1 // SPDX-License-Identifier: GPL-2.0-only 2 /* IEEE754 floating point arithmetic 3 * single precision 4 */ 5 /* 6 * MIPS floating point support 7 * Copyright (C) 1994-2000 Algorithmics Ltd. 8 */ 9 10 #include "ieee754sp.h" 11 12 s64 ieee754sp_tlong(union ieee754sp x) 13 { 14 u32 residue; 15 int round; 16 int sticky; 17 int odd; 18 19 COMPXDP; /* <-- need 64-bit mantissa tmp */ 20 21 ieee754_clearcx(); 22 23 EXPLODEXSP; 24 FLUSHXSP; 25 26 switch (xc) { 27 case IEEE754_CLASS_SNAN: 28 case IEEE754_CLASS_QNAN: 29 ieee754_setcx(IEEE754_INVALID_OPERATION); 30 return ieee754di_indef(); 31 32 case IEEE754_CLASS_INF: 33 ieee754_setcx(IEEE754_INVALID_OPERATION); 34 return ieee754di_overflow(xs); 35 36 case IEEE754_CLASS_ZERO: 37 return 0; 38 39 case IEEE754_CLASS_DNORM: 40 case IEEE754_CLASS_NORM: 41 break; 42 } 43 if (xe >= 63) { 44 /* look for valid corner case */ 45 if (xe == 63 && xs && xm == SP_HIDDEN_BIT) 46 return -0x8000000000000000LL; 47 /* Set invalid. We will only use overflow for floating 48 point overflow */ 49 ieee754_setcx(IEEE754_INVALID_OPERATION); 50 return ieee754di_overflow(xs); 51 } 52 /* oh gawd */ 53 if (xe > SP_FBITS) { 54 xm <<= xe - SP_FBITS; 55 } else if (xe < SP_FBITS) { 56 if (xe < -1) { 57 residue = xm; 58 round = 0; 59 sticky = residue != 0; 60 xm = 0; 61 } else { 62 residue = xm << (32 - SP_FBITS + xe); 63 round = (residue >> 31) != 0; 64 sticky = (residue << 1) != 0; 65 xm >>= SP_FBITS - xe; 66 } 67 odd = (xm & 0x1) != 0x0; 68 switch (ieee754_csr.rm) { 69 case FPU_CSR_RN: 70 if (round && (sticky || odd)) 71 xm++; 72 break; 73 case FPU_CSR_RZ: 74 break; 75 case FPU_CSR_RU: /* toward +Infinity */ 76 if ((round || sticky) && !xs) 77 xm++; 78 break; 79 case FPU_CSR_RD: /* toward -Infinity */ 80 if ((round || sticky) && xs) 81 xm++; 82 break; 83 } 84 if ((xm >> 63) != 0) { 85 /* This can happen after rounding */ 86 ieee754_setcx(IEEE754_INVALID_OPERATION); 87 return ieee754di_overflow(xs); 88 } 89 if (round || sticky) 90 ieee754_setcx(IEEE754_INEXACT); 91 } 92 if (xs) 93 return -xm; 94 else 95 return xm; 96 } 97