_fixunstfdi.c revision 1.5
1/* Definitions of target machine for GNU compiler, for IBM S/390 2 Copyright (C) 1999-2015 Free Software Foundation, Inc. 3 Contributed by Hartmut Penner (hpenner@de.ibm.com) and 4 Ulrich Weigand (uweigand@de.ibm.com). 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify it under 9the terms of the GNU General Public License as published by the Free 10Software Foundation; either version 3, or (at your option) any later 11version. 12 13GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14WARRANTY; without even the implied warranty of MERCHANTABILITY or 15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16for more details. 17 18Under Section 7 of GPL version 3, you are granted additional 19permissions described in the GCC Runtime Library Exception, version 203.1, as published by the Free Software Foundation. 21 22You should have received a copy of the GNU General Public License and 23a copy of the GCC Runtime Library Exception along with this program; 24see 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 SIGND(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 42typedef int DItype_x __attribute__ ((mode (DI))); 43typedef unsigned int UDItype_x __attribute__ ((mode (DI))); 44typedef int SItype_x __attribute__ ((mode (SI))); 45typedef unsigned int USItype_x __attribute__ ((mode (SI))); 46 47union double_long { 48 long double d; 49 struct { 50 SItype_x i[4]; /* 32 bit parts: 0 upper ... 3 lowest */ 51 } l; 52 UDItype_x ll[2]; /* 64 bit parts: 0 upper, 1 lower */ 53}; 54 55static __inline__ void 56fexceptdiv (float d, float e) 57{ 58 __asm__ __volatile__ ("debr %0,%1" : : "f" (d), "f" (e) ); 59} 60 61UDItype_x __fixunstfdi (long double a1); 62 63/* convert double to unsigned int */ 64UDItype_x 65__fixunstfdi (long double a1) 66{ 67 register union double_long dl1; 68 register int exp; 69 register UDItype_x l; 70 71 dl1.d = a1; 72 73 /* +/- 0, denormalized */ 74 if (!EXPD (dl1)) 75 return 0; 76 77 /* Negative. */ 78 if (SIGND (dl1)) 79 { 80 /* Value is <= -1.0 81 C99 Annex F.4 requires an "invalid" exception to be thrown. */ 82 if (EXPD (dl1) >= EXPONENT_BIAS) 83 fexceptdiv (0.0, 0.0); 84 return 0; 85 } 86 87 /* The exponent - considered the binary point at the right end of 88 the mantissa. */ 89 exp = EXPD (dl1) - EXPONENT_BIAS - MANTISSA_BITS; 90 91 /* number < 1: If the mantissa would need to be right-shifted more bits than 92 its size (plus the implied one bit on the left) the result would be 93 zero. */ 94 if (exp <= -PRECISION) 95 return 0; 96 97 /* NaN: All exponent bits set and a nonzero fraction. */ 98 if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1)) 99 { 100 /* C99 Annex F.4 requires an "invalid" exception to be thrown. */ 101 fexceptdiv (0.0, 0.0); 102 return 0; 103 } 104 105 /* One extra bit is needed for the unit bit which is appended by 106 MANTD_HIGH_LL on the left of the matissa. */ 107 exp += HIGH_LL_FRAC_BITS + 1; 108 109 /* If the result would still need a left shift it will be too 110 large to be represented. Infinities have all exponent bits set 111 and will end up here as well. */ 112 if (exp > 0) 113 { 114 /* C99 Annex F.4 requires an "invalid" exception to be thrown. */ 115 fexceptdiv (0.0, 0.0); 116 return 0xFFFFFFFFFFFFFFFFULL; 117 } 118 119 l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1) 120 | MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1)); 121 122 return l >> -exp; 123} 124 125#endif /* !__s390x__ */ 126