Re: [PATCH v2 2/4] target/loongarch: bstrins.w need set dest register EXT_SIGN

[Richard Henderson <richard.henderson@linaro.org>]

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On 9/29/22 00:27, gaosong wrote:
> 
> 在 2022/9/28 下午11:13, Richard Henderson 写道:
>> On 9/26/22 23:48, Song Gao wrote:
>>> Signed-off-by: Song Gao <gaosong@loongson.cn>
>>> ---
>>>   target/loongarch/insn_trans/trans_bit.c.inc | 4 ++--
>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/target/loongarch/insn_trans/trans_bit.c.inc 
>>> b/target/loongarch/insn_trans/trans_bit.c.inc
>>> index 9337714ec4..33e94878fd 100644
>>> --- a/target/loongarch/insn_trans/trans_bit.c.inc
>>> +++ b/target/loongarch/insn_trans/trans_bit.c.inc
>>> @@ -37,7 +37,7 @@ static bool gen_rr_ms_ls(DisasContext *ctx, arg_rr_ms_ls *a,
>>>                            DisasExtend src_ext, DisasExtend dst_ext,
>>>                             void (*func)(TCGv, TCGv, unsigned int, unsigned int))
>>>   {
>>> -    TCGv dest = gpr_dst(ctx, a->rd, dst_ext);
>>> +    TCGv dest = gpr_dst(ctx, a->rd, EXT_NONE);
>>>       TCGv src1 = gpr_src(ctx, a->rj, src_ext);
>>>         if (a->ls > a->ms) {
>>> @@ -206,7 +206,7 @@ TRANS(maskeqz, gen_rrr, EXT_NONE, EXT_NONE, EXT_NONE, gen_maskeqz)
>>>   TRANS(masknez, gen_rrr, EXT_NONE, EXT_NONE, EXT_NONE, gen_masknez)
>>>   TRANS(bytepick_w, gen_rrr_sa, EXT_NONE, EXT_NONE, gen_bytepick_w)
>>>   TRANS(bytepick_d, gen_rrr_sa, EXT_NONE, EXT_NONE, gen_bytepick_d)
>>> -TRANS(bstrins_w, gen_rr_ms_ls, EXT_NONE, EXT_NONE, gen_bstrins)
>>> +TRANS(bstrins_w, gen_rr_ms_ls, EXT_NONE, EXT_SIGN, gen_bstrins)
>>
>> These two hunks do opposite things: change dst_ext from NONE to SIGN, and then ignore 
>> the change.
>>
>> I assume the first hunk is in fact in error.
>>
> rd is also a src register,    rd should be src_dst.
> 
>      TCGv dest = gpr_src(ctx, a->rd, src_dst);   what about this?

Ah, I see the problem.  We're sharing a helper meant for unary operations for an 
instruction that is a binary operation with an in+out operand.

I suggest not attempting to share code between bstrins and bstrpick, like so.


r~

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diff --git a/target/loongarch/insn_trans/trans_bit.c.inc b/target/loongarch/insn_trans/trans_bit.c.inc
index 9337714ec4..b01e4aeb23 100644
--- a/target/loongarch/insn_trans/trans_bit.c.inc
+++ b/target/loongarch/insn_trans/trans_bit.c.inc
@@ -27,26 +27,34 @@ static void gen_bytepick_d(TCGv dest, TCGv src1, TCGv src2, target_long sa)
     tcg_gen_extract2_i64(dest, src1, src2, (64 - sa * 8));
 }
 
-static void gen_bstrins(TCGv dest, TCGv src1,
-                        unsigned int ls, unsigned int len)
+static bool gen_bstrins(DisasContext *ctx, arg_rr_ms_ls *a,
+                        DisasExtend dst_ext)
 {
-    tcg_gen_deposit_tl(dest, dest, src1, ls, len);
-}
-
-static bool gen_rr_ms_ls(DisasContext *ctx, arg_rr_ms_ls *a,
-                         DisasExtend src_ext, DisasExtend dst_ext,
-                         void (*func)(TCGv, TCGv, unsigned int, unsigned int))
-{
-    TCGv dest = gpr_dst(ctx, a->rd, dst_ext);
-    TCGv src1 = gpr_src(ctx, a->rj, src_ext);
+    TCGv src1 = gpr_src(ctx, a->rd, EXT_NONE);
+    TCGv src2 = gpr_src(ctx, a->rj, EXT_NONE);
+    TCGv dest = gpr_dst(ctx, a->rd, EXT_NONE);
 
     if (a->ls > a->ms) {
         return false;
     }
 
-    func(dest, src1, a->ls, a->ms - a->ls + 1);
+    tcg_gen_deposit_tl(dest, src1, src2, a->ls, a->ms - a->ls + 1);
     gen_set_gpr(a->rd, dest, dst_ext);
+    return true;
+}
 
+static bool gen_bstrpick(DisasContext *ctx, arg_rr_ms_ls *a,
+                         DisasExtend dst_ext)
+{
+    TCGv dest = gpr_dst(ctx, a->rd, EXT_NONE);
+    TCGv src1 = gpr_src(ctx, a->rj, EXT_NONE);
+
+    if (a->ls > a->ms) {
+        return false;
+    }
+
+    tcg_gen_extract_tl(dest, src1, a->ls, a->ms - a->ls + 1);
+    gen_set_gpr(a->rd, dest, dst_ext);
     return true;
 }
 
@@ -206,7 +214,7 @@ TRANS(maskeqz, gen_rrr, EXT_NONE, EXT_NONE, EXT_NONE, gen_maskeqz)
 TRANS(masknez, gen_rrr, EXT_NONE, EXT_NONE, EXT_NONE, gen_masknez)
 TRANS(bytepick_w, gen_rrr_sa, EXT_NONE, EXT_NONE, gen_bytepick_w)
 TRANS(bytepick_d, gen_rrr_sa, EXT_NONE, EXT_NONE, gen_bytepick_d)
-TRANS(bstrins_w, gen_rr_ms_ls, EXT_NONE, EXT_NONE, gen_bstrins)
-TRANS(bstrins_d, gen_rr_ms_ls, EXT_NONE, EXT_NONE, gen_bstrins)
-TRANS(bstrpick_w, gen_rr_ms_ls, EXT_NONE, EXT_SIGN, tcg_gen_extract_tl)
-TRANS(bstrpick_d, gen_rr_ms_ls, EXT_NONE, EXT_NONE, tcg_gen_extract_tl)
+TRANS(bstrins_w, gen_bstrins, EXT_SIGN)
+TRANS(bstrins_d, gen_bstrins, EXT_NONE)
+TRANS(bstrpick_w, gen_bstrpick, EXT_SIGN)
+TRANS(bstrpick_d, gen_bstrpick, EXT_NONE)