CCS/TMS570LC4357: Branch to _c_int00 From Reset Vector is Not Working

Hi Vishwas,

For Hercules microcontrollers, the location of the exception vector table address is 0x00000000. The start address of _c_int00 needs to be 64-bit aligned. Do you check the memory to make sure the _c_int00 is programed to the address defined in your exception vector table?

Hi Wang,

Yes, I did make sure address of the _c_int00 in Flash is as per table in my original post.

I verified in map file as well as by having a break point at "B _c_int00" and decoding the Branch instruction opcode. I verified the content of memory location in memory browser to make sure _c_int00 location in Flash is as per my table above. As I explained in my original post Branch to _c_int00 from the reset vector is not happening in "Not working" cases. Flash address are correct and there is no overlap with any other section.

Regards,

Vishwas HC

I will try it, then come back to you

Hi Vishwas,

Can you tell me how to program _c_int00() to the locations specified in your post? Isn't it aligned to 32-byte boundary?

Hi Wang,

I am assigning ROM start address for my application in linker cmd file as 0x00201504. I defined global constants variables to get _c_int00() into a specific location in Flash.

Initially when I defined some global constants, I observed behavior as explained in my above post for "Not working" case. Then I deleted some global constants and added more global constants in order to get _c_int00() location in Flash as per "Working" case.

Regards,

Vishwas HC   

Hello Vishwas,

I am sorry I did not get your point. I tested one your not-working location (0x26F808), but it works as expected.

I use "CINT00 : {HL_sys_startup.obj (.text)} > 0x0026F808" in Linker CMD file to place c_int00 to 0x26F808 (refer to my cmd file in the screenshot below):

Hi Wang,

Thanks. I will check this and get back to you.

Regards,

Vishwas HC

Hello Vishwas,

Ok, let me know your test result.

Hi Wang,

In my linker cmd file, align(32) for the Flash address is missing. I think, this is the reason for the issue I am observing. Thanks for your response. After adding align(32) for Flash, issue goes away. 

As per documentation, align(32) directive aligns the Section Program Counter (SPC) at 32-byte boundary. However functions start address like 0x0026F504, 0x0026F57C, 0x0026F808 etc are not 32-byte aligned. With the align(32) in the linker cmd file, I do see many functions start address in the map file which are not 32-byte aligned.

I am not understanding why adding align(32) in the linker cmd file resolves the issue. With align(32) in linker cmd file, will linker allocate functions in Flash with 32 byte aligned?. What is the purpose of align(32) in the linker cmd file? 

Regards,

Vishwas HC