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Re: [Qemu-devel] [PATCH v7 2/2] Add optionrom compatible with fw_cfg DMA
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-devel] [PATCH v7 2/2] Add optionrom compatible with fw_cfg DMA version |
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Date: |
Wed, 11 May 2016 22:07:27 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1 |
On 11/05/2016 19:42, Richard W.M. Jones wrote:
> +
> +#ifdef __clang__
> +#define ADDR32
> +#else
> +#define ADDR32 "addr32 "
> +#endif
> +
> +static inline uint16_t readw_es(uint16_t offset)
> +{
> + uint16_t val;
> + asm(ADDR32"movw %%es:(%1), %0" : "=r"(val) : "r"((uint32_t)offset));
> + barrier();
> + return val;
> +}
Please check that the output is the same byte-by-byte for this asm.
I guess this is okay if we have a guarantee from clang that the asm
block stays at the beginning. Perhaps check for the 0x55 0xaa signature
in signrom.py?
Thanks,
Paolo