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      1 /* Definitions of target machine for GNU compiler, for IBM S/390
      2    Copyright (C) 1999-2024 Free Software Foundation, Inc.
      3    Contributed by Hartmut Penner (hpenner (at) de.ibm.com) and
      4                   Ulrich Weigand (uweigand (at) de.ibm.com).
      5 
      6 This file is part of GCC.
      7 
      8 GCC is free software; you can redistribute it and/or modify it under
      9 the terms of the GNU General Public License as published by the Free
     10 Software Foundation; either version 3, or (at your option) any later
     11 version.
     12 
     13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
     14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
     15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     16 for more details.
     17 
     18 Under Section 7 of GPL version 3, you are granted additional
     19 permissions described in the GCC Runtime Library Exception, version
     20 3.1, as published by the Free Software Foundation.
     21 
     22 You should have received a copy of the GNU General Public License and
     23 a copy of the GCC Runtime Library Exception along with this program;
     24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     25 <http://www.gnu.org/licenses/>.  */
     26 
     27 #ifndef __s390x__
     28 
     29 #define EXPD(fp)	   (((fp.l.i[0]) >> 16) & 0x7FFF)
     30 #define EXPONENT_BIAS	   16383
     31 #define MANTISSA_BITS      112
     32 #define PRECISION          (MANTISSA_BITS + 1)
     33 #define SIGNBIT		   0x80000000
     34 #define SIGN(fp)	   ((fp.l.i[0]) & SIGNBIT)
     35 #define MANTD_HIGH_LL(fp)  ((fp.ll[0] & HIGH_LL_FRAC_MASK) | HIGH_LL_UNIT_BIT)
     36 #define MANTD_LOW_LL(fp)   (fp.ll[1])
     37 #define FRACD_ZERO_P(fp)   (!fp.ll[1] && !(fp.ll[0] & HIGH_LL_FRAC_MASK))
     38 #define HIGH_LL_FRAC_BITS  48
     39 #define HIGH_LL_UNIT_BIT   ((UDItype_x)1 << HIGH_LL_FRAC_BITS)
     40 #define HIGH_LL_FRAC_MASK  (HIGH_LL_UNIT_BIT - 1)
     41 #define LLONG_MAX       9223372036854775807LL
     42 #define LLONG_MIN       (-LLONG_MAX - 1LL)
     43 
     44 typedef int DItype_x __attribute__ ((mode (DI)));
     45 typedef unsigned int UDItype_x __attribute__ ((mode (DI)));
     46 typedef int SItype_x __attribute__ ((mode (SI)));
     47 typedef unsigned int USItype_x __attribute__ ((mode (SI)));
     48 
     49 union double_long {
     50   long double d;
     51   struct {
     52       SItype_x i[4]; /* 32 bit parts: 0 upper ... 3 lowest */
     53     } l;
     54   UDItype_x ll[2];   /* 64 bit parts: 0 upper, 1 lower */
     55 };
     56 
     57 static __inline__ void
     58 fexceptdiv (float d, float e)
     59 {
     60   __asm__ __volatile__ ("debr %0,%1" : : "f" (d), "f" (e) );
     61 }
     62 
     63 DItype_x __fixtfdi (long double a1);
     64 
     65 /* convert double to unsigned int */
     66 DItype_x
     67 __fixtfdi (long double a1)
     68 {
     69     register union double_long dl1;
     70     register int exp;
     71     register UDItype_x l;
     72 
     73     dl1.d = a1;
     74 
     75     /* +/- 0, denormalized */
     76     if (!EXPD (dl1))
     77       return 0;
     78 
     79     /* The exponent - considered the binary point at the right end of
     80        the mantissa.  */
     81     exp = EXPD (dl1) - EXPONENT_BIAS - MANTISSA_BITS;
     82 
     83     /* number < 1: If the mantissa would need to be right-shifted more bits than
     84        its size the result would be zero.  */
     85     if (exp <= -PRECISION)
     86       return 0;
     87 
     88     /* NaN: All exponent bits set and a nonzero fraction.  */
     89     if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1))
     90       {
     91 	/* C99 Annex F.4 requires an "invalid" exception to be thrown.  */
     92 	fexceptdiv (0.0, 0.0);
     93 	return 0x8000000000000000ULL;
     94       }
     95 
     96     /* One extra bit is needed for the unit bit which is appended by
     97        MANTD_HIGH_LL on the left of the matissa.  */
     98     exp += HIGH_LL_FRAC_BITS + 1;
     99 
    100     /* If the result would still need a left shift it will be too large
    101        to be represented.  Compared to the unsigned variant we have to
    102        take care that there is still space for the sign bit to be
    103        applied.  So we can only go on if there is a right-shift by one
    104        or more.  */
    105     if (exp >= 0)
    106       {
    107 	/* Don't throw an exception for -1p+63  */
    108 	if (!SIGN (dl1)
    109 	    || exp > 0
    110 	    || MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1)
    111 	    || (dl1.ll[0] & HIGH_LL_FRAC_MASK))
    112 	  /* C99 Annex F.4 requires an "invalid" exception to be thrown.  */
    113 	  fexceptdiv (0.0, 0.0);
    114 	return SIGN (dl1) ? LLONG_MIN : LLONG_MAX;
    115       }
    116 
    117     l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1)
    118         | MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1));
    119 
    120     return SIGN (dl1) ? -(l >> -exp) : l >> -exp;
    121 }
    122 #endif /* !__s390x__ */
    123