Hi all,
I like to add some additional instructions to the openrisc. Then I may
need to change the complier to generate the added the instructions.
But It seems that very trouble. I wonder if I could use the inline
assembly function to add the extra instructions in to the c code. And
the complier will generate the corresponding assmbly code. Can the
compiler do it? Thank you very much.

Best Regards,

Stephen

On Thu, 6 May 2004 whli_interqos@yahoo.com.hk wrote: : I like to add some additional instructions to the openrisc. Then I may : need to change the complier to generate the added the instructions. : But It seems that very trouble. I wonder if I could use the inline : assembly function to add the extra instructions in to the c code. And : the complier will generate the corresponding assmbly code. Can the : compiler do it? Thank you very much. Yes, it is possible. But instead of adding them to the compiler (GCC), you add the new instructions to the assembler (GAS) in binutils. ~j

Yes, you can do it with gcc asm statement, without changing gcc or as -- search the mailinng list archive for how to use custom instructions in gcc. Marko On Thursday 06 May 2004 10:49, whli_interqos@yahoo.com.hk wrote:

GCC may support the _emit directive. Also look to see if there is a predefined pseudo function named something like __emit__(arg,...) This is use when multiple arguments are reqired. Borland C++ used this and the GCC team may have borrowed this from them. Next I would suggest crafting #define statements that use the _emit or __emit__ directives. Or you can use the asm (_asm) directive to output data and/or instructions. You must be careful verify that the GCC compiler does not assume involitility of registers or processor state accross your code. If your code modifies the state of something that the compiler thinks has not been modified then it is your responsibility to save and restore those items that the compiler thinks were not modified. Example, assume FOO is your add-on thingie. someVar += value; FOO otherVar += value; If on the first statement the compiler placed value into a register (or temporary stack location) and then assumes at the 3rd statement that the register (or temporary stack location) were not modified then if your FOO thingie modifies the register (or temporary stack location) then it is your responsibility to fix it. GCC may have a #pragma directive that performs a "forget compiler temporaries" that will force the compiler to reconstitute it's state. Have fun, Jim Dempsey ----- Original Message ----- From: whli_interqos@yahoo.com.hk To: openrisc@opencores.org Sent: Thursday, May 06, 2004 3:49 AM Subject: [openrisc] inline assembly Hi all, I like to add some additional instructions to the openrisc. Then I may need to change the complier to generate the added the instructions. But It seems that very trouble. I wonder if I could use the inline assembly function to add the extra instructions in to the c code. And the complier will generate the corresponding assmbly code. Can the compiler do it? Thank you very much. Best Regards, Stephen _______________________________________________ http://www.opencores.org/mailman/listinfo/openrisc -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/openrisc/attachments/20040506/1b19cd88/attachment.htm