diff options
Diffstat (limited to 'src/get_sj.c')
| -rw-r--r-- | src/get_sj.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/src/get_sj.c b/src/get_sj.c index 5e92199d0..f270f375c 100644 --- a/src/get_sj.c +++ b/src/get_sj.c @@ -35,6 +35,7 @@ mpfr_get_sj (mpfr_srcptr f, mpfr_rnd_t rnd) intmax_t r; mpfr_prec_t prec; mpfr_t x; + MPFR_SAVE_EXPO_DECL (expo); if (MPFR_UNLIKELY (!mpfr_fits_intmax_p (f, rnd))) { @@ -46,20 +47,24 @@ mpfr_get_sj (mpfr_srcptr f, mpfr_rnd_t rnd) if (MPFR_IS_ZERO (f)) return (intmax_t) 0; - /* determine the precision of intmax_t */ - for (r = MPFR_INTMAX_MIN, prec = 0; r != 0; r /= 2, prec++) + /* Determine the precision of intmax_t. |INTMAX_MIN| may have one + more bit as an integer, but in this case, this is a power of 2, + thus fits in a precision-prec floating-point number. */ + for (r = MPFR_INTMAX_MAX, prec = 0; r != 0; r /= 2, prec++) { } - /* Note: though INTMAX_MAX would have been sufficient for the conversion, - we chose INTMAX_MIN so that INTMAX_MIN - 1 is always representable in - precision prec; this is useful to detect overflows in MPFR_RNDZ (will - be needed later). */ - /* Now, r = 0. */ + MPFR_ASSERTD (r == 0); + + MPFR_SAVE_EXPO_MARK (expo); mpfr_init2 (x, prec); mpfr_rint (x, f, rnd); MPFR_ASSERTN (MPFR_IS_FP (x)); + /* The flags from mpfr_rint are the wanted ones. In particular, + it sets the inexact flag when necessary. */ + MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags); + if (MPFR_NOTZERO (x)) { mp_limb_t *xp; @@ -67,15 +72,15 @@ mpfr_get_sj (mpfr_srcptr f, mpfr_rnd_t rnd) xp = MPFR_MANT (x); sh = MPFR_GET_EXP (x); - MPFR_ASSERTN ((mpfr_prec_t) sh <= prec); + MPFR_ASSERTN ((mpfr_prec_t) sh <= prec + 1); if (MPFR_INTMAX_MIN + MPFR_INTMAX_MAX != 0 - && MPFR_UNLIKELY ((mpfr_prec_t) sh == prec)) + && MPFR_UNLIKELY ((mpfr_prec_t) sh > prec)) { /* 2's complement and x <= INTMAX_MIN: in the case mp_limb_t has the same size as intmax_t, we cannot use the code in the for loop since the operations would be performed in unsigned arithmetic. */ - MPFR_ASSERTN (MPFR_IS_NEG (x) && (mpfr_powerof2_raw (x))); + MPFR_ASSERTN (MPFR_IS_NEG (x) && mpfr_powerof2_raw (x)); r = MPFR_INTMAX_MIN; } else if (MPFR_IS_POS (x)) @@ -117,6 +122,8 @@ mpfr_get_sj (mpfr_srcptr f, mpfr_rnd_t rnd) mpfr_clear (x); + MPFR_SAVE_EXPO_FREE (expo); + return r; } |