Re: [Qemu-riscv] [Qemu-devel] [RFC v1 05/23] riscv: Add the tcg-target header file

[Richard Henderson]

On 11/15/18 11:34 PM, Alistair Francis wrote:
> +#define TCG_TARGET_HAS_extrl_i64_i32    0
> +#define TCG_TARGET_HAS_extrh_i64_i32    0

You need these two for rv64 to preserve the invariant that 32-bit values are
sign-extended in a 64-bit register.  Otherwise _i32 comparisons won't work
reliably.

The first is yet another alias for exts32_i64; the second is an arithmetic
right shift of 32.  Their existence changes how code is emitted in tcg-op.c.


r~