From 8fb77ff4d4040e9815155501db8d80c3df78a03c Mon Sep 17 00:00:00 2001
From: folkert van heusden <mail@vanheusden.com>
Date: Fri, 12 Apr 2024 21:32:33 +0200
Subject: [PATCH] recover stack when a trap in a trap

---
 cpu.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/cpu.cpp b/cpu.cpp
index 5f82fed..6c5789b 100644
--- a/cpu.cpp
+++ b/cpu.cpp
@@ -1724,8 +1724,15 @@ void cpu::trap(uint16_t vector, const int new_ipl, const bool is_interrupt)
 			if (processing_trap_depth >= 2 && kernel_mode)
 				setRegister(6, 04);
 
-			pushStack(before_psw);
-			pushStack(before_pc);
+			uint16_t prev_sp = getRegister(6);
+			try {
+				pushStack(before_psw);
+				pushStack(before_pc);
+			}
+			catch(const int exception) {
+				// recover stack
+				setRegister(6, prev_sp);
+			}
 
 			processing_trap_depth = 0;