My understanding is that software floating point library should be used in case if there is no hardware FPU or it's unknown whether it's there. (v8_can_use_fpu_instructions != v8_use_mips_abi_hardfloat) doesn't make sense to me. Executing code containing FPU instructions (v8_can_use_fpu_instructions = true), will fail if there is no FPU (implied by v8_use_mips_abi_hardfloat = false). Please correct me if I am wrong.