Function use_thumb_mode

build.rs:205–208

()

}

fn use_thumb_mode() -> bool {
    // In thumb mode, r7 is reserved.
    !can_compile("pub unsafe fn f() { core::arch::asm!(\"udf #16\", in(\"r7\") 0); }")
}

fn has_lower_upper_exp_for_non_zero() -> bool {
    // LowerExp/UpperExp for NonZero* were added in Rust 1.84.