topic What is r13 used for in PowerPC architecture in CodeWarrior Development Tools https://community.nxp.com/t5/CodeWarrior-Development-Tools/What-is-r13-used-for-in-PowerPC-architecture/m-p/791716#M6950 <HTML><HEAD></HEAD><BODY><P>Morning, everyone:</P><P></P><P>I am using the Codewarrior ver8.8 for debuging the MPC855T. I have found that in the interrupt processing function, once after restoring the r13, when it reach a global variation, the debug would send an Exception, which is a Machine check Exception. So what is the r13 used for, and how would restoring it cause the exception?</P><P></P><P>I also refer to the new found project. In the group runtime, there is a Interrupt vector file eppc_exception.asm. And found that the saved and restored GPRs not including the r13-r31. As I know, r14-r31 is the temporary registers, non-volatile.When an interrupt occurs, how protect the registers from altering? Does&nbsp;the Codewarrior compiler add some codes to save them?</P><P></P><P>Any discussion and reply will be appreciated.</P><P></P><P>Thanks and good day!</P><P></P><P>BR,</P><P>Jinyu.</P></BODY></HTML> Thu, 16 Aug 2018 02:06:16 GMT jinyu_zhang 2018-08-16T02:06:16Z What is r13 used for in PowerPC architecture https://community.nxp.com/t5/CodeWarrior-Development-Tools/What-is-r13-used-for-in-PowerPC-architecture/m-p/791716#M6950 <HTML><HEAD></HEAD><BODY><P>Morning, everyone:</P><P></P><P>I am using the Codewarrior ver8.8 for debuging the MPC855T. I have found that in the interrupt processing function, once after restoring the r13, when it reach a global variation, the debug would send an Exception, which is a Machine check Exception. So what is the r13 used for, and how would restoring it cause the exception?</P><P></P><P>I also refer to the new found project. In the group runtime, there is a Interrupt vector file eppc_exception.asm. And found that the saved and restored GPRs not including the r13-r31. As I know, r14-r31 is the temporary registers, non-volatile.When an interrupt occurs, how protect the registers from altering? Does&nbsp;the Codewarrior compiler add some codes to save them?</P><P></P><P>Any discussion and reply will be appreciated.</P><P></P><P>Thanks and good day!</P><P></P><P>BR,</P><P>Jinyu.</P></BODY></HTML> Thu, 16 Aug 2018 02:06:16 GMT https://community.nxp.com/t5/CodeWarrior-Development-Tools/What-is-r13-used-for-in-PowerPC-architecture/m-p/791716#M6950 jinyu_zhang 2018-08-16T02:06:16Z