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import/export of exact mp floating constants

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new syntax for exact mp floating constants
     decimal_int ( "p" | "P" ) [ "+" | "-" ] decimal_int
     the value is decimal1 * 2^decimal2

R=r
OCL=20357
CL=20357
This commit is contained in:
Ken Thompson 2008-12-03 13:17:26 -08:00
parent 98431dbfff
commit f8797daa9f
4 changed files with 60 additions and 9 deletions
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2
src/cmd/gc/export.c
View File

@ -105,7 +105,7 @@ dumpexportconst(Sym *s)
Bprint(bout, "0x%llux\n", n->val.u.bval);
break;
case CTFLT:
Bprint(bout, "%.17e\n", mpgetflt(n->val.u.fval));
Bprint(bout, "%F\n", n->val.u.fval);
break;
case CTSTR:
Bprint(bout, "\"%Z\"\n", n->val.u.sval);

3
src/cmd/gc/go.h
View File

@ -567,6 +567,8 @@ void mpshiftfix(Mpint *a, int s);
/*
* mparith3.c
*/
int sigfig(Mpflt *a);
void mpnorm(Mpflt *a);
void mpmovefltflt(Mpflt *a, Mpflt *b);
void mpmovecflt(Mpflt *a, double f);
int mptestflt(Mpflt *a);
@ -576,7 +578,6 @@ void mpdivfltflt(Mpflt *a, Mpflt *b);
void mpnegflt(Mpflt *a);
double mpgetflt(Mpflt *a);
int Fconv(Fmt*);
void mpnorm(Mpflt *a);
/*
* subr.c

18
src/cmd/gc/lex.c
View File

@ -742,6 +742,8 @@ dc:
goto casedot;
if(c == 'e' || c == 'E')
goto casee;
if(c == 'p' || c == 'P')
goto casep;
ncu:
*cp = 0;
@ -780,6 +782,22 @@ casee:
*cp++ = c;
c = getc();
}
goto caseout;
casep:
*cp++ = 'p';
c = getc();
if(c == '+' || c == '-') {
*cp++ = c;
c = getc();
}
if(!isdigit(c))
yyerror("malformed fp constant exponent");
while(isdigit(c)) {
*cp++ = c;
c = getc();
}
goto caseout;
caseout:
*cp = 0;

46
src/cmd/gc/mparith1.c
View File

@ -194,13 +194,14 @@ void
mpatoflt(Mpflt *a, char *as)
{
Mpflt b;
int dp, c, f, ef, ex, zer;
int dp, c, f, ef, ex, eb, zer;
char *s;
s = as;
dp = 0; /* digits after decimal point */
f = 0; /* sign */
ex = 0; /* exponent */
eb = 0; /* binary point */
zer = 1; /* zero */
mpmovecflt(a, 0.0);
@ -239,6 +240,10 @@ mpatoflt(Mpflt *a, char *as)
dp++;
continue;
case 'P':
case 'p':
eb = 1;
case 'E':
case 'e':
ex = 0;
@ -266,6 +271,13 @@ mpatoflt(Mpflt *a, char *as)
break;
}
if(eb) {
if(dp)
goto bad;
a->exp += ex;
goto out;
}
if(dp)
dp--;
if(mpcmpfltc(a, 0.0) != 0) {
@ -277,6 +289,8 @@ mpatoflt(Mpflt *a, char *as)
mpdivfltflt(a, &b);
}
}
out:
if(f)
mpnegflt(a);
return;
@ -407,12 +421,30 @@ int
Fconv(Fmt *fp)
{
char buf[500];
Mpflt *fval;
Mpflt *fvp, fv;
fval = va_arg(fp->args, Mpflt*);
if(fval->exp >= 0)
snprint(buf, sizeof(buf), "(%B*2^%d)", &fval->val, fval->exp);
else
snprint(buf, sizeof(buf), "(%B/2^%d)", &fval->val, -fval->exp);
fvp = va_arg(fp->args, Mpflt*);
if(sigfig(fvp) == 0) {
snprint(buf, sizeof(buf), "0p+0");
goto out;
}
fv = *fvp;
while(fv.val.a[0] == 0) {
mpshiftfix(&fv.val, -Mpscale);
fv.exp += Mpscale;
}
while((fv.val.a[0]&1) == 0) {
mpshiftfix(&fv.val, -1);
fv.exp += 1;
}
if(fv.exp >= 0) {
snprint(buf, sizeof(buf), "%Bp+%d", &fv.val, fv.exp);
goto out;
}
snprint(buf, sizeof(buf), "%Bp-%d", &fv.val, -fv.exp);
out:
return fmtstrcpy(fp, buf);
}