On Wed, 17 Aug 2016, peter green wrote: > However the compiler doesn't know whether you will be mixing the arm code it > built with thumb code built with another compiler invocation. So it uses BX > for function calls and returns. Hmm, so it uses BX LR just in case LR has bit 0 set (to return to Thumb code)? -- Adam Wysocki http://www.chmurka.net/