Prevent error when stack overflows

Previously, the stack overflowing would cause the stack pointer to point
outside of the stack, which would cause an error in the stack printing
code.

1 files changed, 3 insertions, 1 deletions

diff --git a/bedrock.js b/bedrock.js
index 99d2319..1b47b63 100644
--- a/bedrock.js
+++ b/bedrock.js
@@ -405,7 +405,9 @@ function EmulatorElement(options) {
     emulator.updateStatePanel = function() {
         function renderStack(stack) {
             let string = '';
-            for (let i=0; i<stack.p; i++) string += hex(stack.mem[i], 2) + ' ';
+            for (let i=0; i<stack.p && i<stack.mem.length; i++) {
+                string += hex(stack.mem[i], 2) + ' ';
+            }
             return string;
         }
         pcState.textContent = hex(br.p, 4);