diff options
Diffstat (limited to 'tests/tsub1sp.c')
| -rw-r--r-- | tests/tsub1sp.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/tests/tsub1sp.c b/tests/tsub1sp.c index 5a6be30d5..adc4e3aef 100644 --- a/tests/tsub1sp.c +++ b/tests/tsub1sp.c @@ -284,6 +284,91 @@ bug20171213_gen (mpfr_prec_t pmax) } } +static void +coverage (void) +{ + mpfr_t a, b, c, d, u; + int inex; + + /* coverage test in mpfr_sub1sp: case d=1, limb > MPFR_LIMB_HIGHBIT, RNDF + and also RNDZ */ + mpfr_init2 (a, 3 * GMP_NUMB_BITS); + mpfr_init2 (b, 3 * GMP_NUMB_BITS); + mpfr_init2 (c, 3 * GMP_NUMB_BITS); + mpfr_init2 (d, 3 * GMP_NUMB_BITS); + mpfr_init2 (u, 3 * GMP_NUMB_BITS); + mpfr_set_ui (b, 1, MPFR_RNDN); + mpfr_nextbelow (b); /* b = 1 - 2^(-p) */ + mpfr_set_prec (c, GMP_NUMB_BITS); + mpfr_set_ui_2exp (c, 1, -1, MPFR_RNDN); + mpfr_nextbelow (c); + mpfr_nextbelow (c); /* c = 1/2 - 2*2^(-GMP_NUMB_BITS-1) */ + mpfr_prec_round (c, 3 * GMP_NUMB_BITS, MPFR_RNDN); + mpfr_nextbelow (c); /* c = 1/2 - 2*2^(-GMP_NUMB_BITS-1) - 2^(-p-1) */ + /* b-c = c */ + mpfr_sub (a, b, c, MPFR_RNDF); + mpfr_sub (d, b, c, MPFR_RNDD); + mpfr_sub (u, b, c, MPFR_RNDU); + /* check a = d or u */ + MPFR_ASSERTN(mpfr_equal_p (a, d) || mpfr_equal_p (a, u)); + + /* coverage test in mpfr_sub1sp: case d=p, RNDN, sb = 0, significand of b + is even but b<>2^e, (case 1e) */ + mpfr_set_prec (a, 3 * GMP_NUMB_BITS); + mpfr_set_prec (b, 3 * GMP_NUMB_BITS); + mpfr_set_prec (c, 3 * GMP_NUMB_BITS); + mpfr_set_ui (b, 1, MPFR_RNDN); + mpfr_nextabove (b); + mpfr_nextabove (b); + mpfr_set_ui_2exp (c, 1, -3 * GMP_NUMB_BITS, MPFR_RNDN); + inex = mpfr_sub (a, b, c, MPFR_RNDN); + MPFR_ASSERTN(inex > 0); + MPFR_ASSERTN(mpfr_equal_p (a, b)); + + mpfr_clear (a); + mpfr_clear (b); + mpfr_clear (c); + mpfr_clear (d); + mpfr_clear (u); +} + +/* bug in mpfr_sub1sp1n, made generic */ +static void +bug20180217 (mpfr_prec_t pmax) +{ + mpfr_t a, b, c; + int inex; + mpfr_prec_t p; + + for (p = MPFR_PREC_MIN; p <= pmax; p++) + { + mpfr_init2 (a, p); + mpfr_init2 (b, p); + mpfr_init2 (c, p); + mpfr_set_ui (b, 1, MPFR_RNDN); /* b = 1 */ + mpfr_set_ui_2exp (c, 1, -p-1, MPFR_RNDN); /* c = 2^(-p-1) */ + /* a - b = 1 - 2^(-p-1) and should be rounded to 1 (case 2f of + mpfr_sub1sp) */ + inex = mpfr_sub (a, b, c, MPFR_RNDN); + MPFR_ASSERTN(inex > 0); + MPFR_ASSERTN(mpfr_cmp_ui (a, 1) == 0); + /* check also when a=b */ + mpfr_set_ui (a, 1, MPFR_RNDN); + inex = mpfr_sub (a, a, c, MPFR_RNDN); + MPFR_ASSERTN(inex > 0); + MPFR_ASSERTN(mpfr_cmp_ui (a, 1) == 0); + /* and when a=c */ + mpfr_set_ui (b, 1, MPFR_RNDN); /* b = 1 */ + mpfr_set_ui_2exp (a, 1, -p-1, MPFR_RNDN); + inex = mpfr_sub (a, b, a, MPFR_RNDN); + MPFR_ASSERTN(inex > 0); + MPFR_ASSERTN(mpfr_cmp_ui (a, 1) == 0); + mpfr_clear (a); + mpfr_clear (b); + mpfr_clear (c); + } +} + int main (void) { @@ -291,6 +376,8 @@ main (void) tests_start_mpfr (); + bug20180217 (1024); + coverage (); compare_sub_sub1sp (); test20170208 (); bug20170109 (); |