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Re: [Qemu-arm] [PATCH 11/42] target/arm: Add helpers for VFP register lo

From: Richard Henderson
Subject: Re: [Qemu-arm] [PATCH 11/42] target/arm: Add helpers for VFP register loads and stores
Date: Fri, 7 Jun 2019 12:11:55 -0500
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0

On 6/6/19 12:45 PM, Peter Maydell wrote:
> The current VFP code has two different idioms for
> loading and storing from the VFP register file:
>  1 using the gen_mov_F0_vreg() and similar functions,
>    which load and store to a fixed set of TCG globals
>    cpu_F0s, CPU_F0d, etc
>  2 by direct calls to tcg_gen_ld_f64() and friends
> We want to phase out idiom 1 (because the use of the
> fixed globals is a relic of a much older version of TCG),
> but idiom 2 is quite longwinded:
>  tcg_gen_ld_f64(tmp, cpu_env, vfp_reg_offset(true, reg))
> requires us to specify the 64-bitness twice, once in
> the function name and once by passing 'true' to
> vfp_reg_offset(). There's no guard against accidentally
> passing the wrong flag.
> Instead, let's move to a convention of accessing 64-bit
> registers via the existing neon_load_reg64() and
> neon_store_reg64(), and provide new neon_load_reg32()
> and neon_store_reg32() for the 32-bit equivalents.
> Implement the new functions and use them in the code in
> translate-vfp.inc.c. We will convert the rest of the VFP
> code as we do the decodetree conversion in subsequent
> commits.
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  target/arm/translate-vfp.inc.c | 40 +++++++++++++++++-----------------
>  target/arm/translate.c         | 10 +++++++++
>  2 files changed, 30 insertions(+), 20 deletions(-)

Reviewed-by: Richard Henderson <address@hidden>


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