Subject: Re: [PATCH] powerpc: provide __bswapdi2

From: Michael Neuling <[email-masked]>
Date: Mon, 13 May 2013 17:09:59 +1000

David Woodhouse <[email-masked]> wrote:

> From: David Woodhouse <[email-masked]>
> 
> Some versions of GCC apparently expect this to be provided by libgcc.
> 
> Signed-off-by: David Woodhouse <[email-masked]>
> ---
> Untested.
> 
> diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
> index 19e096b..f077dc2 100644
> --- a/arch/powerpc/kernel/misc_32.S
> +++ b/arch/powerpc/kernel/misc_32.S
> @@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
>  	li	r3,2
>  	blr
>  
> +_GLOBAL(__bswapdi2)
> +	rlwinm	10,4,8,0xffffffff
> +	rlwinm	11,3,8,0xffffffff
> +	rlwimi	10,4,24,0,7
> +	rlwimi	11,3,24,0,7
> +	rlwimi	10,4,24,16,23
> +	rlwimi	11,3,24,16,23
> +	mr	4,11
> +	mr	3,10
> +	blr
> +

This doesn't work for me but the below does:

_GLOBAL(__bswapdi2)
	rotlwi  r9,r4,8
	rotlwi  r10,r3,8
	rlwimi  r9,r4,24,0,7
	rlwimi  r10,r3,24,0,7
	rlwimi  r9,r4,24,16,23
	rlwimi  r10,r3,24,16,23
	mr      r4,r10
	mr      r3,r9
	blr

stolen from GCC -02 output of:
  unsigned long long __bswapdi2(unsigned long long x)
  {
	 return ((x & 0x00000000000000ffULL) << 56) |
		((x & 0x000000000000ff00ULL) << 40) |
		((x & 0x0000000000ff0000ULL) << 24) |
		((x & 0x00000000ff000000ULL) <<  8) |
		((x & 0x000000ff00000000ULL) >>  8) |
		((x & 0x0000ff0000000000ULL) >> 24) |
		((x & 0x00ff000000000000ULL) >> 40) |
		((x & 0xff00000000000000ULL) >> 56);
  }

>  _GLOBAL(abs)
>  	srawi	r4,r3,31
>  	xor	r3,r3,r4
> diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
> index 5cfa800..3b2e6e8 100644
> --- a/arch/powerpc/kernel/misc_64.S
> +++ b/arch/powerpc/kernel/misc_64.S
> @@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
>  	isync
>  	blr
>  
> +_GLOBAL(__bswapdi2)
> +	srdi	8,3,32
> +	rlwinm	7,3,8,0xffffffff
> +	rlwimi	7,3,24,0,7
> +	rlwinm	9,8,8,0xffffffff
> +	rlwimi	7,3,24,16,23
> +	rlwimi	9,8,24,0,7
> +	rlwimi	9,8,24,16,23
> +	sldi	7,7,32
> +	or	7,7,9
> +	mr	3,7
> +	blr

This works but we should add "r" to the register names.

I'll repost

Mikey

>  
>  #if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
>  /*
> diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
> index 78b8766..c296665 100644
> --- a/arch/powerpc/kernel/ppc_ksyms.c
> +++ b/arch/powerpc/kernel/ppc_ksyms.c
> @@ -143,7 +143,8 @@ EXPORT_SYMBOL(__lshrdi3);
>  int __ucmpdi2(unsigned long long, unsigned long long);
>  EXPORT_SYMBOL(__ucmpdi2);
>  #endif
> -
> +long long __bswapdi2(long long);
> +EXPORT_SYMBOL(__bswapdi2);
>  EXPORT_SYMBOL(memcpy);
>  EXPORT_SYMBOL(memset);
>  EXPORT_SYMBOL(memmove);
> 
> -- 
> dwmw2
> 
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