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References: <524D3FAF.7020701@linaro.org>
From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
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Date: Thu, 03 Oct 2013 12:31:37 +0100
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Subject: Re: [Qemu-devel] [PATCH] target-arm: Implement ARMv8 VSEL
	instruction.
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To: Will Newton <will.newton@linaro.org>
Cc: qemu-devel@nongnu.org, patches@linaro.org


will.newton@linaro.org writes:

<snip>
> @@ -6756,6 +6864,13 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
>                  goto illegal_op;
>              return;
>          }
> +	if ((insn & 0x0f800e50) == 0x0e000a00) {
> +	    /* ARMv8 VFP.  */
> +	    ARCH(8);
> +
> +	    if (disas_v8vfp_insn(env, s, insn))
> +		goto illegal_op;
> +	}
>          if (((insn & 0x0f30f000) == 0x0510f000) ||
>              ((insn & 0x0f30f010) == 0x0710f000)) {
>              if ((insn & (1 << 22)) == 0) {
> @@ -8768,6 +8883,12 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
>              insn = (insn & 0xe2ffffff) | ((insn & (1 << 28)) >> 4) | (1 << 28);
>              if (disas_neon_data_insn(env, s, insn))
>                  goto illegal_op;
> +	} else if ((insn & 0x0f800e50) == 0x0e000a00) {
> +	    /* ARMv8 VFP.  */
> +	    ARCH(8);
> +
> +	    if (disas_v8vfp_insn(env, s, insn))
> +		goto illegal_op;
>          } else {
>              if (insn & (1 << 28))
>                  goto illegal_op;

I wonder is there a better way to deal with these masks for checking
instruction type? I only mention it because the same constant is used
twice and should it ever be changed there is a risk of one being missed
(although conceivably thumb encoding could be different?).

I appreciate the disassembler code is already a mass of magic constants
so it's not a major thing for me.

Cheers,


-- 
Alex Bennée