137 lines
2.2 KiB
C
137 lines
2.2 KiB
C
#include "fpi.h"
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/*
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* the following routines depend on memory format, not the machine
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*/
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void
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fpis2i(Internal *i, void *v)
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{
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Single *s = v;
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i->s = (*s & 0x80000000) ? 1: 0;
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if((*s & ~0x80000000) == 0){
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SetZero(i);
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return;
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}
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i->e = ((*s>>23) & 0x00FF) - SingleExpBias + ExpBias;
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i->h = (*s & 0x007FFFFF)<<(1+NGuardBits);
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i->l = 0;
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if(i->e)
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i->h |= HiddenBit;
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else
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i->e++;
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}
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void
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fpid2i(Internal *i, void *v)
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{
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Double *d = v;
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i->s = (d->h & 0x80000000) ? 1: 0;
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i->e = (d->h>>20) & 0x07FF;
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i->h = ((d->h & 0x000FFFFF)<<(4+NGuardBits))|((d->l>>25) & 0x7F);
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i->l = (d->l & 0x01FFFFFF)<<NGuardBits;
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if(i->e)
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i->h |= HiddenBit;
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else
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i->e++;
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}
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void
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fpiw2i(Internal *i, void *v)
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{
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Word w, word = *(Word*)v;
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short e;
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if(word < 0){
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i->s = 1;
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word = -word;
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}
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else
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i->s = 0;
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if(word == 0){
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SetZero(i);
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return;
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}
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if(word > 0){
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for (e = 0, w = word; w; w >>= 1, e++)
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;
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} else
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e = 32;
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if(e > FractBits){
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i->h = word>>(e - FractBits);
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i->l = (word & ((1<<(e - FractBits)) - 1))<<(2*FractBits - e);
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}
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else {
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i->h = word<<(FractBits - e);
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i->l = 0;
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}
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i->e = (e - 1) + ExpBias;
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}
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void
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fpii2s(void *v, Internal *i)
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{
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short e;
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Single *s = (Single*)v;
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fpiround(i);
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if(i->h & HiddenBit)
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i->h &= ~HiddenBit;
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else
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i->e--;
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*s = i->s ? 0x80000000: 0;
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e = i->e;
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if(e < ExpBias){
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if(e <= (ExpBias - SingleExpBias))
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return;
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e = SingleExpBias - (ExpBias - e);
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}
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else if(e >= (ExpBias + (SingleExpMax-SingleExpBias))){
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*s |= SingleExpMax<<23;
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return;
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}
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else
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e = SingleExpBias + (e - ExpBias);
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*s |= (e<<23)|(i->h>>(1+NGuardBits));
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}
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void
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fpii2d(void *v, Internal *i)
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{
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Double *d = (Double*)v;
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fpiround(i);
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if(i->h & HiddenBit)
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i->h &= ~HiddenBit;
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else
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i->e--;
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i->l = ((i->h & GuardMask)<<25)|(i->l>>NGuardBits);
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i->h >>= NGuardBits;
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d->h = i->s ? 0x80000000: 0;
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d->h |= (i->e<<20)|((i->h & 0x00FFFFFF)>>4);
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d->l = (i->h<<28)|i->l;
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}
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void
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fpii2w(Word *word, Internal *i)
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{
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Word w;
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short e;
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fpiround(i);
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e = (i->e - ExpBias) + 1;
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if(e <= 0)
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w = 0;
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else if(e > 31)
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w = 0x7FFFFFFF;
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else if(e > FractBits)
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w = (i->h<<(e - FractBits))|(i->l>>(2*FractBits - e));
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else
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w = i->h>>(FractBits-e);
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if(i->s)
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w = -w;
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*word = w;
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}
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