From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id DF58D3858D39 for ; Sat, 2 Sep 2023 11:41:07 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org DF58D3858D39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693654867; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=75muPFZB0lfsL6FUgtTXwCn44+9VqPrXENij/4qyn5c=; b=THaFT4AdzDYGrm9QAD+H74AxkL6IegLu5c0IaDsg1z+9zOM0OR9Uh1pBhFAsG1BIoSNHy9 enbgC8wPm1dwSIcV28fEpZKAB0obUtMaA9tNHhfEhbWSw2FyRBS4pKvbE2mkzP9mRqFmbl 42o8LDr9AqSFPX8Xczh1CyxKd/+r7Q4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-267-zEY36UMxOwuwlOLkIBg0oQ-1; Sat, 02 Sep 2023 07:41:06 -0400 X-MC-Unique: zEY36UMxOwuwlOLkIBg0oQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8E6CC8DF4E4; Sat, 2 Sep 2023 11:41:05 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.45.224.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3A1382012F37; Sat, 2 Sep 2023 11:41:05 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 382Bf3ql2781677 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Sat, 2 Sep 2023 13:41:03 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 382Bf3O42781676; Sat, 2 Sep 2023 13:41:03 +0200 Date: Sat, 2 Sep 2023 13:41:02 +0200 From: Jakub Jelinek To: Joseph Myers Cc: Richard Biener , gcc-patches@gcc.gnu.org Subject: Re: [PATCH 14/12] libgcc _BitInt helper documentation [PR102989] Message-ID: Reply-To: Jakub Jelinek References: <409a2da3-1c2d-e62-6f7-8a3ec74871c7@codesourcery.com> <4746d3d-c45f-abf-c31d-6c3aa91e315@codesourcery.com> MIME-Version: 1.0 In-Reply-To: <4746d3d-c45f-abf-c31d-6c3aa91e315@codesourcery.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Fri, Sep 01, 2023 at 09:32:22PM +0000, Joseph Myers wrote: > This patch is OK with those fixes. Thanks, here is the updated patch. Queued with the rest of approved patches. 2023-09-02 Jakub Jelinek PR c/102989 gcc/ * doc/libgcc.texi (Bit-precise integer arithmetic functions): Document general rules for _BitInt support library functions and document __mulbitint3 and __divmodbitint4. (Conversion functions): Document __fix{s,d,x,t}fbitint, __floatbitint{s,d,x,t,h,b}f, __bid_fix{s,d,t}dbitint and __bid_floatbitint{s,d,t}d. libgcc/ * libgcc2.c (bitint_negate): Add function comment. * soft-fp/bitint.h (bitint_negate): Add function comment. (FP_TO_BITINT, FP_FROM_BITINT): Add comment explaining the macros. --- gcc/doc/libgcc.texi.jj 2023-01-16 11:52:16.115733593 +0100 +++ gcc/doc/libgcc.texi 2023-08-22 12:35:08.561348126 +0200 @@ -218,6 +218,51 @@ These functions return the number of bit These functions return the @var{a} byteswapped. @end deftypefn +@subsection Bit-precise integer arithmetic functions + +@code{_BitInt(@var{n})} library functions operate on arrays of limbs, where +each limb has @code{__LIBGCC_BITINT_LIMB_WIDTH__} bits and the limbs are +ordered according to @code{__LIBGCC_BITINT_ORDER__} ordering. The most +significant limb if @var{n} is not divisible by +@code{__LIBGCC_BITINT_LIMB_WIDTH__} contains padding bits which should be +ignored on read (sign or zero extended), but extended on write. For the +library functions, all bit-precise integers regardless of @var{n} are +represented like that, even when the target ABI says that for some small +@var{n} they should be represented differently in memory. A pointer +to the array of limbs argument is always accompanied with a bit size +argument. If that argument is positive, it is number of bits and the +number is assumed to be zero-extended to infinite precision, if that +argument is negative, it is negated number of bits above which all bits +are assumed to be sign-extended to infinite precision. These number of bits +arguments don't need to match actual @var{n} for the operation used in the +source, they could be lowered because of sign or zero extensions on the +input or because value-range optimization figures value will need certain +lower number of bits. For big-endian ordering of limbs, when lowering +the bit size argument the pointer argument needs to be adjusted as well. +Negative bit size argument should be always smaller or equal to @code{-2}, +because @code{signed _BitInt(1)} is not valid. +For output arguments, either the corresponding bit size argument should +be always positive (for multiplication and division), or is negative when +the output of conversion from floating-point value is signed and positive +when unsigned. The arrays of limbs output arguments point to should not +overlap any inputs, while input arrays of limbs can overlap. +@code{UBILtype} below stands for unsigned integer type with +@code{__LIBGCC_BITINT_LIMB_WIDTH__} bit precision. + +@deftypefn {Runtime Function} void __mulbitint3 (@code{UBILtype} *@var{ret}, int32_t @var{retprec}, const @code{UBILtype} *u, int32_t @var{uprec}, const @code{UBILtype} *v, int32_t @var{vprec}) +This function multiplies bit-precise integer operands @var{u} and @var{v} and stores +result into @var{retprec} precision bit-precise integer result @var{ret}. +@end deftypefn + +@deftypefn {Runtime Function} void __divmodbitint4 (@code{UBILtype} *@var{q}, int32_t @var{qprec}, @code{UBILtype} *@var{r}, int32_t @var{rprec}, const @code{UBILtype} *u, int32_t @var{uprec}, const @code{UBILtype} *v, int32_t @var{vprec}) +This function divides bit-precise integer operands @var{u} and @var{v} and stores +quotient into @var{qprec} precision bit-precise integer result @var{q} +(unless @var{q} is @code{NULL} and @var{qprec} is 0, in that case quotient +is not stored anywhere) and remainder into @var{rprec} precision bit-precise +integer result @var{r} (similarly, unless @var{r} is @code{NULL} and @var{rprec} +is 0). +@end deftypefn + @node Soft float library routines @section Routines for floating point emulation @cindex soft float library @@ -384,6 +429,27 @@ These functions convert @var{i}, an unsi These functions convert @var{i}, an unsigned long long, to floating point. @end deftypefn +@deftypefn {Runtime Function} void __fixsfbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, float @var{a}) +@deftypefnx {Runtime Function} void __fixdfbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, double @var{a}) +@deftypefnx {Runtime Function} void __fixxfbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, __float80 @var{a}) +@deftypefnx {Runtime Function} void __fixtfbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, _Float128 @var{a}) +These functions convert @var{a} to bit-precise integer @var{r}, rounding toward zero. +If @var{rprec} is positive, it converts to unsigned bit-precise integer and +negative values all become zero, if @var{rprec} is negative, it converts +to signed bit-precise integer. +@end deftypefn + +@deftypefn {Runtime Function} float __floatbitintsf (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} double __floatbitintdf (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} __float80 __floatbitintxf (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} _Float128 __floatbitinttf (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} _Float16 __floatbitinthf (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} __bf16 __floatbitintbf (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +These functions convert bit-precise integer @var{i} to floating point. If +@var{iprec} is positive, it is conversion from unsigned bit-precise integer, +otherwise from signed bit-precise integer. +@end deftypefn + @subsection Comparison functions There are two sets of basic comparison functions. @@ -707,6 +773,23 @@ These functions convert @var{i}, an unsi These functions convert @var{i}, an unsigned long, to decimal floating point. @end deftypefn +@deftypefn {Runtime Function} void __bid_fixsdbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, _Decimal32 @var{a}) +@deftypefnx {Runtime Function} void __bid_fixddbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, _Decimal64 @var{a}) +@deftypefnx {Runtime Function} void __bid_fixtdbitint (@code{UBILtype} *@var{r}, int32_t @var{rprec}, _Decimal128 @var{a}) +These functions convert @var{a} to bit-precise integer @var{r}, rounding toward zero. +If @var{rprec} is positive, it converts to unsigned bit-precise integer and +negative values all become zero, if @var{rprec} is negative, it converts +to signed bit-precise integer. So far implemented for BID format only. +@end deftypefn + +@deftypefn {Runtime Function} _Decimal32 __bid_floatbitintsd (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} _Decimal64 __bid_floatbitintdd (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +@deftypefnx {Runtime Function} _Decimal128 __bid_floatbitinttd (@code{UBILtype} *@var{i}, int32_t @var{iprec}) +These functions convert bit-precise integer @var{i} to decimal floating point. If +@var{iprec} is positive, it is conversion from unsigned bit-precise integer, +otherwise from signed bit-precise integer. So far implemented for BID format only. +@end deftypefn + @subsection Comparison functions @deftypefn {Runtime Function} int __dpd_unordsd2 (_Decimal32 @var{a}, _Decimal32 @var{b}) --- libgcc/libgcc2.c.jj 2023-08-22 11:21:31.549370982 +0200 +++ libgcc/libgcc2.c 2023-08-22 13:24:46.198998697 +0200 @@ -1640,6 +1640,8 @@ __mulbitint3 (UWtype *ret, SItype retpre #endif #ifdef L_divmodbitint4 +/* D = -S. */ + static void bitint_negate (UWtype *d, const UWtype *s, SItype n) { --- libgcc/soft-fp/bitint.h.jj 2023-08-22 11:21:31.583370543 +0200 +++ libgcc/soft-fp/bitint.h 2023-08-22 13:06:01.346092498 +0200 @@ -160,6 +160,9 @@ bitint_reduce_prec (const UBILtype **p, # define BITINT_END(be, le) (le) #endif +/* Negate N limbs from S into D. D and S should point to + the least significant limb. */ + static inline __attribute__((__always_inline__)) void bitint_negate (UBILtype *d, const UBILtype *s, SItype n) { @@ -175,6 +178,19 @@ bitint_negate (UBILtype *d, const UBILty while (--n); } +/* Common final part of __fix?fbitint conversion functions. + The A floating point value should have been converted using + soft-fp macros into RV, U##DI##type DI##_BITS precise normal + integral type and SHIFT, how many bits should that value be + shifted to the left. R is pointer to limbs array passed to the + function, RN number of limbs in it, ARPREC absolute value of + RPREC argument passed to it, RSIZE number of significant bits in RV. + RSIGNED is non-zero if the result is signed bit-precise integer, + otherwise zero. If OVF is true, instead of storing RV shifted left + by SHIFT bits and zero or sign extended store minimum or maximum + of the signed or unsigned bit-precise integer type or zero depending on if + RV contains the minimum or maximum signed or unsigned value or zero. */ + #define FP_TO_BITINT(r, rn, arprec, shift, rv, rsize, rsigned, ovf, DI) \ if (ovf) \ { \ @@ -232,6 +248,16 @@ bitint_negate (UBILtype *d, const UBILty * sizeof (UBILtype)); \ } +/* Common initial part of __floatbitint?f conversion functions. + I and IPREC are arguments passed to those functions, convert that + into a pair of DI##type IV integer and SHIFT, such that converting + IV to floating point and multiplicating that by pow (2, SHIFT) + gives the expected result. IV size needs to be chosen such that + it is larger than number of bits in floating-point mantissa and + contains there even at least a two bits below the mantissa for + rounding purposes. If any of the SHIFT bits shifted out is non-zero, + the least significant bit should be non-zero. */ + #define FP_FROM_BITINT(i, iprec, iv, shift, DI) \ do \ { \ Jakub