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kernel/linux-rt-4.4.41/arch/x86/math-emu/reg_convert.c 1.59 KB
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  /*---------------------------------------------------------------------------+
   |  reg_convert.c                                                            |
   |                                                                           |
   |  Convert register representation.                                         |
   |                                                                           |
   | Copyright (C) 1992,1993,1994,1996,1997                                    |
   |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
   |                  E-mail   billm@suburbia.net                              |
   |                                                                           |
   |                                                                           |
   +---------------------------------------------------------------------------*/
  
  #include "exception.h"
  #include "fpu_emu.h"
  
  int FPU_to_exp16(FPU_REG const *a, FPU_REG *x)
  {
  	int sign = getsign(a);
  
  	*(long long *)&(x->sigl) = *(const long long *)&(a->sigl);
  
  	/* Set up the exponent as a 16 bit quantity. */
  	setexponent16(x, exponent(a));
  
  	if (exponent16(x) == EXP_UNDER) {
  		/* The number is a de-normal or pseudodenormal. */
  		/* We only deal with the significand and exponent. */
  
  		if (x->sigh & 0x80000000) {
  			/* Is a pseudodenormal. */
  			/* This is non-80486 behaviour because the number
  			   loses its 'denormal' identity. */
  			addexponent(x, 1);
  		} else {
  			/* Is a denormal. */
  			addexponent(x, 1);
  			FPU_normalize_nuo(x);
  		}
  	}
  
  	if (!(x->sigh & 0x80000000)) {
  		EXCEPTION(EX_INTERNAL | 0x180);
  	}
  
  	return sign;
  }