Fix a couple of teletext issues.

- update teletst to V1.2, add a couple of additional test cases - don't clear held graphics when text height state didn't change - don't engage graphics when selecting separate/contiguous graphics Fix #164.
tom-seddon · Oct 13, 2021 · c16ac91 · c16ac91
1 parent 564413f
commit c16ac91
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Showing 4 changed files with 26 additions and 13 deletions.
diff --git a/etc/teletest_v1/0/$.TELETST b/etc/teletest_v1/0/$.TELETST
diff --git a/etc/teletest_v1/0/$.TELETST.inf b/etc/teletest_v1/0/$.TELETST.inf
@@ -1 +1 @@
-$.TELETST ffff0e00 ffff0e00
+$.TELETST ffff0e00 ffff802b
diff --git a/etc/teletest_v1/teletst.png b/etc/teletest_v1/teletst.png
diff --git a/src/beeb/src/teletext.cpp b/src/beeb/src/teletext.cpp
@@ -308,21 +308,29 @@ void SAA5050::Byte(uint8_t value, uint8_t dispen) {
 
         case 0x0c:
             // Normal Height
+
+            // State change clears hold graphics state.
+            if (m_raster_shift != 0) {
+                m_last_graphics_data0 = 0;
+                m_last_graphics_data1 = 0;
+                data0 = 0;
+                data1 = 0;
+            }
             m_raster_shift = 0;
-            data0 = 0;
-            data1 = 0;
-            m_last_graphics_data0 = 0;
-            m_last_graphics_data1 = 0;
             break;
 
         case 0x0d:
             // Double Height
-            m_any_double_height = true;
+
+            // State change clears hold graphics state.
+            if (m_raster_shift != 1) {
+                m_last_graphics_data0 = 0;
+                m_last_graphics_data1 = 0;
+                data0 = 0;
+                data1 = 0;
+            }
             m_raster_shift = 1;
-            data0 = 0;
-            data1 = 0;
-            m_last_graphics_data0 = 0;
-            m_last_graphics_data1 = 0;
+            m_any_double_height = true;
             break;
 
         case 0x0e:
@@ -347,7 +355,6 @@ void SAA5050::Byte(uint8_t value, uint8_t dispen) {
             // Graphics
             m_fg = value & 7;
             m_conceal = false;
-        set_charset:;
             m_charset = m_graphics_charset;
             break;
 
@@ -359,12 +366,18 @@ void SAA5050::Byte(uint8_t value, uint8_t dispen) {
         case 0x19:
             // Contiguous Graphics
             m_graphics_charset = TeletextCharset_ContiguousGraphics;
-            goto set_charset;
+            if (m_charset == TeletextCharset_SeparatedGraphics) {
+                m_charset = m_graphics_charset;
+            }
+            break;
 
         case 0x1a:
             // Separated Graphics
             m_graphics_charset = TeletextCharset_SeparatedGraphics;
-            goto set_charset;
+            if (m_charset == TeletextCharset_ContiguousGraphics) {
+                m_charset = m_graphics_charset;
+            }
+            break;
 
         case 0x1b:
             // ESC