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/*
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Crown Copyright (c) 1997
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This TenDRA(r) Computer Program is subject to Copyright
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owned by the United Kingdom Secretary of State for Defence
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acting through the Defence Evaluation and Research Agency
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(DERA). It is made available to Recipients with a
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royalty-free licence for its use, reproduction, transfer
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to other parties and amendment for any purpose not excluding
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product development provided that any such use et cetera
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shall be deemed to be acceptance of the following conditions:-
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(1) Its Recipients shall ensure that this Notice is
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reproduced upon any copies or amended versions of it;
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(2) Any amended version of it shall be clearly marked to
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show both the nature of and the organisation responsible
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for the relevant amendment or amendments;
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(3) Its onward transfer from a recipient to another
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party shall be deemed to be that party's acceptance of
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these conditions;
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(4) DERA gives no warranty or assurance as to its
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quality or suitability for any purpose and DERA accepts
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no liability whatsoever in relation to any use to which
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it may be put.
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*/
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/*
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** float.c
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*/
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#include "config.h"
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#include "common_types.h"
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#include "flpttypes.h"
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#include "flpt.h"
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#include "expmacs.h"
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#include "shapemacs.h"
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#include "tags.h"
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#include "float.h"
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#define is_negative(x) (x.sign<0)
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/*
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This function takes an exp _e_ corresponding to a real_tag, and
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returns the floating point value referenced, by reading it from
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the flptnos[] array in the correct format.
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*/
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#if (FBASE == 10)
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char * floating_value
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PROTO_N ( ( e ) )
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PROTO_T ( exp e )
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{
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int ref = no(e);
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unsigned char *frac = (flptnos[ref].mant);
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char *result = (char*)xcalloc(128,sizeof(char*));
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int n,j;
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int pos=0;
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/* find end of value */
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for(n=MANT_SIZE-1;(n>1) && (frac[n]==0);n--);
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if( is_negative(flptnos[ref]) )
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result[pos++]='-';
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result[pos++]=frac[0]+'0';
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result[pos++]='.';
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for(j=1;j<=n;++pos,++j)
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result[pos] = frac[j]+'0';
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if(flptnos[ref].exp != 0){
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char *expstr=(char*)xcalloc(20,sizeof(char));
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sprintf(expstr,"E%ld",flptnos[ref].exp);
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strcat(result,expstr);
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}
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return result;
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}
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#endif
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/*
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Return true if the floating point constant produced by the
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make_floating construct is an IEEE denormal. Denormals are
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identified by having a non-zero fraction and a zero exponent.
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*/
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bool is_denormal
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PROTO_N ( ( e ) )
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PROTO_T ( exp e )
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{
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int fraction;
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int exponent;
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int fv = name(sh(e)) - shrealhd;
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bool result;
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r2l ieeeflt = real2longs_IEEE(&flptnos[no(e)],fv);
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Assert(name(e) == real_tag);
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switch(name(sh(e))){
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case shrealhd:
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exponent = ieeeflt.i1 & 0x7f800000;
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fraction = ieeeflt.i1 & ~0xff800000;
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break;
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case realhd:
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exponent = ieeeflt.i2 & 0x7ff00000;
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fraction = (ieeeflt.i2 & ~0xfff00000) | ieeeflt.i1;
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break;
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default:
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failer("Invalid floating point variety");
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break;
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}
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result = (exponent == 0) && (fraction != 0);
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return result;
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}
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