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[Gbhardplate-misc] Les flottants sur gbdk
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From: Fabien P. <fab...@re...> - 2002-05-22 14:43:31
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Bonjour,
Voil=E0 une premi=E8re version de librairie flottante pour le gbdk, =E9vi=
demment elle est bugg=E9e, mais je pense qu'en testant les fonctions une =
par une, il doit =EAtre possible de valider et d=E9bugguer chaque
fonction.
Sont not=E9es //FAP les modifs par rapport =E0 la version d'origine sdcc =
o=F9 j'ai piqu=E9 le code pour que gbdk puisse compiler.
//ok c'est quand j'ai test=E9 et que pour moi c'est bon.
Avis aux amateurs, pour d=E9bugguer, tester, je suis =E0 votre dispositio=
n pour toute question sur ce code.
Il faudrait valider que les calculs sur les long sont valides, sinon on a=
urait plus vite fait de tout r=E9=E9crire de 0.
A+
Fabien
le code :
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#include <stdio.h>
/* the following deal with IEEE single-precision numbers */
#define EXCESS 126
#define SIGNBIT ((unsigned long)0x80000000)
#define HIDDEN (unsigned long)(1 << 23)
#define SIGN(fp) ((fp >> (8*sizeof(fp)-1)) & 1)
#define EXP(fp) (((fp) >> 23) & (unsigned int) 0x00FF)
#define MANT(fp) (((fp) & (unsigned long)0x007FFFFF) | HIDDEN)
#define PACK(s,e,m) ((s) | ((e) << 23) | (m))
#define ULONG_MAX 0xffffffff
#define DEFAULT_FLOAT_PRECISION 6
union float_long {
float f;
long l;
};
char output_ptr[150] ;
static int charsOutputted =3D 0;
static void output_char( char c )
{
output_ptr[charsOutputted++] =3D c;
}
// compare two floats // lower than <=3D //FAP
char fslt (float a1, float a2)
{
volatile union float_long fl1, fl2;
fl1.f =3D a1;
fl2.f =3D a2;
if (SIGN (fl1.l) && SIGN (fl2.l))
{
fl1.l ^=3D SIGNBIT;
fl2.l ^=3D SIGNBIT;
}
if (fl1.l < fl2.l)
return (1);
return (0);
}
/* convert float to unsigned long */
unsigned long fs2ulong (float a1)
{
volatile union float_long fl1;
volatile int exp;
volatile long l;
fl1.f =3D a1;
if (!fl1.l || SIGN(fl1.l))
return (0);
if (fslt(ULONG_MAX,a1))
return ULONG_MAX;
exp =3D EXP (fl1.l) - EXCESS - 24;
l =3D MANT (fl1.l);
l >>=3D -exp;
return l;
}
/* add two floats */
float fsadd (float a1, float a2)
{
volatile long mant1, mant2;
volatile union float_long fl1, fl2;
volatile int exp1, exp2;
volatile long sign =3D 0;
fl1.f =3D a1;
fl2.f =3D a2;
/* check for zero args */
if (!fl1.l)
return (fl2.f);
if (!fl2.l)
return (fl1.f);
exp1 =3D EXP (fl1.l);
exp2 =3D EXP (fl2.l);
if (exp1 > exp2 + 25)
return (fl1.f); // return (fl1.l); //FAP
if (exp2 > exp1 + 25)
return (fl2.f); // return (fl2.l); //FAP
/* do everything in excess precision so's we can round later */
mant1 =3D MANT (fl1.l) << 6;
mant2 =3D MANT (fl2.l) << 6;
if (SIGN (fl1.l))
mant1 =3D -mant1;
if (SIGN (fl2.l))
mant2 =3D -mant2;
if (exp1 > exp2)
{
mant2 >>=3D exp1 - exp2;
}
else
{
mant1 >>=3D exp2 - exp1;
exp1 =3D exp2;
}
mant1 +=3D mant2;
if (mant1 < 0)
{
mant1 =3D -mant1;
sign =3D SIGNBIT;
}
else if (!mant1)
return (0);
/* normalize up */
while (!(mant1 & (unsigned long) 0xE0000000))
{
mant1 <<=3D 1;
exp1--;
}
/* normalize down? */
if (mant1 & (unsigned long)(1 << 30))
{
mant1 >>=3D 1 ;
exp1++;
}
/* round to even */
mant1 +=3D (mant1 & (unsigned long)0x40) ? (unsigned long) 0x20 : (unsi=
gned long) 0x1F;
/* normalize down? */
if (mant1 & (unsigned long)(1 << 30))
{
mant1 >>=3D 1;
exp1++;
}
/* lose extra precision */
mant1 >>=3D 6;
/* turn off hidden bit */
mant1 &=3D ~HIDDEN;
/* pack up and go home */
fl1.l =3D PACK (sign, (unsigned long) exp1, mant1);
return (fl1.f);
}
/* subtract two floats */
float fssub (float a1, float a2)
{
volatile union float_long fl1, fl2;
fl1.f =3D a1;
fl2.f =3D a2;
/* check for zero args */
if (!fl2.l)
return (fl1.f);
if (!fl1.l) {
//return (-fl2.f); //FAP
fl2.l ^=3D SIGNBIT; //FAP
return (fl2.f); //FAP
}
/* twiddle sign bit and add */
fl2.l ^=3D SIGNBIT;
return fsadd(fl1.f, fl2.f); //return fl1.f + fl2.f;//FAP
}
float ulong2fs (unsigned long a )
{
int exp =3D 24 + EXCESS;
volatile union float_long fl;
if (!a)
{
return 0.0;
}
while (a < HIDDEN)
{
a <<=3D 1;
exp--;
}
a &=3D ~HIDDEN ;
/* pack up and go home */
fl.l =3D PACK(0,(unsigned long)exp, a);
return (fl.f);
}
/* convert signed long to float */
float slong2fs (signed long sl) {
volatile union float_long fl;
if (sl<0) {
// return -ulong2fs(-sl); //FAP
fl.f =3D ulong2fs(-sl);//FAP
fl.l ^=3D SIGNBIT;//FAP
return fl.f;//FAP
}
else
return ulong2fs(sl);
}
/* multiply two floats */
float fsmul (float a1, float a2)
{
volatile union float_long fl1, fl2;
volatile unsigned long result;
volatile int exp;
char sign;
fl1.f =3D a1;
fl2.f =3D a2;
if (!fl1.l || !fl2.l)
return (0);
/* compute sign and exponent */
sign =3D SIGN (fl1.l) ^ SIGN (fl2.l);
exp =3D EXP (fl1.l) - EXCESS;
exp +=3D EXP (fl2.l);
fl1.l =3D MANT (fl1.l);
fl2.l =3D MANT (fl2.l);
/* the multiply is done as one 16x16 multiply and two 16x8 multiples */=
result =3D (fl1.l >> 8) * (fl2.l >> 8);
result +=3D ((fl1.l & (unsigned long) 0xFF) * (fl2.l >> 8)) >> 8;
result +=3D ((fl2.l & (unsigned long) 0xFF) * (fl1.l >> 8)) >> 8;
if (result & (unsigned long)0x80000000)
{
/* round */
result +=3D 0x80;
result >>=3D 8;
}
else
{
/* round */
result +=3D 0x40;
result >>=3D 7;
exp--;
}
result &=3D ~HIDDEN;
/* pack up and go home */
fl1.l =3D PACK (sign ? ((unsigned long) 0x80000000) : 0 , (unsigned lon=
g)exp, result);
return (fl1.f);
}
static void output_float (float f, unsigned char reqWidth,
signed char reqDecimals,
unsigned char left, unsigned char zero, unsigned char sign, unsigned=
char space)
{
unsigned char minWidth, i;
char negative=3D0;
long integerPart;
float decimalPart;
char fpBuffer[128];
char fpBI=3D0, fpBD;
volatile union float_long tmp;
tmp.f =3D f;
// save the sign
if (SIGN (tmp.l)) { // if (f<0) { //FAP
negative=3D1;
tmp.l ^=3D SIGNBIT; // f=3D-f; //FAP
}
// split the float
integerPart =3D fs2ulong(tmp.f);// integerPart =3D f; //FAP
decimalPart =3D fssub(tmp.f, slong2fs(integerPart)); // decimalPart =3D=
tmp.f - integerPart; //FAP
// fill the buffer with the integerPart (in reversed order!)
while (integerPart) {
char i =3D integerPart%10;
fpBuffer[fpBI++]=3D'0' + integerPart%10;
integerPart /=3D 10;
}
if (!fpBI) {
// we need at least a 0
fpBuffer[fpBI++]=3D'0';
}
// display some decimals as default
if (reqDecimals=3D=3D-1)
reqDecimals=3DDEFAULT_FLOAT_PRECISION;
// fill buffer with the decimalPart (in normal order)
fpBD=3DfpBI;
if (i=3DreqDecimals ) { // that's an assignment
do {
decimalPart =3D fsmul(decimalPart, 10.0);//decimalPart *=3D 10.0; /=
/FAP
// truncate the float
integerPart=3Dfs2ulong(decimalPart); // integerPart=3DdecimalPart; =
//FAP
fpBuffer[fpBD++]=3D'0' + integerPart;
decimalPart=3Dfssub(decimalPart,ulong2fs(integerPart)); //decimalPa=
rt-=3DintegerPart; //FAP
} while (--i);
}
minWidth=3DfpBI; // we need at least these
minWidth+=3DreqDecimals?reqDecimals+1:0; // maybe these
if (negative || sign || space)
minWidth++; // and maybe even this :)
if (!left && reqWidth>i) {
if (zero) {
if (negative) output_char('-');
else if (sign) output_char('+');
else if (space) output_char(' ');
while (reqWidth-->minWidth)
output_char ('0');
} else {
while (reqWidth-->minWidth)
output_char (' ');
if (negative) output_char('-');
else if (sign) output_char('+');
else if (space) output_char (' ');
}
} else {
if (negative) output_char('-');
else if (sign) output_char('+');
else if (space) output_char(' ');
}
// output the integer part
i=3DfpBI-1;
do {
output_char (fpBuffer[i]);
} while (i--);
// ouput the decimal part
if (reqDecimals) {
output_char ('.');
i=3DfpBI;
while (reqDecimals--)
output_char (fpBuffer[i++]);
}
if (left && reqWidth>minWidth) {
while (reqWidth-->minWidth)
output_char(' ');
}
output_char(0);
charsOutputted =3D 0;
}
// compare two floats // greater than >=3D //FAP
char fsgt (float a1, float a2)
{
volatile union float_long fl1, fl2;
fl1.f =3D a1;
fl2.f =3D a2;
if (SIGN (fl1.l) && SIGN (fl2.l))
{
fl1.l ^=3D SIGNBIT;
fl2.l ^=3D SIGNBIT;
}
if (fl1.l > fl2.l)
return (1);
return (0);
}
/* compare two floats */
char fsneq (float a1, float a2)
{
volatile union float_long fl1, fl2;
fl1.f =3D a1;
fl2.f =3D a2;
if (SIGN (fl1.l) && SIGN (fl2.l))
{
fl1.l ^=3D SIGNBIT;
fl2.l ^=3D SIGNBIT;
}
if (fl1.l =3D=3D fl2.l)
return (0);
return (1);
}
/* compare two floats */
char fseq (float a1, float a2) //ok
{
volatile union float_long fl1, fl2;
fl1.f =3D a1;
fl2.f =3D a2;
if (SIGN (fl1.l) && SIGN (fl2.l))
{
fl1.l ^=3D SIGNBIT;
fl2.l ^=3D SIGNBIT;
}
if (fl1.l =3D=3D fl2.l)
return (1);
return (0);
}
void main()
{
float a =3D -0.03; //ok
float b =3D 0.02; //ok
float c;
c =3D fsadd(a,b);
if (fsgt(-0.03, -0.02))
printf("ok\n");
output_float (a, 0, -1, 0, 0, 1, 1);
printf("%s\n", output_ptr);
output_float (b, 0, -1, 0, 0, 1, 1);
printf("%s\n", output_ptr);
output_float (c, 0, -1, 0, 0, 1, 1);
printf("%s\n", output_ptr);
}
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le makefile.bat
-------------------------------------------------
=2E.\..\bin\lcc -Wa-l -Wl-m -Wl-j -c -o float_gbdk.o float_gbdk.c
=2E.\..\bin\lcc -Wa-l -Wl-m -Wl-j -o float_gbdk.gb float_gbdk.o
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