import/export of exact mp floating constants

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

diff --git a/src/cmd/gc/export.c b/src/cmd/gc/export.c
index 66a568cc4a98c926ef4db48610ec6b31ce1e064e..3d7984bd8e9ad3ed0ca2eca7628ac3989579fe06 100644 (file)
--- a/src/cmd/gc/export.c
+++ b/src/cmd/gc/export.c
@@ -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);

diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 2654e1c564b881589b82fd8c3ac19c917226515d..ea5321f529f905d7cdfa00ea756fbbb1a04e77f1 100644 (file)
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -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

diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index f818a641fa00e229cbe096bff1e5a92a36579efe..126a201d6f16b110cbf895bae18792db3c35df98 100644 (file)
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -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;

diff --git a/src/cmd/gc/mparith1.c b/src/cmd/gc/mparith1.c
index 2bf20d60eee8de6ee730b3f25a3f62548fd011bd..1fd8d7f0fe4ab7b467149e96ac4455b37c7bd1d8 100644 (file)
--- a/src/cmd/gc/mparith1.c
+++ b/src/cmd/gc/mparith1.c
@@ -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;
+
+       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;
+       }
 
-       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);
+       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);
 }