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Author: jonas-schievink

cortex-m-rt/asm.S

@@ -94,6 +94,10 @@ Reset:
 #endif
 
 4:
+  # Preserve `lr` and emit debuginfo that lets external tools restore it.
+  # This fixes unwinding past the `Reset` handler.
+  # See https://sourceware.org/binutils/docs/as/CFI-directives.html for an
+  # explanation of the directives.
 .cfi_def_cfa sp, 0
   push {lr}
 .cfi_offset lr, 0