diff options
Diffstat (limited to 'src/floatfns.c')
| -rw-r--r-- | src/floatfns.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/src/floatfns.c b/src/floatfns.c index a626845377a..30526a16443 100644 --- a/src/floatfns.c +++ b/src/floatfns.c @@ -340,9 +340,8 @@ This is the same as the exponent of a float. */) representable as a double. Return DBL_MANT_DIG - DBL_MIN_EXP (the maximum possible valid - scale) if D is zero or tiny. Return a value greater than - DBL_MANT_DIG - DBL_MIN_EXP if there is conversion trouble; on all - current platforms this can happen only if D is infinite or a NaN. */ + scale) if D is zero or tiny. Return one greater than that if + D is infinite, and two greater than that if D is a NaN. */ int double_integer_scale (double d) @@ -351,11 +350,10 @@ double_integer_scale (double d) return (DBL_MIN_EXP - 1 <= exponent && exponent < INT_MAX ? DBL_MANT_DIG - 1 - exponent : (DBL_MANT_DIG - DBL_MIN_EXP - + (exponent == INT_MAX - || (exponent == FP_ILOGBNAN - && (FP_ILOGBNAN != FP_ILOGB0 || isnan (d))) - || (!IEEE_FLOATING_POINT && exponent == INT_MIN - && (FP_ILOGB0 != INT_MIN || d != 0))))); + + ((exponent == FP_ILOGBNAN + && (FP_ILOGBNAN != FP_ILOGB0 || isnan (d))) + ? 2 + : exponent == INT_MAX))); } /* Convert the Lisp number N to an integer and return a pointer to the @@ -404,6 +402,7 @@ rounding_driver (Lisp_Object n, Lisp_Object d, CHECK_NUMBER (d); + int dscale = 0; if (FIXNUMP (d)) { if (XFIXNUM (d) == 0) @@ -413,9 +412,21 @@ rounding_driver (Lisp_Object n, Lisp_Object d, if (FIXNUMP (n)) return make_int (fixnum_divide (XFIXNUM (n), XFIXNUM (d))); } + else if (FLOATP (d)) + { + if (XFLOAT_DATA (d) == 0) + xsignal0 (Qarith_error); + dscale = double_integer_scale (XFLOAT_DATA (d)); + } int nscale = FLOATP (n) ? double_integer_scale (XFLOAT_DATA (n)) : 0; - int dscale = FLOATP (d) ? double_integer_scale (XFLOAT_DATA (d)) : 0; + + /* If the numerator is finite and the denominator infinite, the + quotient is zero and there is no need to try the impossible task + of rescaling the denominator. */ + if (dscale == DBL_MANT_DIG - DBL_MIN_EXP + 1 && nscale < dscale) + return make_fixnum (0); + int_divide (mpz[0], *rescale_for_division (n, &mpz[0], nscale, dscale), *rescale_for_division (d, &mpz[1], dscale, nscale)); |