plic: Fix enable bit pointer calculation

1 files changed, 4 insertions, 3 deletions

diff --git a/src/plic.zig b/src/plic.zig
index 3529cb2..7d2d032 100644
--- a/src/plic.zig
+++ b/src/plic.zig
@@ -38,14 +38,15 @@ pub const Plic = struct {
         if (interrupt == 0) return Error.InterruptOutOfRange;
 
         const mmio_slice = self.mmioSlice();
-        const enable_ptr: *volatile [num_contexts]u32 = @alignCast(@ptrCast(&mmio_slice[enable_offset]));
+        const enable_ptr: *volatile [num_contexts][32]u32 = @alignCast(@ptrCast(&mmio_slice[enable_offset]));
 
+        const register = interrupt / 32;
         const bit = @as(u32, 1) << @intCast(interrupt & 0x1f);
 
         if (enable) {
-            enable_ptr[context] |= bit;
+            enable_ptr[context][register] |= bit;
         } else {
-            enable_ptr[context] &= ~bit;
+            enable_ptr[context][register] &= ~bit;
         }
     }