Asm code and C imme

Altera_Forum · ‎12-27-2005

Hi,

In my project, I define a imme in *.c file:

#define SPI_0_BASE 0x00800980

In one of my asm routine, I wanna use this imme, how could I do?

asm("movhi r15,%hi(SPI_0_BASE)");

I have tried the expression above, but compiling error occur and told me that SPI_0_BASE was undefined.

Thanks any help,

David

Altera_Forum · ‎12-27-2005

--- Quote Start ---

originally posted by david_cai@Dec 27 2005, 06:47 AM

#define spi_0_base 0x00800980

in one of my asm routine, i wanna use this imme, how could i do?

asm("movhi r15,%hi(spi_0_base)");

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=11793)

--- quote end ---

--- Quote End ---

It does not work because the symbol is inside " "...

I do not know any escape unless you either substitute the symbol by hand or you rewrite the statement in C ...

bye

PJ

Altera_Forum · ‎01-05-2006

Maybe try like this example :

#define CUSTOM_INSTRUCTION_TEST 6
//expand the contents of val to "xxx"# define _str_(val)# val# define __str__(val) _str_(val)
__asm__ volatile ("custom " __str__(CUSTOM_INSTRUCTION_TEST) ", r0, r0, r0");

This generates :

custom 6,r0,r0,r0

For your problem, maybe this should work in the same way

__asm__ volatile ("movhi r15,%hi" __str__(SPI_0_BASE));

Altera_Forum · ‎01-06-2006

Hi svhb,

I have tried your method, but the following error occurred:

{standard input}:241: Error: badly formed expression near %hi0x00800980

http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/blink.gif

Altera_Forum · ‎01-06-2006

Try with brackets around the value?

__asm__ volatile ("movhi r15,%hi(" __str__(SPI_0_BASE) ")");

Stefaan

Altera_Forum · ‎01-06-2006

check gcc document for the inline asm's args format, there are input regs, and output regs.

search the linux-2.6.x/include/asm-nios2nommu for some example.

Altera_Forum · ‎01-06-2006

--- Quote Start ---

originally posted by hippo@Jan 6 2006, 08:37 PM

check gcc document for the inline asm's args format, there are input regs, and output regs.

search the linux-2.6.x/include/asm-nios2nommu/io.h for some example.

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=12010)

--- quote end ---

--- Quote End ---

Altera_Forum · ‎01-10-2006

An excellent description of gcc inline assembly can be found here:

http://www.ibiblio.org/gferg/ldp/gcc-inlin...mbly-howto.html (http://www.ibiblio.org/gferg/ldp/gcc-inline-assembly-howto.html)

also, check the nios2.h file.

--wolf