Re: [Qemu-devel] [PATCH] tci: Add implementation of rotl_i64, rotr_i64

[Jay Foad]

> diff --git a/tci.c b/tci.c
> index 18c888e..94b7851 100644
> --- a/tci.c
> +++ b/tci.c
> @@ -952,8 +952,16 @@ uintptr_t tcg_qemu_tb_exec(CPUArchState *env, uint8_t 
> *tb_ptr)
>              break;
>  #if TCG_TARGET_HAS_rot_i64
>          case INDEX_op_rotl_i64:
> +            t0 = *tb_ptr++;
> +            t1 = tci_read_ri64(&tb_ptr);
> +            t2 = tci_read_ri64(&tb_ptr);
> +            tci_write_reg64(t0, (t1 << t2) | (t1 >> (64 - t2)));
> +            break;
>          case INDEX_op_rotr_i64:
> -            TODO();
> +            t0 = *tb_ptr++;
> +            t1 = tci_read_ri64(&tb_ptr);
> +            t2 = tci_read_ri64(&tb_ptr);
> +            tci_write_reg64(t0, (t1 >> t2) | (t1 << (64 - t2)));

<< (64 - t2) is undefined behaviour in C when t2 is 0. How about << (-t2 & 63) ?

Jay.