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/* @(#)s_floor.c 5.1 93/09/24 */ |
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/* |
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* ==================================================== |
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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* |
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* Developed at SunPro, a Sun Microsystems, Inc. business. |
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* Permission to use, copy, modify, and distribute this |
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* software is freely granted, provided that this notice |
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* is preserved. |
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* ==================================================== |
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*/ |
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/* |
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* truncf(x) |
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* Return x rounded toward 0 to integral value |
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* Method: |
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* Bit twiddling. |
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* Exception: |
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* Inexact flag raised if x not equal to truncf(x). |
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*/ |
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#include "math.h" |
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#include "math_private.h" |
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static const float huge = 1.0e30F; |
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float |
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truncf(float x) |
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{ |
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int32_t i0,jj0; |
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u_int32_t i; |
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GET_FLOAT_WORD(i0,x); |
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jj0 = ((i0>>23)&0xff)-0x7f; |
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if(jj0<23) { |
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if(jj0<0) { /* raise inexact if x != 0 */ |
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if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ |
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i0 &= 0x80000000; |
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} else { |
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i = (0x007fffff)>>jj0; |
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if((i0&i)==0) return x; /* x is integral */ |
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if(huge+x>0.0F) /* raise inexact flag */ |
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i0 &= (~i); |
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} |
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} else { |
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if(jj0==0x80) return x+x; /* inf or NaN */ |
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else return x; /* x is integral */ |
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} |
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SET_FLOAT_WORD(x,i0); |
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return x; |
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} |