CRC Nios II Custom Instruction

Hi,

I follow the "Nios II Custom Instruction user guide" and the hw and sw files

"ug_custom_instruction_files".

I didnt secceed 2 operate the example in the command shell, so I opend project in the Nios2 IDE.

I get a build error:

**** Build of configuration Debug for project CRC ****

make -s all includes

Linking CRC.elf...

obj/crc_main.o(.text+0x148): In function `main':

../crc_main.c:138: undefined reference to `alt_timestamp_start'

obj/crc_main.o(.text+0x180):../crc_main.c:148: undefined reference to `alt_timestamp'

obj/crc_main.o(.text+0x1e4):../crc_main.c:153: undefined reference to `alt_timestamp'

obj/crc_main.o(.text+0x214):../crc_main.c:161: undefined reference to `alt_timestamp'

obj/crc_main.o(.text+0x278):../crc_main.c:166: undefined reference to `alt_timestamp'

obj/crc_main.o(.text+0x2a4):../crc_main.c:173: undefined reference to `alt_timestamp'

obj/crc_main.o(.text+0x308):../crc_main.c:178: more undefined references to `alt_timestamp' follow

obj/crc_main.o(.text+0x4bc): In function `main':

../crc_main.c:201: undefined reference to `alt_timestamp_freq'

obj/crc_main.o(.text+0x5b0):../crc_main.c:202: undefined reference to `alt_timestamp_freq'

obj/crc_main.o(.text+0x6a4):../crc_main.c:203: undefined reference to `alt_timestamp_freq'

obj/crc_main.o(.text+0x7b0):../crc_main.c:207: undefined reference to `alt_timestamp_freq'

obj/crc_main.o(.text+0x8c4):../crc_main.c:208: undefined reference to `alt_timestamp_freq'

obj/crc_main.o(.text+0x9d8):../crc_main.c:209: more undefined references to `alt_timestamp_freq' follow

collect2: ld returned 1 exit status

make: *** [CRC.elf] Error 1

Build completed in 3.187 seconds

How can I solve that error?

Tahnx in advance.