Supporting undocumented ECS bits in SPRxCTL (#692)

dirkwhoffmann · May 19, 2022 · 926152b · 926152b
1 parent 70a4348
commit 926152b
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Showing 3 changed files with 10 additions and 6 deletions.
diff --git a/Emulator/Agnus/Agnus.cpp b/Emulator/Agnus/Agnus.cpp
@@ -346,9 +346,6 @@ Agnus::executeUntilBusIsFreeForCIA()
 
     // Sync with the E clock driving the CIA
     syncWithEClock();
-
-    // Assign bus to the CPU
-    // busOwner[pos.h] = BUS_CPU;
 }
 
 void

diff --git a/Emulator/Agnus/AgnusRegs.cpp b/Emulator/Agnus/AgnusRegs.cpp
@@ -450,6 +450,16 @@ Agnus::pokeSPRxCTL(u16 value)
     sprVStrt[x] = (i16)((value & 0b100) << 6 | (sprVStrt[x] & 0x00FF));
     sprVStop[x] = (i16)((value & 0b010) << 7 | (value >> 8));
 
+    // ECS Agnus supports an additional position bit (encoded in 'unused' area)
+    if (GET_BIT(value, 6)) {
+        trace(XFILES, "XFILES: pokeSPRxCTL: Extended VSTRT bit set\n");
+        if (isECS()) sprVStrt[x] |= 0x0200;
+    }
+    if (GET_BIT(value, 7)) {
+        trace(XFILES, "XFILES: pokeSPRxCTL: Extended VSTOP bit set\n");
+        if (isECS()) sprVStop[x] |= 0x0200;
+    }
+
     // Update sprite DMA status
     if (sprVStrt[x] == v) sprDmaState[x] = SPR_DMA_ACTIVE;
     if (sprVStop[x] == v) sprDmaState[x] = SPR_DMA_IDLE;

diff --git a/Emulator/Denise/DeniseRegs.cpp b/Emulator/Denise/DeniseRegs.cpp
@@ -331,9 +331,6 @@ Denise::pokeSPRxCTL(u16 value)
 
     // 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
     // L7 L6 L5 L4 L3 L2 L1 L0 AT  -  -  -  - E8 L8 H0  (Lx = VSTOP)
-
-    // Disarm the sprite
-    // CLR_BIT(armed, x);
 
     // Record the register change
     i64 pos = 4 * (agnus.pos.h + 1);