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The following patch fixes FAIL: gcc.dg/dfp/bitint-1.c (test for excess errors) FAIL: gcc.dg/dfp/bitint-2.c (test for excess errors) FAIL: gcc.dg/dfp/bitint-3.c (test for excess errors) FAIL: gcc.dg/dfp/bitint-4.c (test for excess errors) FAIL: gcc.dg/dfp/bitint-5.c (test for excess errors) FAIL: gcc.dg/dfp/bitint-6.c (test for excess errors) FAIL: gcc.dg/dfp/bitint-8.c (test for excess errors) FAIL: gcc.dg/dfp/int128-1.c (test for excess errors) FAIL: gcc.dg/dfp/int128-2.c (test for excess errors) FAIL: gcc.dg/dfp/int128-4.c (test for excess errors) on s390x-linux (with the 3 not yet posted patches). The patch does multiple things: 1) the routines were written for the DFP BID (binary integer decimal) format which is used on all arches but powerpc*/s390* (those use DPD - densely packed decimal format); as most of the code is actually the same for both BID and DPD formats, I haven't copied the sources + slightly modified them, but added the DPD support directly, + renaming of the exported symbols from __bid_* prefixed to __dpd_* prefixed that GCC expects on the DPD targets 2) while testing that I've found some big-endian issues in the existing support 3) testing also revealed that in some cases __builtin_clzll (~msb) was called with msb set to all ones, so invoking UB; apparently on aarch64 and x86 we were lucky and got some value that happened to work well, but that wasn't the case on s390x For 1), the patch uses two ~ 2KB tables to speed up the decoding/encoding. I haven't found such tables in what is added into libgcc.a, though they are in libdecnumber/bid/bid2dpd_dpd2bid.h, but there they are just huge and next to other huge tables - there is d2b which is like __dpd_d2bbitint in the patch but it uses 64-bit entries rather than 16-bit, then there is d2b2 with 64-bit entries like in d2b all multiplied by 1000, then d2b3 similarly multiplied by 1000000, then d2b4 similarly multiplied by 1000000000, then d2b5 similarly multiplied by 1000000000000ULL and d2b6 similarly multipled by 1000000000000000ULL. Arguably it can save some of the multiplications, but on the other side accesses memory which is unlikely in the caches, and the 2048 bytes in the patch vs. 24 times more for d2b is IMHO significant. For b2d, libdecnumber/bid/bid2dpd_dpd2bid.h has again b2d table like __dpd_b2dbitint in the patch, except that it has 64-bit entries rather than 16-bit (this time 1000 entries), but then has b2d2 which has the same entries shifted left by 10, then b2d3 shifted left by 20, b2d4 shifted left by 30 and b2d5 shifted left by 40. I can understand for d2b paying memory cost to speed up multiplications, but don't understand paying extra 4 * 8 * 1000 bytes (+ 6 * 1000 bytes for b2d not using ushort) just to avoid shifts. 2025-05-27 Jakub Jelinek <jakub@redhat.com> * config/t-softfp (softfp_bid_list): Don't guard with $(enable_decimal_float) == bid. * soft-fp/bitint.h (__bid_pow10bitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_pow10bitint. (__dpd_d2bbitint, __dpd_b2dbitint): Declare. * soft-fp/bitintpow10.c (__dpd_d2bbitint, __dpd_b2dbitint): New variables. * soft-fp/fixsdbitint.c (__bid_fixsdbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixsdbitint. Add DPD support. Fix big-endian support. * soft-fp/fixddbitint.c (__bid_fixddbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixddbitint. Add DPD support. Fix big-endian support. * soft-fp/fixtdbitint.c (__bid_fixtdbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixtdbitint. Add DPD support. Fix big-endian support. * soft-fp/fixsdti.c (__bid_fixsdbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixsdbitint. (__bid_fixsdti): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixsdti. * soft-fp/fixddti.c (__bid_fixddbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixddbitint. (__bid_fixddti): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixddti. * soft-fp/fixtdti.c (__bid_fixtdbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixtdbitint. (__bid_fixtdti): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixtdti. * soft-fp/fixunssdti.c (__bid_fixsdbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixsdbitint. (__bid_fixunssdti): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixunssdti. * soft-fp/fixunsddti.c (__bid_fixddbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixddbitint. (__bid_fixunsddti): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixunsddti. * soft-fp/fixunstdti.c (__bid_fixtdbitint): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixtdbitint. (__bid_fixunstdti): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_fixunstdti. * soft-fp/floatbitintsd.c (__bid_floatbitintsd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitintsd. Add DPD support. Avoid calling __builtin_clzll with 0 argument. Fix big-endian support. * soft-fp/floatbitintdd.c (__bid_floatbitintdd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitintdd. Add DPD support. Avoid calling __builtin_clzll with 0 argument. Fix big-endian support. * soft-fp/floatbitinttd.c (__bid_floatbitinttd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitinttd. Add DPD support. Avoid calling __builtin_clzll with 0 argument. Fix big-endian support. * soft-fp/floattisd.c (__bid_floatbitintsd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitintsd. (__bid_floattisd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floattisd. * soft-fp/floattidd.c (__bid_floatbitintdd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitintdd. (__bid_floattidd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floattidd. * soft-fp/floattitd.c (__bid_floatbitinttd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitinttd. (__bid_floattitd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floattitd. * soft-fp/floatuntisd.c (__bid_floatbitintsd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitintsd. (__bid_floatuntisd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatuntisd. * soft-fp/floatuntidd.c (__bid_floatbitintdd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitintdd. (__bid_floatuntidd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatuntidd. * soft-fp/floatuntitd.c (__bid_floatbitinttd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatbitinttd. (__bid_floatuntitd): For !defined(ENABLE_DECIMAL_BID_FORMAT) redefine to __dpd_floatuntitd.
58 lines
1.9 KiB
C
58 lines
1.9 KiB
C
/* Software floating-point emulation.
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Convert _Decimal128 to 128bit unsigned integer.
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Copyright (C) 2023-2025 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#include "soft-fp.h"
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#include "bitint.h"
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#if defined(__BITINT_MAXWIDTH__) && defined(__SIZEOF_INT128__)
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#ifndef ENABLE_DECIMAL_BID_FORMAT
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#define __bid_fixtdbitint __dpd_fixtdbitint
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#define __bid_fixunstdti __dpd_fixunstdti
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#endif
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extern void __bid_fixtdbitint (UBILtype *, SItype, _Decimal128);
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extern UTItype __bid_fixunstdti (_Decimal128);
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UTItype
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__bid_fixunstdti (_Decimal128 a)
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{
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UBILtype rb[128 / BIL_TYPE_SIZE];
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__bid_fixtdbitint (rb, 128, a);
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#if BIL_TYPE_SIZE == 128
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return rb[0];
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#elif BIL_TYPE_SIZE == 64
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return ((((UTItype) rb[BITINT_END (0, 1)]) << 64)
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| rb[BITINT_END (1, 0)]);
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#elif BIL_TYPE_SIZE == 32
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return ((((UTItype) rb[BITINT_END (0, 3)]) << 96)
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| (((UTItype) rb[BITINT_END (1, 2)]) << 64)
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| (((UTItype) rb[BITINT_END (2, 1)]) << 32)
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| rb[BITINT_END (3, 0)]);
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#else
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#error Unsupported UBILtype
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#endif
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}
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#endif
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