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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
Icon for Honored Contributor rankHonored Contributor
10 years ago

okay, I think I know what is the problem, the system.h is passing the wrong argument for the builtin function. It supposed to be fnff instead of inii.

# define ALT_CI_NIOS_CUSTOM_INSTR_FLOATING_POINT_0(n,A, __builtin_custom_fnff(ALT_CI_NIOS_CUSTOM_INSTR_FLO ATING_POINT_0_N+(n&ALT_CI_NIOS_CUSTOM_INSTR_FLOATI NG_POINT_0_N_MASK),(A),()

If you update the system.h, it should remove the additional fixsfsi. Hopefully this works.