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Altera_Forum's avatar
Altera_Forum
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10 years ago

how to use the floating point hardware in nios II custom instructions

hi i want to compare the speed difference of floating point calc between custom instruction floating point and software. this is my code:# include <stdio.h># include <altera_avalon_pio_regs....
Altera_Forum's avatar
Altera_Forum
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10 years ago

I think somehow the following lines are not included into your public.mk file found in your BSP folder:

# Hardware Floating Point Custom Instruction without Divider present.

ALT_CFLAGS += -mcustom-fpu-cfg=60-1

ALT_LDFLAGS += -mcustom-fpu-cfg=60-1

What Quartus version are you using? I guess you could open nios2-bsp-editor in the BSP folder and add "-mcustom-fpu-cfg=60-1" into the bsp_cflags_user_user_flags under main>>advanced tab.

Or try to create a new BSP......

The Altera Nios II GCC supports the following builtin functions: https://gcc.gnu.org/onlinedocs/gcc/altera-nios-ii-built-in-functions.html

I guess I am a curious person that likes to try to understand things.