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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH 11/18] tcg/arm: add bswap ops
Date: Fri, 9 Apr 2010 00:32:04 +0100
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Cc: Andrzej Zaborowski <balrog@zabor.org>, Aurelien Jarno <aurelien@aurel32.net>

> +static inline void tcg_out_bswap32(TCGContext *s, int cond, int rd, int rn)
> +#else
> +    /* This code only uses one temporary register. There is probably
> +       a faster way to do that with more temporary registers. */

You can do better even without a temporary:

  eor	r8, rn, rn, ror #16
  bic	r8, r8, #0x00ff0000
  mov	 rd, rn, ror #8
  eor	rd, rd, r8, lsr #8

Paul