Subject: [PATCH v1 1/7] arm64: introduce basic aarch64 instruction decoding helpers

From: [email-masked] (Christopher Covington)
Date: Wed, 25 Sep 2013 08:58:55 -0400

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

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