Floating point support

▶ Some processors have a floating point unit, some others do not. ▶ For example, many ARMv4 and ARMv5 CPUs do not have a floating point unit. Since ARMv7, a VFP unit is mandatory. ▶ For processors having a floating point unit, the toolchain should generate hard float code, in order to use the floating point instructions directly ▶ For processors without a floating point unit, two solutions ▶ Generate hard float code and rely on the kernel to emulate the floating point instructions. This is very slow. ▶ Generate soft float code, so that instead of generating floating point instructions, calls to a user space library are generated ▶ Decision taken at toolchain configuration time ▶ Also possible to configure which floating point unit should be used