From 108d1ca29275b8310b232e780896ae3bab2f765b Mon Sep 17 00:00:00 2001
From: Steven Hugg <hugg@fasterlight.com>
Date: Mon, 26 Aug 2019 14:09:42 -0400
Subject: [PATCH] vcs: fixed readAddress() bug

---
 src/platform/vcs.ts       | 2 ++
 test/cli/testplatforms.js | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/src/platform/vcs.ts b/src/platform/vcs.ts
index 2cf47ce8..8da33ded 100644
--- a/src/platform/vcs.ts
+++ b/src/platform/vcs.ts
@@ -209,6 +209,8 @@ class VCSPlatform extends BasePlatform {
     // TODO: shouldn't have to do this when debugging
     if (this.lastBreakState && addr >= 0x80 && addr < 0x100)
       return this.getRAMForState(this.lastBreakState)[addr & 0x7f];
+    else if ((addr & 0x1280) === 0x280)
+      return 0; // don't read PIA
     else
       return Javatari.room.console.readAddress(addr);
   }
diff --git a/test/cli/testplatforms.js b/test/cli/testplatforms.js
index 92a672e7..a3b4900a 100644
--- a/test/cli/testplatforms.js
+++ b/test/cli/testplatforms.js
@@ -148,6 +148,11 @@ function testPlatform(platid, romname, maxframes, callback) {
     assert.equal(maxframes, rec.loadFrame(maxframes));
     var state2 = platform.saveState();
     assert.deepEqual(state1, state2);
+    // test memory reads not clearing stuff
+    for (var i=0; i<=0xffff; i++)
+      if (platform.readAddress) platform.readAddress(i);
+    var state3 = platform.saveState();
+    assert.deepEqual(state2, state3);
     // test debug info
     var debugs = platform.getDebugCategories();
     for (var dcat of debugs) {