1 files changed, 47 insertions, 15 deletions

diff --git a/mpfr.c b/mpfr.c
index 52247978..758adfb1 100644
--- a/mpfr.c
+++ b/mpfr.c
@@ -697,22 +697,35 @@ do_mpfr_atan2(int nargs)
 	return res;
 }
 
+/* do_mpfr_func --- run an MPFR function - not inline, for debugging */
 
-#define SPEC_MATH(X)						\
-NODE *t1, *res;							\
-mpfr_ptr p1;							\
-int tval;							\
-t1 = POP_SCALAR();						\
-if (do_lint && (t1->flags & (NUMCUR|NUMBER)) == 0)		\
-	lintwarn(_("%s: received non-numeric argument"), #X);	\
-force_number(t1);						\
-p1 = MP_FLOAT(t1);						\
-res = mpg_float();						\
-tval = mpfr_##X(res->mpg_numbr, p1, ROUND_MODE);			\
-IEEE_FMT(res->mpg_numbr, tval);					\
-DEREF(t1);							\
-return res
+static inline NODE *
+do_mpfr_func(const char *name,
+		int (*mpfr_func)(),	/* putting argument types just gets the compiler confused */
+		int nargs)
+{
+	NODE *t1, *res;
+	mpfr_ptr p1;
+	int tval;
+
+	t1 = POP_SCALAR();
+	if (do_lint && (t1->flags & (NUMCUR|NUMBER)) == 0)
+		lintwarn(_("%s: received non-numeric argument"), name);
+
+	force_number(t1);
+	p1 = MP_FLOAT(t1);
+	res = mpg_float();
+	mpfr_set_prec(res->mpg_numbr, mpfr_get_prec(p1));	/* needed at least for sqrt() */
+	tval = mpfr_func(res->mpg_numbr, p1, ROUND_MODE);
+	IEEE_FMT(res->mpg_numbr, tval);
+	DEREF(t1);
+	return res;
+}
 
+#define SPEC_MATH(X)				\
+NODE *result;					\
+result = do_mpfr_func(#X, mpfr_##X, nargs);	\
+return result
 
 /* do_mpfr_sin --- do the sin function */
 
@@ -1452,8 +1465,27 @@ mpg_mod(NODE *t1, NODE *t2)
 	int tval;
 
 	if (is_mpg_integer(t1) && is_mpg_integer(t2)) {
+		/*
+		 * 8/2014: Originally, this was just
+		 *
+		 * r = mpg_integer();
+		 * mpz_mod(r->mpg_i, t1->mpg_i, t2->mpg_i);
+		 *
+		 * But that gave very strange results with negative numerator:
+		 *
+		 *	$ ./gawk -M 'BEGIN { print -15 % 7 }'
+		 *	6
+		 *
+		 * So instead we use mpz_tdiv_qr() to get the correct result
+		 * and just throw away the quotient. We could not find any
+		 * reason why mpz_mod() wasn't working correctly.
+		 */
+		NODE *dummy_quotient;
+
 		r = mpg_integer();
-		mpz_mod(r->mpg_i, t1->mpg_i, t2->mpg_i);
+		dummy_quotient = mpg_integer();
+		mpz_tdiv_qr(dummy_quotient->mpg_i, r->mpg_i, t1->mpg_i, t2->mpg_i);
+		unref(dummy_quotient);
 	} else {
 		mpfr_ptr p1, p2;
 		p1 = MP_FLOAT(t1);