diff --git a/kernel/x86_64/sgemm_kernel_16x4_skylakex.c b/kernel/x86_64/sgemm_kernel_16x4_skylakex.c
index 4177ae2dc..76b82e65b 100644
--- a/kernel/x86_64/sgemm_kernel_16x4_skylakex.c
+++ b/kernel/x86_64/sgemm_kernel_16x4_skylakex.c
@@ -1215,7 +1215,7 @@ CNAME(BLASLONG m, BLASLONG n, BLASLONG k, float alpha, float * __restrict A, flo
 
 int sgemm_kernel_direct_performant(BLASLONG M, BLASLONG N, BLASLONG K)
 {
-	unsigned long mnk = M * N * K;
+	unsigned long long mnk = M * N * K;
 	/* large matrixes -> not performant */
 	if (mnk >= 28 * 512 * 512)
 		return 0;