diff --git a/Makefile b/Makefile
index 509b228..38dae5b 100644
--- a/Makefile
+++ b/Makefile
@@ -25,5 +25,6 @@ emu6502: memtest6502
 	gcc -D_END=$$(cat tmp/memtest4k-f000-ascii.map | grep ^done, | cut -d, -f2 | tr -d ' ,') -o out/emu6502 src/emu6502.c src/fake6502.c
 
 test: memtest6502
-	gcc -DNOLIMIT -D_END=$$(cat tmp/memtest4k-f000-ascii.map | grep ^done, | cut -d, -f2 | tr -d ' ,') -o out/emu6502 src/emu6502.c src/fake6502.c
+	# Run the emulator, but terminate after 10M instructions
+	gcc -D_LIMIT=10000000 -D_END=$$(cat tmp/memtest4k-f000-ascii.map | grep ^done, | cut -d, -f2 | tr -d ' ,') -o out/emu6502 src/emu6502.c src/fake6502.c
 	out/emu6502 | tail -30
diff --git a/src/emu6502.c b/src/emu6502.c
index 5719bb2..e47a762 100644
--- a/src/emu6502.c
+++ b/src/emu6502.c
@@ -84,7 +84,12 @@ int main() {
   reset6502();
   signal(SIGINT, intv);
   while (1) {
-#ifndef NOLIMIT
+#ifdef _LIMIT
+    if (instructions >= _LIMIT) {
+      dprintf(2, "Prematurely terminated after %d instructions (limit exceeded)", instructions);
+      exit(2);
+    }
+#else
     usleep(1);
 #endif
     step6502();