Nios II Embedded Design Suite Release Notes

ID 683228
Date 6/17/2015
Document Table of Contents

1.5.2. Enhanced Floating Point Custom Instruction Support

In v13.1, Qsys adds an option to select a new floating point custom instruction set component, Floating Point Hardware 2.

To take advantage of software support for the Floating Point Hardware 2 instructions, include altera_nios_custom_instr_floating_point_2.h , which forces GCC to call newlib math functions (rather than GCC built-in math functions). Intel recommends that you recompile newlib with for optimum performance.

Note: Do not use the –mcustom -fpu-cfg command-line option for GCC. This option does not support the Floating Point Hardware 2 instructions.

The Nios II software build tools (SBT) add individual –mcustom commands to the makefile to support the Floating Point Hardware 2 custom instructions.