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Re: [Qemu-devel] [PATCH][ppc] reorganize register set for SPE + TCG
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH][ppc] reorganize register set for SPE + TCG |
Date: |
Wed, 15 Oct 2008 18:11:30 +0200 |
User-agent: |
Mozilla-Thunderbird 2.0.0.16 (X11/20080724) |
Nathan Froyd a écrit :
> The (large, invasive) patch below is a preparation patch for converting
> (most) SPE instructions to use TCG. The rationale is that your ordinary
> SPE instruction deals with three 64-bit quantaties (and a potential
> 64-bit accumulator). In the current implementation, it's extremely
> laborious/difficult to pass those 64-bit quantaties to helpers, since
> the high/low words for SPE registers are not contiguous in the
> environment. (TCG helpers for SPE instructions are not yet implemented,
> but they will be necessary as part of the total conversion to TCG.)
You can pass 64-bit TCG registers to helpers. And you can create one TCG
64-bit value from two 32-bits value if needed, and split it back later.
This is exactly what is already done with load_gpr64() and store_gpr64().
Then the limit on the number of arguments of TCG helpers is not a
problem anymore.
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
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