When converting doubles to bignums fill up 3 digits. Pass test 60 on 32bit machines

Author: pmurias

src/ops/nqp_bigint.ops

@@ -54,26 +54,38 @@ static void from_num(FLOATVAL d, mp_int *a) {
     FLOATVAL da      = fabs(d);
     FLOATVAL upper;
     FLOATVAL lower;
+    FLOATVAL lowest;
+    FLOATVAL rest;
     int      digits  = 0;
 
     mp_zero(a);
 
-    while (da > d_digit * d_digit) {;
+    while (da > d_digit * d_digit * d_digit) {;
         da /= d_digit;
         digits++;
     }
-    mp_grow(a, digits + 2);
+    mp_grow(a, digits + 3);
 
-    /* populate the top 2 digits */
-    upper = da / d_digit;
-    lower = fmod(da, d_digit);
+    /* populate the top 3 digits */
+    upper = da / (d_digit*d_digit);
+    rest = fmod(da, d_digit*d_digit);
+    lower = rest / d_digit;
+    lowest = fmod(rest,d_digit );
     if (upper >= 1) {
         mp_set_long(a, (unsigned long) upper);
         mp_mul_2d(a, DIGIT_BIT , a);
+        DIGIT(a, 0) = (mp_digit) lower;
+        mp_mul_2d(a, DIGIT_BIT , a);
     } else {
-        a->used = 1;
+        if (lower >= 1) {
+            mp_set_long(a, (unsigned long) lower);
+            mp_mul_2d(a, DIGIT_BIT , a);
+            a->used = 2;
+        } else {
+            a->used = 1;
+        }
     }
-    DIGIT(a, 0) = (mp_digit) lower;
+    DIGIT(a, 0) = (mp_digit) lowest;
 
     /* shift the rest */
     mp_mul_2d(a, DIGIT_BIT * digits, a);

t/nqp/60-bigint.t

@@ -1,7 +1,7 @@
 #! nqp
 use nqpmo;
 
-plan(34);
+plan(36);
 
 my $knowhow := pir::get_knowhow__P();
 my $bi_type := $knowhow.new_type(:name('TestBigInt'), :repr('P6bigint'));
@@ -80,6 +80,12 @@ ok(nqp::abs_n($big - $converted) / $big < 1e-4, 'bigint -> float, 1e16');
 my $float := 123456789e240;
 ok(nqp::iseq_n($float, nqp::tonum_I(nqp::fromnum_I($float, $bi_type))),
     'to_num and from_num round-trip');
+my $small_float := 1e3;
+ok(nqp::iseq_n($small_float, nqp::tonum_I(nqp::fromnum_I($small_float, $bi_type))),
+    'to_num and from_num round-trip on small floats');
+my $medium_float := 1e14;
+ok(nqp::iseq_n($medium_float, nqp::tonum_I(nqp::fromnum_I($medium_float, $bi_type))),
+    'to_num and from_num round-trip on medium sized floats');
 $float := -$float;
 ok(nqp::iseq_n($float, nqp::tonum_I(nqp::fromnum_I($float, $bi_type))),
     'to_num and from_num round-trip (negative number)');