diff options
Diffstat (limited to 'Objects/longobject.c')
| -rw-r--r-- | Objects/longobject.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c index badc3df..de7ff39 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -28,8 +28,14 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. #include "allobjects.h" #include "longintrepr.h" +#include <math.h> #include <assert.h> +/* Forward: */ +extern object *long_mul PROTO((longobject *, object *)); +extern object *long_add PROTO((longobject *, object *)); +extern object *long_neg PROTO((longobject *)); + static int ticker; /* XXX Could be shared with ceval? */ #define INTRCHECK(block) \ @@ -87,6 +93,39 @@ newlongobject(ival) return (object *)v; } +/* Create a new long int object from a C double */ + +object * +dnewlongobject(dval) + double dval; +{ + longobject *v; + double frac; + int i, ndig, expo, neg; + neg = 0; + if (dval < 0.0) { + neg = 1; + dval = -dval; + } + frac = frexp(dval, &expo); /* dval = frac*2**expo; 0.0 <= frac < 1.0 */ + if (expo <= 0) + return newlongobject(0L); + ndig = (expo-1) / SHIFT + 1; /* Number of 'digits' in result */ + v = alloclongobject(ndig); + if (v == NULL) + return NULL; + frac = ldexp(frac, (expo-1) % SHIFT + 1); + for (i = ndig; --i >= 0; ) { + long bits = (long)frac; + v->ob_digit[i] = bits; + frac = frac - (double)bits; + frac = ldexp(frac, SHIFT); + } + if (neg) + v->ob_size = -v->ob_size; + return (object *)v; +} + /* Get a C long int from a long int object. Returns -1 and sets an error condition if overflow occurs. */ |