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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [config/] [arm/] [fp16.c] - Rev 333
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/* Half-float conversion routines. Copyright (C) 2008, 2009 Free Software Foundation, Inc. Contributed by CodeSourcery. This file is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This file is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */ static inline unsigned short __gnu_f2h_internal(unsigned int a, int ieee) { unsigned short sign = (a >> 16) & 0x8000; int aexp = (a >> 23) & 0xff; unsigned int mantissa = a & 0x007fffff; unsigned int mask; unsigned int increment; if (aexp == 0xff) { if (!ieee) return sign; return sign | 0x7e00 | (mantissa >> 13); } if (aexp == 0 && mantissa == 0) return sign; aexp -= 127; /* Decimal point between bits 22 and 23. */ mantissa |= 0x00800000; if (aexp < -14) { mask = 0x007fffff; if (aexp < -25) aexp = -26; else if (aexp != -25) mask >>= 24 + aexp; } else mask = 0x00001fff; /* Round. */ if (mantissa & mask) { increment = (mask + 1) >> 1; if ((mantissa & mask) == increment) increment = mantissa & (increment << 1); mantissa += increment; if (mantissa >= 0x01000000) { mantissa >>= 1; aexp++; } } if (ieee) { if (aexp > 15) return sign | 0x7c00; } else { if (aexp > 16) return sign | 0x7fff; } if (aexp < -24) return sign; if (aexp < -14) { mantissa >>= -14 - aexp; aexp = -14; } /* We leave the leading 1 in the mantissa, and subtract one from the exponent bias to compensate. */ return sign | (((aexp + 14) << 10) + (mantissa >> 13)); } unsigned int __gnu_h2f_internal(unsigned short a, int ieee) { unsigned int sign = (unsigned int)(a & 0x8000) << 16; int aexp = (a >> 10) & 0x1f; unsigned int mantissa = a & 0x3ff; if (aexp == 0x1f && ieee) return sign | 0x7f800000 | (mantissa << 13); if (aexp == 0) { int shift; if (mantissa == 0) return sign; shift = __builtin_clz(mantissa) - 21; mantissa <<= shift; aexp = -shift; } return sign | (((aexp + 0x70) << 23) + (mantissa << 13)); } unsigned short __gnu_f2h_ieee(unsigned int a) { return __gnu_f2h_internal(a, 1); } unsigned int __gnu_h2f_ieee(unsigned short a) { return __gnu_h2f_internal(a, 1); } unsigned short __gnu_f2h_alternative(unsigned int x) { return __gnu_f2h_internal(x, 0); } unsigned int __gnu_h2f_alternative(unsigned short a) { return __gnu_h2f_internal(a, 0); }
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