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#include <u.h>
#include <libc.h>
#include <bio.h>
#include <mach.h>
/*
* These routines assume that if the number is representable
* in IEEE floating point, it will be representable in the native
* double format. Naive but workable, probably.
*/
int
ieeeftoa64(char *buf, uint n, u32int h, u32int l)
{
double fr;
int exp;
if (n <= 0)
return 0;
if(h & (1UL<<31)){
*buf++ = '-';
h &= ~(1UL<<31);
}else
*buf++ = ' ';
n--;
if(l == 0 && h == 0)
return snprint(buf, n, "0.");
exp = (h>>20) & ((1L<<11)-1L);
if(exp == 0)
return snprint(buf, n, "DeN(%.8lux%.8lux)", h, l);
if(exp == ((1L<<11)-1L)){
if(l==0 && (h&((1L<<20)-1L)) == 0)
return snprint(buf, n, "Inf");
else
return snprint(buf, n, "NaN(%.8lux%.8lux)", h&((1L<<20)-1L), l);
}
exp -= (1L<<10) - 2L;
fr = l & ((1L<<16)-1L);
fr /= 1L<<16;
fr += (l>>16) & ((1L<<16)-1L);
fr /= 1L<<16;
fr += (h & (1L<<20)-1L) | (1L<<20);
fr /= 1L<<21;
fr = ldexp(fr, exp);
return snprint(buf, n, "%.18g", fr);
}
int
ieeeftoa32(char *buf, uint n, u32int h)
{
double fr;
int exp;
if (n <= 0)
return 0;
if(h & (1UL<<31)){
*buf++ = '-';
h &= ~(1UL<<31);
}else
*buf++ = ' ';
n--;
if(h == 0)
return snprint(buf, n, "0.");
exp = (h>>23) & ((1L<<8)-1L);
if(exp == 0)
return snprint(buf, n, "DeN(%.8lux)", h);
if(exp == ((1L<<8)-1L)){
if((h&((1L<<23)-1L)) == 0)
return snprint(buf, n, "Inf");
else
return snprint(buf, n, "NaN(%.8lux)", h&((1L<<23)-1L));
}
exp -= (1L<<7) - 2L;
fr = (h & ((1L<<23)-1L)) | (1L<<23);
fr /= 1L<<24;
fr = ldexp(fr, exp);
return snprint(buf, n, "%.9g", fr);
}
int
beieeeftoa32(char *buf, uint n, void *s)
{
return ieeeftoa32(buf, n, beswap4(*(u32int*)s));
}
int
beieeeftoa64(char *buf, uint n, void *s)
{
return ieeeftoa64(buf, n, beswap4(*(u32int*)s), beswap4(((u32int*)(s))[1]));
}
int
leieeeftoa32(char *buf, uint n, void *s)
{
return ieeeftoa32(buf, n, leswap4(*(u32int*)s));
}
int
leieeeftoa64(char *buf, uint n, void *s)
{
return ieeeftoa64(buf, n, leswap4(((u32int*)(s))[1]), leswap4(*(u32int*)s));
}
/* packed in 12 bytes, with s[2]==s[3]==0; mantissa starts at s[4]*/
int
beieeeftoa80(char *buf, uint n, void *s)
{
uchar *reg = (uchar*)s;
int i;
ulong x;
uchar ieee[8+8]; /* room for slop */
uchar *p, *q;
memset(ieee, 0, sizeof(ieee));
/* sign */
if(reg[0] & 0x80)
ieee[0] |= 0x80;
/* exponent */
x = ((reg[0]&0x7F)<<8) | reg[1];
if(x == 0) /* number is ±0 */
goto done;
if(x == 0x7FFF){
if(memcmp(reg+4, ieee+1, 8) == 0){ /* infinity */
x = 2047;
}else{ /* NaN */
x = 2047;
ieee[7] = 0x1; /* make sure */
}
ieee[0] |= x>>4;
ieee[1] |= (x&0xF)<<4;
goto done;
}
x -= 0x3FFF; /* exponent bias */
x += 1023;
if(x >= (1<<11) || ((reg[4]&0x80)==0 && x!=0))
return snprint(buf, n, "not in range");
ieee[0] |= x>>4;
ieee[1] |= (x&0xF)<<4;
/* mantissa */
p = reg+4;
q = ieee+1;
for(i=0; i<56; i+=8, p++, q++){ /* move one byte */
x = (p[0]&0x7F) << 1;
if(p[1] & 0x80)
x |= 1;
q[0] |= x>>4;
q[1] |= (x&0xF)<<4;
}
done:
return beieeeftoa64(buf, n, (void*)ieee);
}
int
leieeeftoa80(char *buf, uint n, void *s)
{
int i;
char *cp;
char b[12];
cp = (char*) s;
for(i=0; i<12; i++)
b[11-i] = *cp++;
return beieeeftoa80(buf, n, b);
}
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