kc85: fix ctc/pio chip select pin

floooh · Jul 24, 2024 · d571bb6 · d571bb6
1 parent b5cfa74
commit d571bb6
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/src/common/bitutils.zig b/src/common/bitutils.zig
@@ -24,7 +24,7 @@ pub inline fn pin(bus: anytype, p: comptime_int) bool {
 
 /// test multiple pins against a mask
 pub inline fn pins(bus: anytype, m: comptime_int, p: comptime_int) bool {
-    return (bus & p) == m;
+    return (bus & m) == p;
 }
 
 /// test if all pins are set

diff --git a/src/systems/kc85.zig b/src/systems/kc85.zig
@@ -420,9 +420,13 @@ pub fn Type(comptime model: Model) type {
             // IO address decoding (fixme: replace with a switch?)
             if (pins(bus, CTC.CE_MASK, CTC.CE_PINS)) {
                 bus |= Z80CTC.CE;
+            } else {
+                bus &= ~Z80CTC.CE;
             }
             if (pins(bus, PIO.CE_MASK, PIO.CE_PINS)) {
                 bus |= Z80PIO.CE;
+            } else {
+                bus &= ~Z80PIO.CE;
             }
 
             // tick the CTC and PIO