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Re: [Qemu-devel] [PATCH v2 1/4] target/mips: Fix emulation of ILVEV.<B|H
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/4] target/mips: Fix emulation of ILVEV.<B|H|W> on big endian host |
Date: |
Wed, 26 Jun 2019 18:02:14 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 |
On 6/20/19 3:45 PM, Aleksandar Markovic wrote:
> From: Aleksandar Markovic <address@hidden>
>
> Fix emulation of ILVEV.<B|H|W> on big endian host by applying
> mapping of data element indexes from one endian to another.
>
> Signed-off-by: Aleksandar Markovic <address@hidden>
> Reviewed-by: Aleksandar Rikalo <address@hidden>
> ---
> target/mips/msa_helper.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/target/mips/msa_helper.c b/target/mips/msa_helper.c
> index be059a3..215d8af 100644
> --- a/target/mips/msa_helper.c
> +++ b/target/mips/msa_helper.c
> @@ -1737,6 +1737,24 @@ void helper_msa_ilvev_df(CPUMIPSState *env, uint32_t
> df, uint32_t wd,
>
> switch (df) {
> case DF_BYTE:
> +#if defined(TARGET_WORDS_BIGENDIAN)
The commit message talks about the endianness of the host, whereas this check
is for the endianness of the target.
> + pwd->b[8] = pws->b[9];
> + pwd->b[9] = pwt->b[9];
> + pwd->b[10] = pws->b[11];
> + pwd->b[11] = pwt->b[11];
> + pwd->b[12] = pws->b[13];
> + pwd->b[13] = pwt->b[13];
> + pwd->b[14] = pws->b[15];
> + pwd->b[15] = pwt->b[15];
> + pwd->b[0] = pws->b[1];
> + pwd->b[1] = pwt->b[1];
> + pwd->b[2] = pws->b[3];
> + pwd->b[3] = pwt->b[3];
> + pwd->b[4] = pws->b[5];
> + pwd->b[5] = pwt->b[5];
> + pwd->b[6] = pws->b[7];
> + pwd->b[7] = pwt->b[7];
> +#else
> pwd->b[15] = pws->b[14];
> pwd->b[14] = pwt->b[14];
> pwd->b[13] = pws->b[12];
FWIW, avoiding this sort of duplication is why other targets define helper
macros like
PPC:
#define VsrB(i) u8[15 - (i)]
etc
ARM, S390:
/* Note that vector data is stored in host-endian 64-bit chunks,
so addressing units smaller than that needs a host-endian fixup. */
#ifdef HOST_WORDS_BIGENDIAN
#define H1(x) ((x) ^ 7)
etc
r~