Added LPEN b0 support over main screen

LPEN b0 now reflects b0 of the first ASIC display byte over the main screen area, in addition to BCD0 of the border colour in border regions.
simonowen · May 27, 2020 · 40ee9a5 · 40ee9a5
1 parent 8b10ee7
commit 40ee9a5
Showing 1 changed file with 10 additions and 11 deletions.
diff --git a/Base/SAMIO.cpp b/Base/SAMIO.cpp
@@ -300,15 +300,18 @@ static uint8_t update_lpen()
     {
         int line = g_dwCycleCounter / TSTATES_PER_LINE, line_cycle = g_dwCycleCounter % TSTATES_PER_LINE;
 
-        if (!IsScreenLine(line) || line_cycle < (BORDER_PIXELS + BORDER_PIXELS))
+        if (IsScreenLine(line) && line_cycle >= (BORDER_PIXELS + BORDER_PIXELS))
         {
-            lpen = (lpen & LPEN_TXFMST) | (border & 1);
+            uint8_t b1, b2, b3, b4;
+            Frame::GetAsicData(&b1, &b2, &b3, &b4);
+
+            auto xpos = static_cast<uint8_t>(line_cycle - (BORDER_PIXELS + BORDER_PIXELS));
+            auto b0 = (line_cycle < (BORDER_PIXELS + BORDER_PIXELS)) ? (border & 1) : (b1 & 1);
+            lpen = (xpos & 0xfc) | (lpen & LPEN_TXFMST) | b0;
         }
         else
         {
-            auto xpos = static_cast<uint8_t>(line_cycle - (BORDER_PIXELS + BORDER_PIXELS));
-            auto b0 = (xpos < VIDEO_DELAY&& line == TOP_BORDER_LINES) ? 1 : xpos ? 0 : 1;
-            lpen = (xpos & 0xfc) | (lpen & LPEN_TXFMST) | b0;
+            lpen = (lpen & LPEN_TXFMST) | (border & 1);
         }
     }
 
@@ -322,7 +325,7 @@ static uint8_t update_hpen()
         int line = g_dwCycleCounter / TSTATES_PER_LINE, line_cycle = g_dwCycleCounter % TSTATES_PER_LINE;
 
         if (IsScreenLine(line) && (line != TOP_BORDER_LINES || line_cycle >= (BORDER_PIXELS + BORDER_PIXELS)))
-            hpen = line -TOP_BORDER_LINES;
+            hpen = line - TOP_BORDER_LINES;
         else
             hpen = SCREEN_LINES;
     }
@@ -504,16 +507,12 @@ BYTE In(WORD wPort_)
             bRet = pDallas->In(wPort_);
         break;
 
-        // HPEN and LPEN ports
     case LPEN_PORT:
-    {
-        // Simulated a disconnected light pen, with LPEN/HPEN tracking the raster position.
         if ((wPort_ & PEN_MASK) == LPEN_PORT)
             bRet = update_lpen();
-        else // HPEN
+        else
             bRet = update_hpen();
         break;
-    }
 
     // Spectrum ATTR port
     case ATTR_PORT: