1 files changed, 12 insertions, 6 deletions

diff --git a/build.rs b/build.rs
index 7c518c90..ff9ebe35 100644
--- a/build.rs
+++ b/build.rs
@@ -7,15 +7,21 @@ fn main() {
         println!("cargo:rustc-cfg=rustc_is_nightly");
     }
 
-    if target.starts_with("thumbv6m") {
-        println!("cargo:rustc-cfg=armv6m");
-    }
-
+    // These targets all have know support for the BASEPRI register.
     if target.starts_with("thumbv7m")
         | target.starts_with("thumbv7em")
-        | target.starts_with("thumbv8m")
+        | target.starts_with("thumbv8m.main")
+    {
+        println!("cargo:rustc-cfg=have_basepri");
+
+    // These targets are all known to _not_ have the BASEPRI register.
+    } else if target.starts_with("thumb")
+        && !(target.starts_with("thumbv6m") | target.starts_with("thumbv8m.base"))
     {
-        println!("cargo:rustc-cfg=armv7m");
+        panic!(
+            "Unknown target '{}'. Need to update BASEPRI logic in build.rs.",
+            target
+        );
     }
 
     println!("cargo:rerun-if-changed=build.rs");