4 files changed, 20 insertions, 5 deletions
diff --git a/Build/source/texk/web2c/mplibdir/ChangeLog b/Build/source/texk/web2c/mplibdir/ChangeLog
index a03ed1ac9ec..d289ee5eb1c 100644
--- a/Build/source/texk/web2c/mplibdir/ChangeLog
+++ b/Build/source/texk/web2c/mplibdir/ChangeLog
@@ -1,3 +1,10 @@
+2020-08-21  Luigi Scarso  <luigi.scarso@gmail.com>
+	* Changed epsilon in binary and decimal mode from 1E-52 to
+          2^-173 =~0.835E-52, so that mp_solve_rising_cubic now works as
+          expected.
+	* Fix @<Set the height and depth to zero if the bounding box is empty@>
+          in mp_set_text_box when height and depth are both -inf.
+
 2020-02-18  Luigi Scarso  <luigi.scarso@gmail.com>
 	* better mp_snprintf macro
 
diff --git a/Build/source/texk/web2c/mplibdir/mp.w b/Build/source/texk/web2c/mplibdir/mp.w
index 5f9f174172d..dcbd01b31ea 100644
--- a/Build/source/texk/web2c/mplibdir/mp.w
+++ b/Build/source/texk/web2c/mplibdir/mp.w
@@ -34468,8 +34468,12 @@ void mp_set_text_box (MP mp, mp_text_node p) {
   size_t k, kk; /* current character and character to stop at */
   four_quarters cc;     /* the |char_info| for the current character */
   mp_number h, d;  /* dimensions of the current character */
+  mp_number minus_inf_t; /* check the -inf of height and depth */
   new_number(h);
   new_number(d);
+  new_number(minus_inf_t);
+  number_clone(minus_inf_t, inf_t);
+  number_negate(minus_inf_t);
   set_number_to_zero(p->width);
   set_number_to_neg_inf(p->height);
   set_number_to_neg_inf(p->depth);
@@ -34484,6 +34488,7 @@ void mp_set_text_box (MP mp, mp_text_node p) {
   @<Set the height and depth to zero if the bounding box is empty@>;
   free_number (h);
   free_number (d);
+  free_number (minus_inf_t);
 }
 
 
@@ -34513,7 +34518,10 @@ void mp_set_text_box (MP mp, mp_text_node p) {
 overflow.
 
 @<Set the height and depth to zero if the bounding box is empty@>=
-if (number_to_scaled(p->height) < -number_to_scaled(p->depth)) {
+if (number_equal(p->height,p->depth) && number_equal(p->height,minus_inf_t)) {
+  set_number_to_zero(p->height);
+  set_number_to_zero(p->depth);
+} else if (number_to_scaled(p->height) < -number_to_scaled(p->depth)) {
   set_number_to_zero(p->height);
   set_number_to_zero(p->depth);
 }
diff --git a/Build/source/texk/web2c/mplibdir/mpmathbinary.w b/Build/source/texk/web2c/mplibdir/mpmathbinary.w
index a4312c52cb2..159fae019af 100644
--- a/Build/source/texk/web2c/mplibdir/mpmathbinary.w
+++ b/Build/source/texk/web2c/mplibdir/mpmathbinary.w
@@ -216,7 +216,7 @@ void * mp_initialize_binary_math (MP mp);
 @d equation_threshold 0.001
 @d tfm_warn_threshold 0.0625
 @d warning_limit pow(2.0,52.0)  /* this is a large value that can just be expressed without loss of precision */
-@d epsilon "1E-52"
+@d epsilon  pow(2.0,-173.0)  /* almost "1E-52" */
 @d epsilonf pow(2.0,-52.0)
 @d EL_GORDO   "1E1000000" /* the largest value that \MP\ likes. */
 @d one_third_EL_GORDO (EL_GORDO/3.0)
@@ -255,7 +255,7 @@ void init_binary_constants (void) {
     mpfr_set_si (fraction_one_plus_mpfr_t, (fraction_one+1), ROUNDING);
     mpfr_set_si (angle_multiplier_mpfr_t, angle_multiplier, ROUNDING);
     mpfr_set_str (PI_mpfr_t, PI_STRING, 10, ROUNDING);
-    mpfr_set_str (epsilon_mpfr_t, epsilon, 10, ROUNDING);
+    mpfr_set_d(epsilon_mpfr_t, epsilon , ROUNDING);
     mpfr_set_str (EL_GORDO_mpfr_t, EL_GORDO, 10, ROUNDING);
     initialized = true;
   }
diff --git a/Build/source/texk/web2c/mplibdir/mpmathdecimal.w b/Build/source/texk/web2c/mplibdir/mpmathdecimal.w
index 2ddc216470e..5c2a8fe624e 100644
--- a/Build/source/texk/web2c/mplibdir/mpmathdecimal.w
+++ b/Build/source/texk/web2c/mplibdir/mpmathdecimal.w
@@ -346,7 +346,7 @@ void * mp_initialize_decimal_math (MP mp);
 @d p_over_v_threshold 0x80000 /* TODO */
 @d equation_threshold 0.001
 @d tfm_warn_threshold 0.0625
-@d epsilon "1E-52"
+@d epsilon  pow(2.0,-173.0)   /* almost "1E-52" */
 @d epsilonf pow(2.0,-52.0)
 @d EL_GORDO     "1E1000000" /* the largest value that \MP\ likes. */
 @d warning_limit "1E1000000" /* this is a large value that can just be expressed without loss of precision */
@@ -394,7 +394,7 @@ void * mp_initialize_decimal_math (MP mp) {
     decNumberFromInt32(&fraction_one_plus_decNumber, (fraction_one+1));
     decNumberFromInt32(&angle_multiplier_decNumber, angle_multiplier);
     decNumberFromString(&PI_decNumber, PI_STRING, &set);
-    decNumberFromString(&epsilon_decNumber, epsilon, &set);
+    decNumberFromDouble(&epsilon_decNumber, epsilon);
     decNumberFromString(&EL_GORDO_decNumber, EL_GORDO, &set);
     factorials = (decNumber **)mp_xmalloc(mp,PRECALC_FACTORIALS_CACHESIZE,sizeof(decNumber *));
     factorials[0] = (decNumber *)mp_xmalloc(mp,1,sizeof(decNumber));