > > Representations of real numbers in real.c are a little complex to > > > > understand right now for me. I am still trying to understand them and > > > > figure them out using gdb and cscope. Though conventions are given in > > > > comments in real.c, I will still be trying to figure it out. The > > > > equation and its bitwise representation is not pretty elaborated in > > > > any documentation I could find. > > > > > > > > x = s * b^e * \sum_{k=1}^p f_k * b^{-k} > > > > > > > > where > > > > s = sign (+- 1) > > > > b = base or radix, here always 2 > > > > e = exponent > > > > p = precision (the number of base-b digits in the significand) > > > > f_k = the digits of the significand. > > > > > > > > In mean time, I've tried real_round function to work like roundeven. I > > > > will try to submit a clean patch along with roundeven implemented > > > > separately with changes like in builtins.def, adding cases, etc. > > > > > > > > void > > > > real_round (REAL_VALUE_TYPE *r, format_helper fmt, > > > > const REAL_VALUE_TYPE *x) > > > > { > > > > #if 0 > > > > do_add (r, x, &dconsthalf, x->sign); > > > > do_fix_trunc (r, r); > > > > if (fmt) > > > > real_convert (r, fmt, r); > > > > #endif > > > > fprintf (stderr, "\nhere\n"); > > > > real_value z; > > > > do_fix_trunc (&z, x); > > > > HOST_WIDE_INT i = real_to_integer (&z); > > > > fprintf (stderr, "\n i = %ld\n", i); > > > > if (i % 2) > > > > do_add (r, &z, &dconstm1, 0); > > > > else > > > > *r = z; > > > > } > > > > > > > > Thanks. > > > > -Tejas > > > > > > > > On Sat, 26 Jan 2019 at 03:02, Joseph Myers wrote: > > > > > > > > > > On Sat, 26 Jan 2019, Tejas Joshi wrote: > > > > > > > > > > > function with byte-byte comparison which also include mpfr. (Correct > > > > > > me if I am wrong.) What is the significance of mpfr related to these > > > > > > internal representations? > > > > > > > > > > real.c provides a fixed-size representation of floating-point numbers that > > > > > allows for various non-IEEE formats supported by GCC, and also allows > > > > > functions from dfp.c to be used for decimal floating-point formats. > > > > > > > > > > MPFR is used in GCC to provide operations that are nontrivial to > > > > > implement, especially those that are nontrivial to implement in such a > > > > > fixed-size context. real.c operations wrap around MPFR ones where > > > > > appropriate, doing whatever's needed in cases where there are non-IEEE > > > > > semantics or sets of values. > > > > > > > > > > -- > > > > > Joseph S. Myers > > > > > joseph@codesourcery.com