crosstool-ng.github.io | This is work-in-progress | Static Site Generator library

TL;DR: How is 0x400921f4 the IEEE 754 representation of 3.1415801? Is this a soft-float somehow? What am I missing?

I am currently in the process of getting to know crosstool-NG while building my own cross-compiler for the Raspberry Pi 3 and Raspberry Pi Zero W. (*1)

After reading documentation spread over their forums and wikis, I understood that the RPi3 and RPi0 compilers need to target different ARM architectures, ARMv7 and ARMv6 respectively. However, both SoCs have a floating-point unit, so I want to use hard floating point to match the rest of the Raspberry Pi libraries.

I tested my newly-built armv6-rpi-linux-gnueabi-gcc 6.4.0 against the arm-linux-gnueabihf-gcc 4.9.3 available at the RaspberryPi Tool repository. I read up how to determine if an executable uses hard fp here. Sure enough, when I compile the following minimal test case.

I compile using gcc -O0 -o main main.c with both compilers. In the following: main.rpi for my toolchain, main.hf for pre-built toolchain.

I am developing a Net-SNMP subagent whose final target will be an ARM board, so I'm using CMake to make it easier to manage building the native and cross-compiled versions. I started testing it on my host platform (x86_64) and it builds and works fine with this CMakeLists.txt file: