Frame Buffer: overide OS_ReadPoint when framebuffer active

Change-Id: I7152005ecba1e751bcf97438ac3e93e0ee22dd8d

src/framebuffer/primitives.c

@@ -568,6 +568,14 @@ void prim_set_pixel(screen_mode_t *screen, int x, int y, pixel_t colour) {
    set_pixel(screen, x, y, colour);
 }
 
+pixel_t prim_get_pixel(screen_mode_t *screen, int x, int y) {
+   return get_pixel(screen, x, y);
+}
+
+int prim_on_screen(screen_mode_t *screen, int x, int y) {
+   return x >= g_x_min && x <= g_x_max && y >= g_y_min && y <= g_y_max;
+}
+
 // Rodders: Line mode support
 // Implementation of Bresenham's line drawing algorithm from here:
 // http://tech-algorithm.com/articles/drawing-line-using-bresenham-algorithm/

src/framebuffer/primitives.h

@@ -21,31 +21,32 @@ typedef enum {
    PM_INVERT = 4
 } plotmode_t;
 
-void prim_set_fg_plotmode      (plotmode_t plotmode);
-plotmode_t prim_get_fg_plotmode();
-void prim_set_bg_plotmode      (plotmode_t plotmode);
-plotmode_t prim_get_bg_plotmode();
-void prim_set_graphics_area    (screen_mode_t *screen, int16_t x1, int16_t y1, int16_t x2, int16_t y2);
-void prim_clear_graphics_area  (screen_mode_t *screen, pixel_t colour);
-void prim_set_pixel            (screen_mode_t *screen, int x, int y, pixel_t colour);
-void prim_draw_line            (screen_mode_t *screen, int x1, int y1, int x2, int y2, pixel_t colour, uint8_t linemode);
-void prim_flood_fill           (screen_mode_t *screen, int x, int y, pixel_t fill_col, pixel_t ref_col, int c);
-void prim_fill_area            (screen_mode_t *screen, int x, int y, pixel_t colour, fill_t mode);
-void prim_draw_circle          (screen_mode_t *screen, int xc, int yc, int xr, int yr, pixel_t colour);
-void prim_fill_circle          (screen_mode_t *screen, int xc, int yc, int xr, int yr, pixel_t colour);
-void prim_draw_ellipse         (screen_mode_t *screen, int xc, int yc, int width, int height, int shear, pixel_t colour);
-void prim_fill_ellipse         (screen_mode_t *screen, int xc, int yc, int width, int height, int shear, pixel_t colour);
-void prim_fill_triangle        (screen_mode_t *screen, int x1, int y1, int x2, int y2, int x3, int y3, pixel_t colour);
-void prim_draw_arc             (screen_mode_t *screen, int xc, int yc, int x1, int y1, int x2, int y2, pixel_t colour);
-void prim_fill_chord           (screen_mode_t *screen, int xc, int yc, int x1, int y1, int x2, int y2, pixel_t colour);
-void prim_fill_sector          (screen_mode_t *screen, int xc, int yc, int x1, int y1, int x2, int y2, pixel_t colour);
-void prim_move_copy_rectangle  (screen_mode_t *screen, int x1, int y1, int x2, int y2, int x3, int y3, int move);
-void prim_fill_rectangle       (screen_mode_t *screen, int x1, int y1, int x2, int y2, pixel_t colour);
-void prim_fill_parallelogram   (screen_mode_t *screen, int x1, int y1, int x2, int y2, int x3, int y3, pixel_t colour);
-void prim_draw_character       (screen_mode_t *screen, int c, int x_pos, int y_pos, pixel_t colour);
-
-void prim_reset_sprites        (screen_mode_t *screen);
-void prim_define_sprite        (screen_mode_t *screen, int n, int x1, int y1, int x2, int y2);
-void prim_draw_sprite          (screen_mode_t *screen, int n, int x, int y);
+void       prim_set_fg_plotmode      (plotmode_t plotmode);
+plotmode_t prim_get_fg_plotmode      ();
+void       prim_set_bg_plotmode      (plotmode_t plotmode);
+plotmode_t prim_get_bg_plotmode      ();
+void       prim_set_graphics_area    (screen_mode_t *screen, int16_t x1, int16_t y1, int16_t x2, int16_t y2);
+void       prim_clear_graphics_area  (screen_mode_t *screen, pixel_t colour);
+void       prim_set_pixel            (screen_mode_t *screen, int x, int y, pixel_t colour);
+pixel_t    prim_get_pixel            (screen_mode_t *screen, int x, int y);
+int        prim_on_screen            (screen_mode_t *screen, int x, int y);
+void       prim_draw_line            (screen_mode_t *screen, int x1, int y1, int x2, int y2, pixel_t colour, uint8_t linemode);
+void       prim_flood_fill           (screen_mode_t *screen, int x, int y, pixel_t fill_col, pixel_t ref_col, int c);
+void       prim_fill_area            (screen_mode_t *screen, int x, int y, pixel_t colour, fill_t mode);
+void       prim_draw_circle          (screen_mode_t *screen, int xc, int yc, int xr, int yr, pixel_t colour);
+void       prim_fill_circle          (screen_mode_t *screen, int xc, int yc, int xr, int yr, pixel_t colour);
+void       prim_draw_ellipse         (screen_mode_t *screen, int xc, int yc, int width, int height, int shear, pixel_t colour);
+void       prim_fill_ellipse         (screen_mode_t *screen, int xc, int yc, int width, int height, int shear, pixel_t colour);
+void       prim_fill_triangle        (screen_mode_t *screen, int x1, int y1, int x2, int y2, int x3, int y3, pixel_t colour);
+void       prim_draw_arc             (screen_mode_t *screen, int xc, int yc, int x1, int y1, int x2, int y2, pixel_t colour);
+void       prim_fill_chord           (screen_mode_t *screen, int xc, int yc, int x1, int y1, int x2, int y2, pixel_t colour);
+void       prim_fill_sector          (screen_mode_t *screen, int xc, int yc, int x1, int y1, int x2, int y2, pixel_t colour);
+void       prim_move_copy_rectangle  (screen_mode_t *screen, int x1, int y1, int x2, int y2, int x3, int y3, int move);
+void       prim_fill_rectangle       (screen_mode_t *screen, int x1, int y1, int x2, int y2, pixel_t colour);
+void       prim_fill_parallelogram   (screen_mode_t *screen, int x1, int y1, int x2, int y2, int x3, int y3, pixel_t colour);
+void       prim_draw_character       (screen_mode_t *screen, int c, int x_pos, int y_pos, pixel_t colour);
+void       prim_reset_sprites        (screen_mode_t *screen);
+void       prim_define_sprite        (screen_mode_t *screen, int n, int x1, int y1, int x2, int y2);
+void       prim_draw_sprite          (screen_mode_t *screen, int n, int x, int y);
 
 #endif

src/framebuffer/swi_impl.c

@@ -6,6 +6,7 @@
 #include "../tube-lib.h"
 #include "../tube-swi.h"
 
+#include "primitives.h"
 #include "framebuffer.h"
 #include "screen_modes.h"
 
@@ -354,6 +355,47 @@ static void OS_ReadVduVariables_impl(unsigned int *reg) {
    }
 }
 
+// ==========================================================================
+// Implementation of OS_ReadPoint SWI
+// ==========================================================================
+
+// Entry
+//   R0	X co-ordinate
+//   R1	Y co-ordinate
+// Exit
+//   R0	Preserved
+//   R1	Preserved
+//   R2	Colour
+//   R3	Tint
+//   R4	-1 if point was off screen, else 0
+// Notes
+//   If in a 16 or 32 bpp mode, this will return the 15 or 24 bit
+//   colour number in R2 and tint will be 0.
+
+static void OS_ReadPoint_impl(unsigned int *reg) {
+   int32_t x = (int32_t)reg[0];
+   int32_t y = (int32_t)reg[1];
+
+   screen_mode_t *screen = get_screen_mode(fb_get_current_screen_mode());
+
+   pixel_t colour = prim_get_pixel(screen, x, y);
+
+   if (prim_on_screen(screen, x, y)) {
+      if (screen->log2bpp == 3) {
+         reg[2] = colour & 0x3F;
+         reg[3] = colour & 0xC0;
+      } else {
+         reg[2] = colour;
+         reg[3] = 0;
+      }
+      reg[4] = 0;
+   } else {
+      reg[2] = -1;
+      reg[3] = 0;
+      reg[4] = -1;
+   }
+}
+
 // ==========================================================================
 // Public methods
 // ==========================================================================
@@ -384,6 +426,7 @@ void fb_add_swi_handlers() {
    SWI_Table[SWI_OS_Byte].handler             = OS_Byte_impl;
    SWI_Table[SWI_OS_ReadLine].handler         = OS_ReadLine_impl;
    SWI_Table[SWI_OS_ScreenMode].handler       = OS_ScreenMode_impl;
+   SWI_Table[SWI_OS_ReadPoint].handler        = OS_ReadPoint_impl;
    SWI_Table[SWI_OS_ReadModeVariable].handler = OS_ReadModeVariable_impl;
    SWI_Table[SWI_OS_ReadVduVariables].handler = OS_ReadVduVariables_impl;