g_float_flag is always true; drop it

Fixes #243

libid/engine/calc_frac_init.cpp

@@ -131,7 +131,6 @@ void calc_frac_init() // initialize a *pile* of stuff for fractal calculation
         || g_debug_flag == DebugFlags::PREVENT_COORDINATE_GRID)
     {
         g_use_grid = false;
-        g_float_flag = true;
     }
     else
     {
@@ -193,17 +192,9 @@ void calc_frac_init() // initialize a *pile* of stuff for fractal calculation
     {
         free_bf_vars();
     }
-    g_float_flag = true;
-    if (g_user_std_calc_mode == 's')
+    if (g_user_std_calc_mode == 's' && g_fractal_type != FractalType::MANDEL)
     {
-        if (g_fractal_type == FractalType::MANDEL)
-        {
-            g_float_flag = true;
-        }
-        else
-        {
-            g_user_std_calc_mode = '1';
-        }
+        g_user_std_calc_mode = '1';
     }
 
     // cppcheck-suppress variableScope
@@ -231,11 +222,6 @@ void calc_frac_init() // initialize a *pile* of stuff for fractal calculation
         g_distance_estimator = 0;    // can't do distest too
     }
 
-    if (g_distance_estimator)
-    {
-        g_float_flag = true;  // force floating point for dist est
-    }
-
     assert(g_cur_fractal_specific == get_fractal_specific(g_fractal_type));
     g_cur_fractal_specific = get_fractal_specific(g_fractal_type);
 
@@ -351,7 +337,7 @@ void calc_frac_init() // initialize a *pile* of stuff for fractal calculation
                 || ratio_bad((double)g_l_y1[(g_logical_screen_x_dots >> 1)-1], ((double)g_l_y_min-g_l_y_3rd)/2))
             {
 expand_retry:
-                g_float_flag = true;                            // switch to floating pt
+                // switch to floating pt
                 if (g_calc_status == CalcStatus::RESUMABLE)     // due to restore of an old file?
                 {
                     g_calc_status = CalcStatus::PARAMS_CHANGED; //   whatever, it isn't resumable

libid/engine/calcfrac.cpp

@@ -2501,23 +2501,14 @@ int potential(double mag, long iterations)
         }
         else   // pot = log(mag) / pow(2.0, (double)pot);
         {
-            if (l_pot < 120 && !g_float_flag) // empirically determined limit of fShift
+            double d_tmp = std::log(mag) / (double) std::pow(2.0, (double) pot);
+            if (d_tmp > FLT_MIN) // prevent float type underflow
             {
-                float f_mag = (float) mag;
-                f_log14(f_mag, f_tmp); // this SHOULD be non-negative
-                f_shift(f_tmp, (char)-l_pot, pot);
+                pot = (float) d_tmp;
             }
             else
             {
-                double d_tmp = std::log(mag)/(double)std::pow(2.0, (double)pot);
-                if (d_tmp > FLT_MIN)   // prevent float type underflow
-                {
-                    pot = (float)d_tmp;
-                }
-                else
-                {
-                    pot = 0.0F;
-                }
+                pot = 0.0F;
             }
         }
 
@@ -2528,15 +2519,7 @@ int potential(double mag, long iterations)
         //    potparam[2] -- rqlim value if changeable (bailout for modulus)
         if (pot > 0.0)
         {
-            if (g_float_flag)
-            {
-                pot = (float)std::sqrt((double)pot);
-            }
-            else
-            {
-                f_sqrt14(pot, f_tmp);
-                pot = f_tmp;
-            }
+            pot = (float) std::sqrt((double) pot);
             pot = (float)(g_potential_params[0] - pot*g_potential_params[1] - 1.0);
         }
         else

libid/include/ui/cmdfiles.h

@@ -215,7 +215,6 @@ extern bool                  g_fast_restore;
 extern int                   g_fill_color;
 extern bool                  g_finite_attractor;
 extern bool                  g_first_init;
-extern bool                  g_float_flag;
 extern std::string           g_formula_filename;
 extern std::string           g_formula_name;
 extern std::string           g_gif_filename_mask;

libid/io/encoder.cpp

@@ -824,7 +824,7 @@ static void setup_save_info(FractalInfo *save_info)
         static_cast<char>(g_three_pass && g_std_calc_mode == '3' ? 127 : g_std_calc_mode);
     save_info->dist_est_old =
         static_cast<std::int16_t>(g_distance_estimator <= 32000 ? g_distance_estimator : 32000);
-    save_info->float_flag = static_cast<std::int16_t>(g_float_flag ? 1 : 0);
+    save_info->float_flag = static_cast<std::int16_t>(1);
     save_info->bailout_old = static_cast<std::int16_t>(g_bailout >= 4 && g_bailout <= 32000 ? g_bailout : 0);
     save_info->calc_time = static_cast<std::int32_t>(g_calc_time);
     save_info->trig_index[0] = static_cast<Byte>(g_trig_index[0]);

libid/io/loadfile.cpp

@@ -1088,13 +1088,10 @@ int read_overlay()      // read overlay/3D files, if reqr'd
     else
     {
         Display3DMode const old_display_ed = g_display_3d;
-        bool const old_float_flag2 = g_float_flag;
         g_display_3d = g_loaded_3d ? Display3DMode::YES : Display3DMode::NONE;   // for <tab> display during next
-        g_float_flag = true; // ditto
         int i = get_video_mode(&read_info, &blk_3_info);
         driver_check_memory();
         g_display_3d = old_display_ed;
-        g_float_flag = old_float_flag2;
         if (i)
         {
             if (blk_2_info.got_data)
@@ -2263,7 +2260,6 @@ int file_get_window()
         free_bf_vars();
     }
     g_bf_math = s_old_bf_math;
-    g_float_flag = true;
 
     return c;
 }

libid/math/biginit.cpp

@@ -177,8 +177,6 @@ static void init_bf2()
         }
     }
 
-    g_float_flag = true;
-
     // Now split up the memory among the pointers
     const auto alloc_size = [&ptr](int size)
     {

libid/ui/cmdfiles.cpp

@@ -122,7 +122,6 @@ bool g_potential_flag{};                                  // continuous potentia
 bool g_potential_16bit{};                                 // store 16 bit continuous potential values
 bool g_dither_flag{};                                     // true if we want to dither GIFs
 bool g_ask_video{};                                       // flag for video prompting
-bool g_float_flag{true};                                  //
 int g_biomorph{};                                         // flag for biomorph
 int g_user_biomorph_value{};                              //
 int g_show_file{};                                        // zero if file display pending

libid/ui/tab_display.cpp

@@ -339,28 +339,9 @@ int tab_display()       // display the status of the current image
     // if (g_bf_math == bf_math_type::NONE)
     ++start_row;
 
-    int j = 0;
-    if (g_display_3d > Display3DMode::NONE)
-    {
-        j = 1;
-    }
-    else if (g_float_flag)
-    {
-        j = 1;
-    }
-
     if (g_bf_math == BFMathType::NONE)
     {
-        if (j)
-        {
-            driver_put_string(start_row, 45, C_GENERAL_HI, "Floating-point");
-            driver_put_string(-1, -1, C_GENERAL_HI,
-                              (j == 1) ? " flag is activated" : " in use (required)");
-        }
-        else
-        {
-            driver_put_string(start_row, 45, C_GENERAL_HI, "Integer math is in use");
-        }
+        driver_put_string(start_row, 45, C_GENERAL_HI, "Floating-point in use");
     }
     else
     {