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 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include "quad.h" 30 31 #ifdef __sparcv9 32 #define _Q_qtos _Qp_qtos 33 #endif 34 35 /* 36 * _Q_qtos(x) returns (float)*x. 37 */ 38 float 39 _Q_qtos(const union longdouble *x) 40 { 41 union { 42 float f; 43 unsigned int l; 44 } u; 45 unsigned int xm, round, sticky, fsr, rm; 46 int subnormal, e; 47 48 xm = x->l.msw & 0x7fffffff; 49 50 /* get the rounding mode, fudging directed rounding modes */ 51 /* as though the result were positive */ 52 __quad_getfsrp(&fsr); 53 rm = fsr >> 30; 54 if (x->l.msw & 0x80000000) 55 rm ^= (rm >> 1); 56 57 /* handle nan, inf, and out-of-range cases */ 58 if (xm >= 0x407f0000) { 59 if (xm >= 0x7fff0000) { 60 if ((xm & 0xffff) | x->l.frac2 | x->l.frac3 | 61 x->l.frac4) { 62 /* x is nan */ 63 u.l = (x->l.msw & 0x80000000) | 0x7fc00000; 64 u.l |= ((xm & 0x7fff) << 7) | 65 (x->l.frac2 >> 25); 66 if (!(xm & 0x8000)) { 67 /* snan, signal invalid */ 68 if (fsr & FSR_NVM) { 69 __quad_fqtos(x, &u.f); 70 } else { 71 fsr = (fsr & ~FSR_CEXC) | 72 FSR_NVA | FSR_NVC; 73 __quad_setfsrp(&fsr); 74 } 75 } 76 return (u.f); 77 } 78 /* x is inf */ 79 u.l = (x->l.msw & 0x80000000) | 0x7f800000; 80 return (u.f); 81 } 82 /* x is too big, overflow */ 83 if (rm == FSR_RN || rm == FSR_RP) 84 u.l = 0x7f800000; 85 else 86 u.l = 0x7f7fffff; 87 u.l |= (x->l.msw & 0x80000000); 88 if (fsr & (FSR_OFM | FSR_NXM)) { 89 __quad_fqtos(x, &u.f); 90 } else { 91 fsr = (fsr & ~FSR_CEXC) | FSR_OFA | FSR_OFC | 92 FSR_NXA | FSR_NXC; 93 __quad_setfsrp(&fsr); 94 } 95 return (u.f); 96 } 97 98 subnormal = 0; 99 if (xm < 0x3f810000) { 100 if (xm < 0x3f690000) { 101 if (QUAD_ISZERO(*x)) { 102 u.l = (x->l.msw & 0x80000000); 103 return (u.f); 104 } 105 /* x is too small, underflow */ 106 u.l = ((rm == FSR_RP)? 1 : 0); 107 u.l |= (x->l.msw & 0x80000000); 108 if (fsr & (FSR_UFM | FSR_NXM)) { 109 __quad_fqtos(x, &u.f); 110 } else { 111 fsr = (fsr & ~FSR_CEXC) | FSR_UFA | FSR_UFC | 112 FSR_NXA | FSR_NXC; 113 __quad_setfsrp(&fsr); 114 } 115 return (u.f); 116 } 117 118 /* x is in the subnormal range for single */ 119 subnormal = 1; 120 u.l = 0x800000 | ((xm & 0xffff) << 7) | (x->l.frac2 >> 25); 121 e = 0x3f80 - (xm >> 16); 122 round = u.l & (1 << e); 123 sticky = (u.l & ((1 << e) - 1)) | (x->l.frac2 & 0x1ffffff) | 124 x->l.frac3 | x->l.frac4; 125 u.l >>= e + 1; 126 } else { 127 /* x is in the normal range for single */ 128 u.l = ((xm - 0x3f800000) << 7) | (x->l.frac2 >> 25); 129 round = x->l.frac2 & 0x1000000; 130 sticky = (x->l.frac2 & 0xffffff) | x->l.frac3 | x->l.frac4; 131 } 132 133 /* see if we need to round */ 134 fsr &= ~FSR_CEXC; 135 if (round | sticky) { 136 fsr |= FSR_NXC; 137 if (subnormal) 138 fsr |= FSR_UFC; 139 140 /* round up if necessary */ 141 if (rm == FSR_RP || (rm == FSR_RN && round && (sticky || 142 (u.l & 1)))) { 143 /* round up and check for overflow */ 144 if (++u.l >= 0x7f800000) 145 fsr |= FSR_OFC; 146 } 147 } 148 149 /* if result is exact and subnormal but underflow trapping is */ 150 /* enabled, signal underflow */ 151 else if (subnormal && (fsr & FSR_UFM)) 152 fsr |= FSR_UFC; 153 154 /* attach the sign and raise exceptions as need be */ 155 u.l |= (x->l.msw & 0x80000000); 156 if ((fsr & FSR_CEXC) & (fsr >> 23)) { 157 __quad_setfsrp(&fsr); 158 __quad_fqtos(x, &u.f); 159 } else { 160 fsr |= (fsr & 0x1f) << 5; 161 __quad_setfsrp(&fsr); 162 } 163 return (u.f); 164 } 165