| 1 | /* lround adapted to be llround for Newlib, 2009 by Craig Howland. */ |
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| 2 | /* |
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| 3 | * ==================================================== |
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| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 5 | * |
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| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 7 | * Permission to use, copy, modify, and distribute this |
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| 8 | * software is freely granted, provided that this notice |
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| 9 | * is preserved. |
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| 10 | * ==================================================== |
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| 11 | */ |
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| 12 | |
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| 13 | #include "fdlibm.h" |
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| 14 | |
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| 15 | #ifndef _DOUBLE_IS_32BITS |
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| 16 | |
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| 17 | long long int |
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| 18 | llround(double x) |
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| 19 | { |
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| 20 | __int32_t sign, exponent_less_1023; |
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| 21 | /* Most significant word, least significant word. */ |
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| 22 | __uint32_t msw, lsw; |
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| 23 | long long int result; |
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| 24 | |
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| 25 | EXTRACT_WORDS(msw, lsw, x); |
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| 26 | |
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| 27 | /* Extract sign. */ |
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| 28 | sign = ((msw & 0x80000000) ? -1 : 1); |
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| 29 | /* Extract exponent field. */ |
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| 30 | exponent_less_1023 = ((msw & 0x7ff00000) >> 20) - 1023; |
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| 31 | msw &= 0x000fffff; |
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| 32 | msw |= 0x00100000; |
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| 33 | |
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| 34 | /* exponent_less_1023 in [-1023,1024] */ |
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| 35 | if (exponent_less_1023 < 20) |
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| 36 | { |
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| 37 | /* exponent_less_1023 in [-1023,19] */ |
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| 38 | if (exponent_less_1023 < 0) |
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| 39 | { |
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| 40 | if (exponent_less_1023 < -1) |
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| 41 | return 0; |
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| 42 | else |
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| 43 | return sign; |
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| 44 | } |
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| 45 | else |
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| 46 | { |
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| 47 | /* exponent_less_1023 in [0,19] */ |
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| 48 | /* shift amt in [0,19] */ |
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| 49 | msw += 0x80000 >> exponent_less_1023; |
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| 50 | /* shift amt in [20,1] */ |
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| 51 | result = msw >> (20 - exponent_less_1023); |
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| 52 | } |
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| 53 | } |
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| 54 | else if (exponent_less_1023 < (8 * sizeof (long long int)) - 1) |
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| 55 | { |
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| 56 | /* 64bit longlong: exponent_less_1023 in [20,62] */ |
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| 57 | if (exponent_less_1023 >= 52) |
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| 58 | /* 64bit longlong: exponent_less_1023 in [52,62] */ |
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| 59 | /* 64bit longlong: shift amt in [32,42] */ |
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| 60 | result = ((long long int) msw << (exponent_less_1023 - 20)) |
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| 61 | /* 64bit longlong: shift amt in [0,10] */ |
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| 62 | | (lsw << (exponent_less_1023 - 52)); |
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| 63 | else |
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| 64 | { |
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| 65 | /* 64bit longlong: exponent_less_1023 in [20,51] */ |
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| 66 | unsigned int tmp = lsw |
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| 67 | /* 64bit longlong: shift amt in [0,31] */ |
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| 68 | + (0x80000000 >> (exponent_less_1023 - 20)); |
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| 69 | if (tmp < lsw) |
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| 70 | ++msw; |
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| 71 | /* 64bit longlong: shift amt in [0,31] */ |
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| 72 | result = ((long long int) msw << (exponent_less_1023 - 20)) |
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| 73 | /* ***64bit longlong: shift amt in [32,1] */ |
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| 74 | | SAFE_RIGHT_SHIFT (tmp, (52 - exponent_less_1023)); |
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| 75 | } |
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| 76 | } |
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| 77 | else |
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| 78 | /* Result is too large to be represented by a long long int. */ |
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| 79 | return (long long int)x; |
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| 80 | |
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| 81 | return sign * result; |
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| 82 | } |
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| 83 | |
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| 84 | #endif /* _DOUBLE_IS_32BITS */ |
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