Re: [RFC v2 4/6] target/mips: Add native library calls

[Richard Henderson <richard.henderson@linaro.org>]

On 6/7/23 09:47, Yeqi Fu wrote:
> +void helper_native_memcpy(CPUMIPSState *env)
> +{
> +    CPUState *cs = env_cpu(env);
> +    NATIVE_FN_W_3W();
> +    void *ret;
> +    void *dest = g2h(cs, arg0);
> +    void *src = g2h(cs, arg1);
> +    size_t n = (size_t)arg2;
> +    ret = memcpy(dest, src, n);
> +    env->active_tc.gpr[2] = (target_ulong)h2g(ret);
> +}

I would expect everything except for the guest ABI to be handled by common code, so that 
you do not have N copies of every native emulated function.  This needs to be something like

abi_ptr do_native_memcpy(CPUArchState *env, abi_ptr dst, abi_ptr src,
                          abi_ptr len, uintptr_t ra);

void helper_native_memcpy(CPUMIPSState *env)
{
     env->active_tc.gpr[2] =
         do_native_memcpy(env, env->active_tc.gpr[4],
                          env->active_tc.gpr[5],
                          env->active_tc.gpr[6], GETPC());
}

Even better, provide some guest abstraction akin to va_start/va_arg so that all of the 
per-native function code becomes shared.


r~