[Qemu-devel] [SH4] Fix swap.b

[Vladimir Prus <vladimir@codesourcery.com>]

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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