4 // RCX on Windows, RDI elsewhere
14 // ARG0 is the register in which the first argument goes.
15 // Naturally this depends on your operating system.
16 # define RUSTRT_ARG0_S r0
17 # define RUSTRT_ARG1_S r1
18 # define RUSTRT_ARG2_S r2
19 # define RUSTRT_ARG3_S r3