1 files changed, 2 insertions, 1 deletions

diff --git a/libsmctrl.c b/libsmctrl.c
index 69b19a1..640001a 100644
--- a/libsmctrl.c
+++ b/libsmctrl.c
@@ -281,6 +281,7 @@ static int read_int_procfile(char* filename, uint64_t* out) {
 }
 
 static uint64_t tpc_mask_per_gpc_per_dev[16][12];
+// Output mask is vtpc-indexed (virtual TPC)
 int libsmctrl_get_gpc_info(uint32_t* num_enabled_gpcs, uint64_t** tpcs_for_gpc, int dev) {
         uint32_t i, j, vtpc_idx = 0;
         uint64_t gpc_mask, num_tpc_per_gpc, max_gpcs, gpc_tpc_mask;
@@ -322,7 +323,7 @@ int libsmctrl_get_gpc_info(uint32_t* num_enabled_gpcs, uint64_t** tpcs_for_gpc,
                                 // Skip disabled TPCs
                                 if ((1 << j) & gpc_tpc_mask)
                                         continue;
-                                *tpc_mask |= (1 << vtpc_idx);
+                                *tpc_mask |= (1ull << vtpc_idx);
                                 vtpc_idx++;
                 }
         }