diff --git a/test/sim/common/hazard3_irq.h b/test/sim/common/hazard3_irq.h
index c7f0999..b854172 100644
--- a/test/sim/common/hazard3_irq.h
+++ b/test/sim/common/hazard3_irq.h
@@ -7,6 +7,7 @@
 
 // Should match processor configuration in testbench:
 #define NUM_IRQS 32
+#define MAX_PRIORITY 15
 
 // Declarations for irq_dispatch.S
 extern uintptr_t _external_irq_table[NUM_IRQS];
diff --git a/test/sim/sw_testcases/Makefile b/test/sim/sw_testcases/Makefile
index 1c26d87..e9ef8ee 100644
--- a/test/sim/sw_testcases/Makefile
+++ b/test/sim/sw_testcases/Makefile
@@ -5,6 +5,7 @@ MAX_CYCLES := 1000000
 INCDIR     := include ../common
 
 EXTRA_SRCS_irq_force              := ../common/irq_dispatch.S
+EXTRA_SRCS_irq_top_bottom         := ../common/irq_dispatch.S
 EXTRA_SRCS_irq_preempt_set_in_irq := ../common/irq_dispatch.S
 EXTRA_SRCS_irq_set_all_with_pri   := ../common/irq_dispatch.S
 
diff --git a/test/sim/sw_testcases/irq_preempt_set_in_irq.c b/test/sim/sw_testcases/irq_preempt_set_in_irq.c
index b3bfe99..7dad4cb 100644
--- a/test/sim/sw_testcases/irq_preempt_set_in_irq.c
+++ b/test/sim/sw_testcases/irq_preempt_set_in_irq.c
@@ -40,8 +40,6 @@ EIRQ vector was entered 16 times
 
 *******************************************************************************/
 
-#define MAX_PRIORITY 15
-
 void handler(void);
 
 int main() {
diff --git a/test/sim/sw_testcases/irq_set_all_with_pri.c b/test/sim/sw_testcases/irq_set_all_with_pri.c
index 0a38c8f..e00d3c6 100644
--- a/test/sim/sw_testcases/irq_set_all_with_pri.c
+++ b/test/sim/sw_testcases/irq_set_all_with_pri.c
@@ -54,9 +54,6 @@ EIRQ vector was entered 1 times
 
 *******************************************************************************/
 
-#define PRIORITY_LEVELS 16
-#define NUM_IRQS 32
-
 void handler(void);
 
 int main() {
diff --git a/test/sim/sw_testcases/irq_top_bottom.c b/test/sim/sw_testcases/irq_top_bottom.c
new file mode 100644
index 0000000..f47163e
--- /dev/null
+++ b/test/sim/sw_testcases/irq_top_bottom.c
@@ -0,0 +1,97 @@
+#include "tb_cxxrtl_io.h"
+#include "hazard3_irq.h"
+
+// - Foreground code pends the top-half handler, at maximum priority
+// - Each time the top-half handler is called, it installs a bottom half at
+//   the next descending priority
+// - Each bottom half hander re-pends the top half handler (which immediately
+//   preempts it) to set the next lower-numbered bottom handler
+// - When top returns to bottom, and that bottom returns to the *next* bottom,
+//   which re-pends the top
+// - So on until all handlers have fired
+// - This should stack within two exception frames and enter the EIRQ vector
+//   exactly 16 times (one for each time the top handler runs)
+
+void handler_top() {
+	static int next_bottom = MAX_PRIORITY - 1;
+	tb_puts("Top\n");
+	if (next_bottom >= 0) {
+		h3irq_force_pending(next_bottom--, true);
+	}
+}
+
+void handler_bottom() {
+	int irqnum = h3irq_get_current_irq();
+	tb_printf("Enter bottom %d\n", irqnum);
+	h3irq_force_pending(MAX_PRIORITY, true);
+	tb_printf("Exit bottom %d\n", irqnum);
+}
+
+int main() {
+	global_irq_enable(true);
+	external_irq_enable(true);
+
+	// Set up one IRQ at each priority
+	for (int i = 0; i <= MAX_PRIORITY; ++i) {
+		h3irq_enable(i, true);
+		h3irq_set_priority(i, i);
+		h3irq_set_handler(i, i == MAX_PRIORITY ? handler_top : handler_bottom);
+	}
+
+	h3irq_force_pending(MAX_PRIORITY, true);
+
+	tb_printf("EIRQ vector was entered %d times\n", _external_irq_entry_count);
+	return 0;
+}
+
+/*EXPECTED-OUTPUT***************************************************************
+
+Top
+Enter bottom 14
+Top
+Exit bottom 14
+Enter bottom 13
+Top
+Exit bottom 13
+Enter bottom 12
+Top
+Exit bottom 12
+Enter bottom 11
+Top
+Exit bottom 11
+Enter bottom 10
+Top
+Exit bottom 10
+Enter bottom 9
+Top
+Exit bottom 9
+Enter bottom 8
+Top
+Exit bottom 8
+Enter bottom 7
+Top
+Exit bottom 7
+Enter bottom 6
+Top
+Exit bottom 6
+Enter bottom 5
+Top
+Exit bottom 5
+Enter bottom 4
+Top
+Exit bottom 4
+Enter bottom 3
+Top
+Exit bottom 3
+Enter bottom 2
+Top
+Exit bottom 2
+Enter bottom 1
+Top
+Exit bottom 1
+Enter bottom 0
+Top
+Exit bottom 0
+EIRQ vector was entered 16 times
+
+*******************************************************************************/