Fix AGA HAM detection (only 6 or 8 planes)

diff --git a/custom.cpp b/custom.cpp
index 7923727ef1703ef7a58922287009081c1e9eb9bb..521f57a71eb5bd1570c3038a38d55aed711187ea 100644 (file)
--- a/custom.cpp
+++ b/custom.cpp
@@ -5193,11 +5193,31 @@ static bool issprbrd(int hpos, uae_u16 bplcon0, uae_u16 bplcon3)
        return brdsprt && !ce_is_borderblank(current_colors.extra);
 }
 
+static bool isham(uae_u16 bplcon0)
+{
+       int p = GET_PLANES(bplcon0);
+       if (!(bplcon0 & 0x800))
+               return 0;
+       if (aga_mode) {
+               // AGA only has 6 or 8 plane HAM
+               if (p == 6 || p == 8)
+                       return 1;
+       } else {
+               // OCS/ECS also supports 5 plane HAM
+               if (GET_RES_DENISE(bplcon0) > 0)
+                       return 0;
+               if (p >= 5)
+                       return 1;
+       }
+       return 0;
+}
+
 static void record_register_change(int hpos, int regno, uae_u16 value)
 {
        if (regno == 0x0100 || regno == 0x0101) { // BPLCON0
-               if (value & 0x800)
-                       thisline_decision.ham_seen = 1;
+               if (value & 0x800) {
+                       thisline_decision.ham_seen |= isham(value);
+               }
                thisline_decision.ehb_seen |= isehb(value, bplcon2);
                isbrdblank(hpos, value, bplcon3);
                issprbrd(hpos, value, bplcon3);
@@ -6194,7 +6214,7 @@ static void reset_decisions_hsync_start(void)
        thisline_decision.plfleft = -1;
        thisline_decision.plflinelen = -1;
        thisline_decision.plfright = -1;
-       thisline_decision.ham_seen = (bplcon0 & 0x800) != 0;
+       thisline_decision.ham_seen = isham(bplcon0);
        thisline_decision.ehb_seen = isehb(bplcon0, bplcon2);
        thisline_decision.ham_at_start = (bplcon0 & 0x800) != 0;
        thisline_decision.bordersprite_seen = issprbrd(-1, bplcon0, bplcon3);