Test debugging code with interrupts.

3 files changed, 34 insertions, 4 deletions

diff --git a/debug/programs/entry.S b/debug/programs/entry.S
index a2ea955..97b62a3 100755
--- a/debug/programs/entry.S
+++ b/debug/programs/entry.S
@@ -1,8 +1,6 @@
 #include "encoding.h"
 
-// Enough stack to store every register in case a trap handler is executed,
-// plus 33 more values.
-#define STACK_SIZE (64 * XLEN / 8)
+#define STACK_SIZE (74 * XLEN / 8)
 
 #if XLEN == 64
 # define LREG ld
diff --git a/debug/programs/init.c b/debug/programs/init.c
index 9933c23..8b047de 100644
--- a/debug/programs/init.c
+++ b/debug/programs/init.c
@@ -17,7 +17,7 @@ void enable_timer_interrupts()
     set_csr(mstatus, MSTATUS_MIE);
 }
 
-void handle_trap(unsigned int mcause, unsigned int mepc, unsigned int sp)
+void handle_trap(unsigned int mcause, void *mepc, void *sp)
 {
     unsigned hartid = csr_read(mhartid);
     if (trap_handler[hartid]) {
diff --git a/debug/programs/interrupt.c b/debug/programs/interrupt.c
new file mode 100644
index 0000000..c2dd5ec
--- /dev/null
+++ b/debug/programs/interrupt.c
@@ -0,0 +1,32 @@
+#include "init.h"
+#include "encoding.h"
+
+static volatile unsigned interrupt_count;
+static volatile unsigned local;
+
+static unsigned delta = 0x100;
+void *increment_count(unsigned hartid, unsigned mcause, void *mepc, void *sp)
+{
+    interrupt_count++;
+    // There is no guarantee that the interrupt is cleared immediately when
+    // MTIMECMP is written, so stick around here until that happens.
+    while (csr_read(mip) & MIP_MTIP) {
+        MTIMECMP[hartid] = MTIME + delta;
+    }
+    return mepc;
+}
+
+int main()
+{
+    interrupt_count = 0;
+    local = 0;
+    unsigned hartid = csr_read(mhartid);
+
+    set_trap_handler(increment_count);
+    MTIMECMP[hartid] = MTIME - 1;
+    enable_timer_interrupts();
+
+    while (1) {
+        local++;
+    }
+}