target/mips: Explode gen_msa_branch() as gen_msa_BxZ_V/BxZ()

In preparation of using the decodetree script, explode
gen_msa_branch() as following:

- OPC_BZ_V              -> BxZ_V(EQ)
- OPC_BNZ_V             -> BxZ_V(NE)
- OPC_BZ_[BHWD]         -> BxZ(false)
- OPC_BNZ_[BHWD]        -> BxZ(true)

Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20201208003702.4088927-10-f4bug@amsat.org>

target/mips/translate.c

@@ -28614,49 +28614,76 @@ static void gen_check_zero_element(TCGv tresult, uint8_t df, uint8_t wt)
     tcg_temp_free_i64(t1);
 }
-static void gen_msa_branch(DisasContext *ctx, uint32_t op1)
+static bool gen_msa_BxZ_V(DisasContext *ctx, int wt, int s16, TCGCond cond)
 {
-    uint8_t df = (ctx->opcode >> 21) & 0x3;
-    uint8_t wt = (ctx->opcode >> 16) & 0x1f;
-    int64_t s16 = (int16_t)ctx->opcode;
+    TCGv_i64 t0;
     check_msa_access(ctx);
     if (ctx->hflags & MIPS_HFLAG_BMASK) {
         gen_reserved_instruction(ctx);
-        return;
+        return true;
+    }
+    t0 = tcg_temp_new_i64();
+    tcg_gen_or_i64(t0, msa_wr_d[wt << 1], msa_wr_d[(wt << 1) + 1]);
+    tcg_gen_setcondi_i64(cond, t0, t0, 0);
+    tcg_gen_trunc_i64_tl(bcond, t0);
+    tcg_temp_free_i64(t0);
+
+    ctx->btarget = ctx->base.pc_next + (s16 << 2) + 4;
+
+    ctx->hflags |= MIPS_HFLAG_BC;
+    ctx->hflags |= MIPS_HFLAG_BDS32;
+
+    return true;
+}
+
+static bool gen_msa_BxZ(DisasContext *ctx, int df, int wt, int s16, bool if_not)
+{
+    check_msa_access(ctx);
+
+    if (ctx->hflags & MIPS_HFLAG_BMASK) {
+        gen_reserved_instruction(ctx);
+        return true;
     }
+
+    gen_check_zero_element(bcond, df, wt);
+    if (if_not) {
+        tcg_gen_setcondi_tl(TCG_COND_EQ, bcond, bcond, 0);
+    }
+
+    ctx->btarget = ctx->base.pc_next + (s16 << 2) + 4;
+    ctx->hflags |= MIPS_HFLAG_BC;
+    ctx->hflags |= MIPS_HFLAG_BDS32;
+
+    return true;
+}
+
+static void gen_msa_branch(DisasContext *ctx, uint32_t op1)
+{
+    uint8_t df = (ctx->opcode >> 21) & 0x3;
+    uint8_t wt = (ctx->opcode >> 16) & 0x1f;
+    int64_t s16 = (int16_t)ctx->opcode;
+
     switch (op1) {
     case OPC_BZ_V:
     case OPC_BNZ_V:
-        {
-            TCGv_i64 t0 = tcg_temp_new_i64();
-            tcg_gen_or_i64(t0, msa_wr_d[wt << 1], msa_wr_d[(wt << 1) + 1]);
-            tcg_gen_setcondi_i64((op1 == OPC_BZ_V) ?
-                    TCG_COND_EQ : TCG_COND_NE, t0, t0, 0);
-            tcg_gen_trunc_i64_tl(bcond, t0);
-            tcg_temp_free_i64(t0);
-        }
+        gen_msa_BxZ_V(ctx, wt, s16, (op1 == OPC_BZ_V) ?
+                                    TCG_COND_EQ : TCG_COND_NE);
         break;
     case OPC_BZ_B:
     case OPC_BZ_H:
     case OPC_BZ_W:
     case OPC_BZ_D:
-        gen_check_zero_element(bcond, df, wt);
+        gen_msa_BxZ(ctx, df, wt, s16, false);
         break;
     case OPC_BNZ_B:
     case OPC_BNZ_H:
     case OPC_BNZ_W:
     case OPC_BNZ_D:
-        gen_check_zero_element(bcond, df, wt);
-        tcg_gen_setcondi_tl(TCG_COND_EQ, bcond, bcond, 0);
+        gen_msa_BxZ(ctx, df, wt, s16, true);
         break;
     }
-
-    ctx->btarget = ctx->base.pc_next + (s16 << 2) + 4;
-
-    ctx->hflags |= MIPS_HFLAG_BC;
-    ctx->hflags |= MIPS_HFLAG_BDS32;
 }
 static void gen_msa_i8(DisasContext *ctx)