Re: [PATCH v1 1/7] arm64: introduce basic aarch64 instruction decodinghelpers

From: Christopher Covington
Date: Wed Sep 25 2013 - 08:59:06 EST


Hi Jiang,

On 09/25/2013 06:44 AM, Jiang Liu wrote:

[...]

> diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c

[...]

> +static int aarch64_insn_cls[] = {
> + AARCH64_INSN_CLS_UNKNOWN, /* 0 0 X X */
> + AARCH64_INSN_CLS_UNKNOWN, /* 0 0 X X */
> + AARCH64_INSN_CLS_UNKNOWN, /* 0 0 X X */
> + AARCH64_INSN_CLS_UNKNOWN, /* 0 0 X X */
> + AARCH64_INSN_CLS_LDST, /* X 1 X 0 */
> + AARCH64_INSN_CLS_DP_REG, /* X 1 0 1 */
> + AARCH64_INSN_CLS_LDST, /* X 1 X 0 */
> + AARCH64_INSN_CLS_DP_FPSIMD, /* 0 1 1 1 */
> + AARCH64_INSN_CLS_DP_IMM, /* 1 0 0 X */
> + AARCH64_INSN_CLS_DP_IMM, /* 1 0 0 X */
> + AARCH64_INSN_CLS_BR_SYS, /* 1 0 1 X */
> + AARCH64_INSN_CLS_BR_SYS, /* 1 0 1 X */
> + AARCH64_INSN_CLS_LDST, /* X 1 X 0 */
> + AARCH64_INSN_CLS_DP_REG, /* X 1 0 1 */
> + AARCH64_INSN_CLS_LDST, /* X 1 X 0 */
> + AARCH64_INSN_CLS_DP_FPSIMD, /* 1 1 1 1 */
> +};

As I read this, I was initially puzzled as to why there are duplicate entries
in the list. Since the data structure doesn't really support don't-cares,
perhaps it would be clearer to use 1's and 0's instead of X's.

[...]

Thanks,
Christopher

--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/