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

[Vladimir Prus]

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