1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright (c) 1994-1997, by Sun Microsystems, Inc. 24 * All rights reserved. 25 */ 26 27 #include "quad.h" 28 29 #ifdef __sparcv9 30 #define _Q_qtos _Qp_qtos 31 #endif 32 33 /* 34 * _Q_qtos(x) returns (float)*x. 35 */ 36 float 37 _Q_qtos(const union longdouble *x) 38 { 39 union { 40 float f; 41 unsigned int l; 42 } u; 43 unsigned int xm, round, sticky, fsr, rm; 44 int subnormal, e; 45 46 xm = x->l.msw & 0x7fffffff; 47 48 /* get the rounding mode, fudging directed rounding modes */ 49 /* as though the result were positive */ 50 __quad_getfsrp(&fsr); 51 rm = fsr >> 30; 52 if (x->l.msw & 0x80000000) 53 rm ^= (rm >> 1); 54 55 /* handle nan, inf, and out-of-range cases */ 56 if (xm >= 0x407f0000) { 57 if (xm >= 0x7fff0000) { 58 if ((xm & 0xffff) | x->l.frac2 | x->l.frac3 | 59 x->l.frac4) { 60 /* x is nan */ 61 u.l = (x->l.msw & 0x80000000) | 0x7fc00000; 62 u.l |= ((xm & 0x7fff) << 7) | 63 (x->l.frac2 >> 25); 64 if (!(xm & 0x8000)) { 65 /* snan, signal invalid */ 66 if (fsr & FSR_NVM) { 67 __quad_fqtos(x, &u.f); 68 } else { 69 fsr = (fsr & ~FSR_CEXC) | 70 FSR_NVA | FSR_NVC; 71 __quad_setfsrp(&fsr); 72 } 73 } 74 return (u.f); 75 } 76 /* x is inf */ 77 u.l = (x->l.msw & 0x80000000) | 0x7f800000; 78 return (u.f); 79 } 80 /* x is too big, overflow */ 81 if (rm == FSR_RN || rm == FSR_RP) 82 u.l = 0x7f800000; 83 else 84 u.l = 0x7f7fffff; 85 u.l |= (x->l.msw & 0x80000000); 86 if (fsr & (FSR_OFM | FSR_NXM)) { 87 __quad_fqtos(x, &u.f); 88 } else { 89 fsr = (fsr & ~FSR_CEXC) | FSR_OFA | FSR_OFC | 90 FSR_NXA | FSR_NXC; 91 __quad_setfsrp(&fsr); 92 } 93 return (u.f); 94 } 95 96 subnormal = 0; 97 if (xm < 0x3f810000) { 98 if (xm < 0x3f690000) { 99 if (QUAD_ISZERO(*x)) { 100 u.l = (x->l.msw & 0x80000000); 101 return (u.f); 102 } 103 /* x is too small, underflow */ 104 u.l = ((rm == FSR_RP)? 1 : 0); 105 u.l |= (x->l.msw & 0x80000000); 106 if (fsr & (FSR_UFM | FSR_NXM)) { 107 __quad_fqtos(x, &u.f); 108 } else { 109 fsr = (fsr & ~FSR_CEXC) | FSR_UFA | FSR_UFC | 110 FSR_NXA | FSR_NXC; 111 __quad_setfsrp(&fsr); 112 } 113 return (u.f); 114 } 115 116 /* x is in the subnormal range for single */ 117 subnormal = 1; 118 u.l = 0x800000 | ((xm & 0xffff) << 7) | (x->l.frac2 >> 25); 119 e = 0x3f80 - (xm >> 16); 120 round = u.l & (1 << e); 121 sticky = (u.l & ((1 << e) - 1)) | (x->l.frac2 & 0x1ffffff) | 122 x->l.frac3 | x->l.frac4; 123 u.l >>= e + 1; 124 } else { 125 /* x is in the normal range for single */ 126 u.l = ((xm - 0x3f800000) << 7) | (x->l.frac2 >> 25); 127 round = x->l.frac2 & 0x1000000; 128 sticky = (x->l.frac2 & 0xffffff) | x->l.frac3 | x->l.frac4; 129 } 130 131 /* see if we need to round */ 132 fsr &= ~FSR_CEXC; 133 if (round | sticky) { 134 fsr |= FSR_NXC; 135 if (subnormal) 136 fsr |= FSR_UFC; 137 138 /* round up if necessary */ 139 if (rm == FSR_RP || (rm == FSR_RN && round && (sticky || 140 (u.l & 1)))) { 141 /* round up and check for overflow */ 142 if (++u.l >= 0x7f800000) 143 fsr |= FSR_OFC; 144 } 145 } 146 147 /* if result is exact and subnormal but underflow trapping is */ 148 /* enabled, signal underflow */ 149 else if (subnormal && (fsr & FSR_UFM)) 150 fsr |= FSR_UFC; 151 152 /* attach the sign and raise exceptions as need be */ 153 u.l |= (x->l.msw & 0x80000000); 154 if ((fsr & FSR_CEXC) & (fsr >> 23)) { 155 __quad_setfsrp(&fsr); 156 __quad_fqtos(x, &u.f); 157 } else { 158 fsr |= (fsr & 0x1f) << 5; 159 __quad_setfsrp(&fsr); 160 } 161 return (u.f); 162 } 163