diff --git a/tinyasm/matinvert.cpp b/tinyasm/matinvert.cpp
index b307c39240..3429f9f464 100644
--- a/tinyasm/matinvert.cpp
+++ b/tinyasm/matinvert.cpp
@@ -3,8 +3,12 @@
 
 
 PetscErrorCode mymatinvert(PetscInt* n, PetscScalar* mat, PetscInt* piv, PetscInt* info, PetscScalar* work) {
-    PetscCallBLAS("LAPACKgetrf",LAPACKgetrf_(n,n,mat,n,piv,info));
-    PetscCallBLAS("LAPACKgetri",LAPACKgetri_(n,mat, n, piv,work,n,info));
+    PetscBLASInt *n_blas, *piv_blas, *info_blas;
+    PetscCall(PetscBLASIntCast(*n, n_blas));
+    PetscCall(PetscBLASIntCast(*piv, piv_blas));
+    PetscCall(PetscBLASIntCast(*info, info_blas));
+    PetscCallBLAS("LAPACKgetrf",LAPACKgetrf_(n_blas, n_blas, mat, n_blas, piv_blas, info_blas));
+    PetscCallBLAS("LAPACKgetri",LAPACKgetri_(n_blas, mat, n_blas, piv_blas, work, n_blas, info_blas));
     return 0;
 }
 
diff --git a/tinyasm/tinyasm.cpp b/tinyasm/tinyasm.cpp
index 6df4793b15..4c78e46be1 100644
--- a/tinyasm/tinyasm.cpp
+++ b/tinyasm/tinyasm.cpp
@@ -49,7 +49,7 @@ class BlockJacobi {
 
                 int numBlocks = dofsPerBlock.size();
                 PetscInt dof;
-                int biggestBlock = 0;
+                PetscInt biggestBlock = 0;
                 for(int p=0; p<numBlocks; p++) {
                     dof = dofsPerBlock[p].size();
                     biggestBlock = max(biggestBlock, dof);
@@ -108,9 +108,10 @@ class BlockJacobi {
 
 
         PetscInt solve(const PetscScalar* __restrict b, PetscScalar* __restrict x) {
-            PetscInt dof, ierr;
+            PetscBLASInt dof;
+            PetscInt ierr;
             PetscScalar dOne = 1.0;
-            PetscInt one = 1;
+            PetscBLASInt one = 1;
             PetscScalar dZero = 0.0;
 
             const PetscScalar *matvalues;
@@ -324,9 +325,9 @@ PetscErrorCode PCView_TinyASM(PC pc, PetscViewer viewer) {
         PetscInt biggestblock = *std::max_element(blocksizes.begin(), blocksizes.end());
         PetscScalar avgblock = std::accumulate(blocksizes.begin(), blocksizes.end(), 0.)/nblocks;
         ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
-        ierr = PetscViewerASCIIPrintf(viewer, "TinyASM (block Jacobi) preconditioner with %d blocks\n", nblocks);CHKERRQ(ierr);
+        ierr = PetscViewerASCIIPrintf(viewer, "TinyASM (block Jacobi) preconditioner with %" PetscInt_FMT " blocks\n", nblocks);CHKERRQ(ierr);
         ierr = PetscViewerASCIIPrintf(viewer, "Average block size %f \n", avgblock);CHKERRQ(ierr);
-        ierr = PetscViewerASCIIPrintf(viewer, "Largest block size %d \n", biggestblock);CHKERRQ(ierr);
+        ierr = PetscViewerASCIIPrintf(viewer, "Largest block size %" PetscInt_FMT " \n", biggestblock);CHKERRQ(ierr);
         ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
     }
     return 0;
@@ -428,6 +429,6 @@ PYBIND11_MODULE(_tinyasm, m) {
               auto blockjacobi = new BlockJacobi(dofsPerBlock, globalDofsPerBlock, localsize, newsf);
               pc->data = (void*)blockjacobi;
               ierr = PetscLogEventEnd(PC_tinyasm_SetASMLocalSubdomains, pc, 0, 0, 0);CHKERRQ(ierr);
-              return ierr;
+              return (int) ierr;
           });
 }