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* [Qemu-devel] [SH4] Fix swap.b
@ 2008-10-12 15:21 Vladimir Prus
  2008-10-12 23:31 ` Aurelien Jarno
  0 siblings, 1 reply; 2+ messages in thread
From: Vladimir Prus @ 2008-10-12 15:21 UTC (permalink / raw)
  To: qemu-devel

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The SH4 manual documents the swap.b instruction as follows:

	SWAP.B Rm,Rn
		Rm → swap lower 2 bytes → Rn

Current QEMU code, in addition to the above, also clears the high
16 bits. The immediate breakage I saw is that htonl function applied 
to  netmask of 255.255.255.0 gives 0, which breaks all networking.
Attached patch fixes the problem.

- Volodya

---
 target-sh4/translate.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/target-sh4/translate.c b/target-sh4/translate.c
index 365936f..2ef8c00 100644
--- a/target-sh4/translate.c
+++ b/target-sh4/translate.c
@@ -686,7 +686,9 @@ void _decode_opc(DisasContext * ctx)
 	return;
     case 0x6008:		/* swap.b Rm,Rn */
 	{
-	    TCGv high, low;
+	    TCGv highw, high, low;
+	    highw = tcg_temp_new(TCG_TYPE_I32);
+	    tcg_gen_andi_i32(highw, REG(B7_4), 0xffff0000);
 	    high = tcg_temp_new(TCG_TYPE_I32);
 	    tcg_gen_ext8u_i32(high, REG(B7_4));
 	    tcg_gen_shli_i32(high, high, 8);
@@ -694,6 +696,7 @@ void _decode_opc(DisasContext * ctx)
 	    tcg_gen_shri_i32(low, REG(B7_4), 8);
 	    tcg_gen_ext8u_i32(low, low);
 	    tcg_gen_or_i32(REG(B11_8), high, low);
+	    tcg_gen_or_i32(REG(B11_8), REG(B11_8), highw);
 	    tcg_temp_free(low);
 	    tcg_temp_free(high);
 	}
-- 
1.5.3.5

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [Qemu-devel] [SH4] Fix swap.b
  2008-10-12 15:21 [Qemu-devel] [SH4] Fix swap.b Vladimir Prus
@ 2008-10-12 23:31 ` Aurelien Jarno
  0 siblings, 0 replies; 2+ messages in thread
From: Aurelien Jarno @ 2008-10-12 23:31 UTC (permalink / raw)
  To: qemu-devel

On Sun, Oct 12, 2008 at 07:21:05PM +0400, Vladimir Prus wrote:
> 
> The SH4 manual documents the swap.b instruction as follows:
> 
> 	SWAP.B Rm,Rn
> 		Rm → swap lower 2 bytes → Rn
> 
> Current QEMU code, in addition to the above, also clears the high
> 16 bits. The immediate breakage I saw is that htonl function applied 
> to  netmask of 255.255.255.0 gives 0, which breaks all networking.
> Attached patch fixes the problem.
> 

Thanks, applied.

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net

^ permalink raw reply	[flat|nested] 2+ messages in thread

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