102 lines
3.5 KiB
C
102 lines
3.5 KiB
C
/* Definitions of target machine for GNU compiler, for IBM S/390
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Copyright (C) 1999-2014 Free Software Foundation, Inc.
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Contributed by Hartmut Penner (hpenner@de.ibm.com) and
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Ulrich Weigand (uweigand@de.ibm.com).
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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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#define EXPD(fp) (((fp.l.i[0]) >> 16) & 0x7FFF)
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#define EXPONENT_BIAS 16383
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#define MANTISSA_BITS 112
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#define PRECISION (MANTISSA_BITS + 1)
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#define SIGNBIT 0x80000000
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#define SIGND(fp) ((fp.l.i[0]) & SIGNBIT)
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#define MANTD_HIGH_LL(fp) ((fp.ll[0] & HIGH_LL_FRAC_MASK) | HIGH_LL_UNIT_BIT)
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#define MANTD_LOW_LL(fp) (fp.ll[1])
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#define FRACD_ZERO_P(fp) (!fp.ll[1] && !(fp.ll[0] & HIGH_LL_FRAC_MASK))
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#define HIGH_LL_FRAC_BITS 48
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#define HIGH_LL_UNIT_BIT ((UDItype_x)1 << HIGH_LL_FRAC_BITS)
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#define HIGH_LL_FRAC_MASK (HIGH_LL_UNIT_BIT - 1)
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typedef int DItype_x __attribute__ ((mode (DI)));
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typedef unsigned int UDItype_x __attribute__ ((mode (DI)));
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typedef int SItype_x __attribute__ ((mode (SI)));
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typedef unsigned int USItype_x __attribute__ ((mode (SI)));
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union double_long {
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long double d;
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struct {
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SItype_x i[4]; /* 32 bit parts: 0 upper ... 3 lowest */
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} l;
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UDItype_x ll[2]; /* 64 bit parts: 0 upper, 1 lower */
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};
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DItype_x __fixtfdi (long double a1);
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/* convert double to unsigned int */
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DItype_x
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__fixtfdi (long double a1)
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{
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register union double_long dl1;
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register int exp;
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register UDItype_x l;
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dl1.d = a1;
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/* +/- 0, denormalized */
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if (!EXPD (dl1))
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return 0;
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/* The exponent - considered the binary point at the right end of
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the mantissa. */
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exp = EXPD (dl1) - EXPONENT_BIAS - MANTISSA_BITS;
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/* number < 1: If the mantissa would need to be right-shifted more bits than
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its size the result would be zero. */
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if (exp <= -PRECISION)
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return 0;
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/* NaN: All exponent bits set and a nonzero fraction. */
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if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1))
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return 0x8000000000000000ULL;
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/* One extra bit is needed for the unit bit which is appended by
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MANTD_HIGH_LL on the left of the matissa. */
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exp += HIGH_LL_FRAC_BITS + 1;
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/* If the result would still need a left shift it will be too large
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to be represented. Compared to the unsigned variant we have to
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take care that there is still space for the sign bit to be
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applied. So we can only go on if there is a right-shift by one
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or more. */
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if (exp >= 0)
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{
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l = 1ULL << 63; /* long long min */
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return SIGND (dl1) ? l : l - 1;
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}
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l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1)
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| MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1));
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return SIGND (dl1) ? -(l >> -exp) : l >> -exp;
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}
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