On 8/26/26 15:50, Amit Machhiwal wrote:
On 2026/08/26 10:38 AM, Chinmay Rath wrote:
From: Nikhil Kumar Singh <[email protected]>

Convert cache management instructions to decodetree using custom
X-form layouts (@X_ea, @X_l, @X_th) and dedicated translation functions.
This ensures reserved bits are accurately represented and ignored by
the decoder (using '-' in the patterns), rather than being erroneously
parsed into instruction fields.

Legacy GEN_HANDLER-based implementations are removed.

The implementation preserves legacy semantics, including:
   - MMU-visible accesses for instructions treated as loads
     (e.g. dcbt, dcbtst, dcbtep, dcbtstep)
   - Supervisor and BookE-specific constraints
   - Effective address computation via do_ea_calc()

Instructions that were defined as no-ops in the legacy implementation
remain no-ops here.

Note on intentional behavior changes:
   - dcbf now validates the L field against the Power ISA v3.1 set of
     legal values (0, 1, 3, 4, 6).
   - Reserved bits that were previously encoded as part of the opcode
     mask (and trapped if set) are now properly decoded as "don't care"
     ('-' in the pattern).

Testing:
   - Verified TCG equivalence for all cache operations

Signed-off-by: Nikhil Kumar Singh <[email protected]>
Tested-by: Tasmiya Nalatwad <[email protected]>
Reviewed-by: Glenn Miles <[email protected]>
Signed-off-by: Chinmay Rath <[email protected]>
---
  target/ppc/helper.h      |   8 +-
  target/ppc/insn32.decode |  35 +++
  target/ppc/mem_helper.c  |   8 +-
  target/ppc/translate.c   | 478 ++++++++++++++++++++-------------------
  4 files changed, 292 insertions(+), 237 deletions(-)

diff --git a/target/ppc/helper.h b/target/ppc/helper.h
index 6b2d19a3ad..46ad78d1d4 100644
--- a/target/ppc/helper.h
+++ b/target/ppc/helper.h
@@ -48,12 +48,12 @@ DEF_HELPER_FLAGS_3(stmw, TCG_CALL_NO_WG, void, env, tl, i32)
  DEF_HELPER_4(lsw, void, env, tl, i32, i32)
  DEF_HELPER_5(lswx, void, env, tl, i32, i32, i32)
  DEF_HELPER_FLAGS_4(stsw, TCG_CALL_NO_WG, void, env, tl, i32, i32)
-DEF_HELPER_FLAGS_3(dcbz, TCG_CALL_NO_WG, void, env, tl, int)
+DEF_HELPER_FLAGS_3(DCBZ, TCG_CALL_NO_WG, void, env, tl, int)
  #ifdef TARGET_PPC64
-DEF_HELPER_FLAGS_2(dcbzl, TCG_CALL_NO_WG, void, env, tl)
+DEF_HELPER_FLAGS_2(DCBZL, TCG_CALL_NO_WG, void, env, tl)
  #endif
-DEF_HELPER_FLAGS_2(icbi, TCG_CALL_NO_WG, void, env, tl)
-DEF_HELPER_FLAGS_2(icbiep, TCG_CALL_NO_WG, void, env, tl)
+DEF_HELPER_FLAGS_2(ICBI, TCG_CALL_NO_WG, void, env, tl)
+DEF_HELPER_FLAGS_2(ICBIEP, TCG_CALL_NO_WG, void, env, tl)
#if defined(TARGET_PPC64)
  DEF_HELPER_4(DIVDEU, i64, env, i64, i64, i32)
diff --git a/target/ppc/insn32.decode b/target/ppc/insn32.decode
index 26948e08a7..6b1cf9a0a9 100644
--- a/target/ppc/insn32.decode
+++ b/target/ppc/insn32.decode
@@ -1306,6 +1306,41 @@ XVF64GERPN      111011 ... -- .... 0 ..... 10111010 ..-  
@XX3_at xa=%xx_xa_pair
  XVF64GERNP      111011 ... -- .... 0 ..... 01111010 ..-  @XX3_at 
xa=%xx_xa_pair
  XVF64GERNN      111011 ... -- .... 0 ..... 11111010 ..-  @XX3_at 
xa=%xx_xa_pair
+## Cache Management Instructions
+
+&X_ea           ra rb
+@X_ea           ...... ..... ra:5 rb:5 .......... .     &X_ea
+
+&X_l            l ra rb
+@X_l            ...... .. l:3 ra:5 rb:5 .......... .    &X_l
+
+&X_th           th ra rb
+@X_th           ...... th:5 ra:5 rb:5 .......... .      &X_th
+
+DCBF            011111 -- ... ..... ..... 0001010110 -   @X_l
+DCBFEP          011111 ----- ..... ..... 0001111111 -   @X_ea
+DCBI            011111 ----- ..... ..... 0111010110 -   @X_ea
+DCBST           011111 ----- ..... ..... 0000110110 -   @X_ea
+DCBSTEP         011111 ----- ..... ..... 0000111111 -   @X_ea
+DCBA            011111 ----- ..... ..... 1011110110 -   @X_ea
+
+DCBT            011111 ..... ..... ..... 0100010110 -   @X_th
+DCBTEP          011111 ----- ..... ..... 0100111111 -   @X_ea
+DCBTST          011111 ..... ..... ..... 0011110110 -   @X_th
+DCBTSTEP        011111 ----- ..... ..... 0011111111 -   @X_ea
+
+DCBTLS          011111 ..... ..... ..... 0010100110 -   @X_th
+DCBLC           011111 ..... ..... ..... 0110000110 -   @X_th
+
+DCBZ            011111 ----- ..... ..... 1111110110 -   @X_ea
+DCBZEP          011111 ----- ..... ..... 1111111111 -   @X_ea
+ICBI            011111 ----- ..... ..... 1111010110 -   @X_ea
+ICBIEP          011111 ----- ..... ..... 1111011111 -   @X_ea
+
+DST             011111 ----- ..... ..... 0101010110 -   @X_ea
+DSTST           011111 ----- ..... ..... 0101110110 -   @X_ea
Per **PowerISA v3.1 §4.3.2.1**, dst, dstst, and dss are obsolete and
must be treated as no-ops independent of whether Vector instructions are
available. The new REQUIRE_INSNS_FLAGS(ctx, ALTIVEC) guard in all three
handlers is incorrect — it causes these opcodes to be treated as illegal
instructions on non-Altivec CPUs, contradicting the ISA mandate. These
handlers should unconditionally return true with no flag check, matching
the ISA's "always a no-op" requirement. The ra == 0 INVAL check in
trans_DST and trans_DSTST should also be dropped for the same reason —
if the instruction is a no-op, the operand constraint has no effect.
Thanks Amit !
This is very informative. There are many such instances in QEMU code where insns haven't been updated as per the newer ISA. Though, I'd like to point out that the REQUIRE_INSNS_FLAGS(ctx, ALTIVEC) guard in those insns is not new. This was already present as in the code, I will mark it with [A] below for reference. This patch simply intends to move the insn to decodetree keeping the existing logic intact. The translation logic and flag checks remain same for these 3 pointed out insns. I'd like to take up your suggestion here and post a folllow-up patch to update those insns as per the new ISA. Would that be okay ? Or would you prefer the insn's correction as per the ISA in this same decodetree movement patch ?

+DSS             011111 ----- ..... ..... 1100110110 -   @X_ea
+
  ##Extend Sign Word and Shift Left Immediate XS-form
  EXTSWSLI         011111 ..... ..... ..... 110111101 . .         @XS
diff --git a/target/ppc/mem_helper.c b/target/ppc/mem_helper.c
index 787ba2cdec..95a224e74c 100644
--- a/target/ppc/mem_helper.c
+++ b/target/ppc/mem_helper.c
@@ -319,13 +319,13 @@ static void dcbz_common(CPUPPCState *env, target_ulong 
addr,
      clear_helper_retaddr();
  }
-void helper_dcbz(CPUPPCState *env, target_ulong addr, int mmu_idx)
+void helper_DCBZ(CPUPPCState *env, target_ulong addr, int mmu_idx)
  {
      dcbz_common(env, addr, mmu_idx, env->dcache_line_size, GETPC());
  }
#ifdef TARGET_PPC64
-void helper_dcbzl(CPUPPCState *env, target_ulong addr)
+void helper_DCBZL(CPUPPCState *env, target_ulong addr)
  {
      int dcbz_size = env->dcache_line_size;
@@ -341,7 +341,7 @@ void helper_dcbzl(CPUPPCState *env, target_ulong addr)
  }
  #endif
-void helper_icbi(CPUPPCState *env, target_ulong addr)
+void helper_ICBI(CPUPPCState *env, target_ulong addr)
  {
      unsigned mmu_idx = cpu_mmu_index(env_cpu(env), false);
      MemOpIdx oi = make_memop_idx(MO_UL | MO_UNALN, mmu_idx);
@@ -357,7 +357,7 @@ void helper_icbi(CPUPPCState *env, target_ulong addr)
      cpu_ldl_mmu(env, addr, oi, GETPC());
  }
-void helper_icbiep(CPUPPCState *env, target_ulong addr)
+void helper_ICBIEP(CPUPPCState *env, target_ulong addr)
  {
  #if !defined(CONFIG_USER_ONLY)
      MemOpIdx oi = make_memop_idx(MO_UL | MO_UNALN, PPC_TLB_EPID_LOAD);
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index cc9287dcc5..60c88a6153 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -4296,216 +4296,6 @@ static void gen_setb(DisasContext *ctx)
  }
  #endif
-/*** Cache management ***/
-
-/* dcbf */
-static void gen_dcbf(DisasContext *ctx)
-{
-    /* XXX: specification says this is treated as a load by the MMU */
-    TCGv t0;
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    t0 = tcg_temp_new();
-    gen_addr_reg_index(ctx, t0);
-    gen_qemu_ld8u(ctx, t0, t0);
-}
-
-/* dcbfep (external PID dcbf) */
-static void gen_dcbfep(DisasContext *ctx)
-{
-    /* XXX: specification says this is treated as a load by the MMU */
-    TCGv t0;
-    CHK_SV(ctx);
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    t0 = tcg_temp_new();
-    gen_addr_reg_index(ctx, t0);
-    tcg_gen_qemu_ld_tl(t0, t0, PPC_TLB_EPID_LOAD, DEF_MEMOP(MO_UB));
-}
-
-/* dcbi (Supervisor only) */
-static void gen_dcbi(DisasContext *ctx)
-{
-#if defined(CONFIG_USER_ONLY)
-    GEN_PRIV(ctx);
-#else
-    TCGv EA, val;
-
-    CHK_SV(ctx);
-    EA = tcg_temp_new();
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    gen_addr_reg_index(ctx, EA);
-    val = tcg_temp_new();
-    /* XXX: specification says this should be treated as a store by the MMU */
-    gen_qemu_ld8u(ctx, val, EA);
-    gen_qemu_st8(ctx, val, EA);
-#endif /* defined(CONFIG_USER_ONLY) */
-}
-
-/* dcdst */
-static void gen_dcbst(DisasContext *ctx)
-{
-    /* XXX: specification say this is treated as a load by the MMU */
-    TCGv t0;
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    t0 = tcg_temp_new();
-    gen_addr_reg_index(ctx, t0);
-    gen_qemu_ld8u(ctx, t0, t0);
-}
-
-/* dcbstep (dcbstep External PID version) */
-static void gen_dcbstep(DisasContext *ctx)
-{
-    /* XXX: specification say this is treated as a load by the MMU */
-    TCGv t0;
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    t0 = tcg_temp_new();
-    gen_addr_reg_index(ctx, t0);
-    tcg_gen_qemu_ld_tl(t0, t0, PPC_TLB_EPID_LOAD, DEF_MEMOP(MO_UB));
-}
-
-/* dcbt */
-static void gen_dcbt(DisasContext *ctx)
-{
-    /*
-     * interpreted as no-op
-     * XXX: specification say this is treated as a load by the MMU but
-     *      does not generate any exception
-     */
-}
-
-/* dcbtep */
-static void gen_dcbtep(DisasContext *ctx)
-{
-    /*
-     * interpreted as no-op
-     * XXX: specification say this is treated as a load by the MMU but
-     *      does not generate any exception
-     */
-}
-
-/* dcbtst */
-static void gen_dcbtst(DisasContext *ctx)
-{
-    /*
-     * interpreted as no-op
-     * XXX: specification say this is treated as a load by the MMU but
-     *      does not generate any exception
-     */
-}
-
-/* dcbtstep */
-static void gen_dcbtstep(DisasContext *ctx)
-{
-    /*
-     * interpreted as no-op
-     * XXX: specification say this is treated as a load by the MMU but
-     *      does not generate any exception
-     */
-}
-
-/* dcbtls */
-static void gen_dcbtls(DisasContext *ctx)
-{
-    /* Always fails locking the cache */
-    TCGv t0 = tcg_temp_new();
-    gen_load_spr(t0, SPR_Exxx_L1CSR0);
-    tcg_gen_ori_tl(t0, t0, L1CSR0_CUL);
-    gen_store_spr(SPR_Exxx_L1CSR0, t0);
-}
-
-/* dcblc */
-static void gen_dcblc(DisasContext *ctx)
-{
-    /*
-     * interpreted as no-op
-     */
-}
-
-/* dcbz */
-static void gen_dcbz(DisasContext *ctx)
-{
-    TCGv tcgv_addr = tcg_temp_new();
-
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    gen_addr_reg_index(ctx, tcgv_addr);
-
-#ifdef TARGET_PPC64
-    if (ctx->excp_model == POWERPC_EXCP_970 && !(ctx->opcode & 0x00200000)) {
-        gen_helper_dcbzl(tcg_env, tcgv_addr);
-        return;
-    }
-#endif
-
-    gen_helper_dcbz(tcg_env, tcgv_addr, tcg_constant_i32(ctx->mem_idx));
-}
-
-/* dcbzep */
-static void gen_dcbzep(DisasContext *ctx)
-{
-    TCGv tcgv_addr = tcg_temp_new();
-
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    gen_addr_reg_index(ctx, tcgv_addr);
-    gen_helper_dcbz(tcg_env, tcgv_addr, tcg_constant_i32(PPC_TLB_EPID_STORE));
-}
-
-/* dst / dstt */
-static void gen_dst(DisasContext *ctx)
-{
-    if (rA(ctx->opcode) == 0) {
-        gen_inval_exception(ctx, POWERPC_EXCP_INVAL_INVAL);
-    } else {
-        /* interpreted as no-op */
-    }
-}
-
-/* dstst /dststt */
-static void gen_dstst(DisasContext *ctx)
-{
-    if (rA(ctx->opcode) == 0) {
-        gen_inval_exception(ctx, POWERPC_EXCP_INVAL_INVAL);
-    } else {
-        /* interpreted as no-op */
-    }
-
-}
-
-/* dss / dssall */
-static void gen_dss(DisasContext *ctx)
-{
-    /* interpreted as no-op */
-}
-
-/* icbi */
-static void gen_icbi(DisasContext *ctx)
-{
-    TCGv t0;
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    t0 = tcg_temp_new();
-    gen_addr_reg_index(ctx, t0);
-    gen_helper_icbi(tcg_env, t0);
-}
-
-/* icbiep */
-static void gen_icbiep(DisasContext *ctx)
-{
-    TCGv t0;
-    gen_set_access_type(ctx, ACCESS_CACHE);
-    t0 = tcg_temp_new();
-    gen_addr_reg_index(ctx, t0);
-    gen_helper_icbiep(tcg_env, t0);
-}
-
-/* Optional: */
-/* dcba */
-static void gen_dcba(DisasContext *ctx)
-{
-    /*
-     * interpreted as no-op
-     * XXX: specification say this is treated as a store by the MMU
-     *      but does not generate any exception
-     */
-}
-
  /***                    Segment register manipulation                      
***/
  /* Supervisor only: */
@@ -5746,6 +5536,255 @@ static bool trans_LQARX(DisasContext *ctx, arg_LQARX *a)
      return true;
  }
+/*
+ * Cache Management Instructions (decodetree)
+ */
+
+static bool trans_DCBA(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, CACHE_DCBA);
+    return true;
+}
+
+static bool trans_DCBT(DisasContext *ctx, arg_X_th *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, CACHE);
+    return true;
+}
+
+static bool trans_DCBTEP(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS2(ctx, BOOKE206);
+    return true;
+}
+
+static bool trans_DCBTST(DisasContext *ctx, arg_X_th *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, CACHE);
+    return true;
+}
+
+static bool trans_DCBTSTEP(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS2(ctx, BOOKE206);
+    return true;
+}
+
+static bool trans_DCBLC(DisasContext *ctx, arg_X_th *a)
+{
+    /* Requires either PPC_BOOKE or PPC2_BOOKE206 */
+    if (!(ctx->insns_flags & PPC_BOOKE) &&
+        !(ctx->insns_flags2 & PPC2_BOOKE206)) {
+        return false;
+    }
+    return true;
+}
+
+static bool trans_DSS(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, ALTIVEC);
+    return true;
+}
+
+static bool trans_DCBTLS(DisasContext *ctx, arg_X_th *a)
+{
+    TCGv t0 = tcg_temp_new();
+
+    /* Requires either PPC_BOOKE or PPC2_BOOKE206 */
+    if (!(ctx->insns_flags & PPC_BOOKE) &&
+        !(ctx->insns_flags2 & PPC2_BOOKE206)) {
+        return false;
+    }
+
+    gen_load_spr(t0, SPR_Exxx_L1CSR0);
+    tcg_gen_ori_tl(t0, t0, L1CSR0_CUL);
+    gen_store_spr(SPR_Exxx_L1CSR0, t0);
+
+    return true;
+}
+
+static bool trans_DST(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, ALTIVEC);
+
+    if (a->ra == 0) {
+        gen_inval_exception(ctx, POWERPC_EXCP_INVAL_INVAL);
+    }
+
+    return true;
+}
+
+static bool trans_DSTST(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, ALTIVEC);
+
+    if (a->ra == 0) {
+        gen_inval_exception(ctx, POWERPC_EXCP_INVAL_INVAL);
+    }
+
+    return true;
+}
+
+static bool trans_DCBF(DisasContext *ctx, arg_X_l *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS(ctx, CACHE);
+
+    /*
+     * As per PowerISA v3.1, the L field can have values 0, 1, 3, 4, or 6.
+     * Other values are Undefined Behavior (UB).
+     */
+    switch (a->l) {
+    case 0: /* dcbf */
+    case 1: /* dcbfl */
+    case 3: /* dcbflp */
+    case 4: /* dcbfps */
+    case 6: /* dcbstps */
+        break;
+    default:
+        gen_inval_exception(ctx, POWERPC_EXCP_INVAL_INVAL);
+        return true;
+    }
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+    gen_qemu_ld8u(ctx, EA, EA);
+
+    return true;
+}
+
+static bool trans_DCBST(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS(ctx, CACHE);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+    gen_qemu_ld8u(ctx, EA, EA);
+
+    return true;
+}
+
+static bool trans_DCBFEP(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS2(ctx, BOOKE206);
+
+    REQUIRE_SV(ctx);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+
+    tcg_gen_qemu_ld_tl(EA, EA, PPC_TLB_EPID_LOAD, DEF_MEMOP(MO_UB));
+
+    return true;
+}
+
+static bool trans_DCBSTEP(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS2(ctx, BOOKE206);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+
+    tcg_gen_qemu_ld_tl(EA, EA, PPC_TLB_EPID_LOAD, DEF_MEMOP(MO_UB));
+
+    return true;
+}
+
+static bool trans_DCBI(DisasContext *ctx, arg_X_ea *a)
+{
+    REQUIRE_INSNS_FLAGS(ctx, CACHE);
+
+#if defined(CONFIG_USER_ONLY)
+    gen_priv_opc(ctx);
+    return true;
The #if defined(CONFIG_USER_ONLY) block looks redundant to me.
REQUIRE_SV is already defined for both build configurations — in
user-only builds it unconditionally calls gen_priv_opc() and returns,
and in system builds it checks ctx->pr. The manual #if split just
duplicates what REQUIRE_SV already does. The function can be simplified
to:

   static bool trans_DCBI(DisasContext *ctx, arg_X_ea *a)
   {
       REQUIRE_INSNS_FLAGS(ctx, CACHE);
       REQUIRE_SV(ctx);
gen_set_access_type(ctx, ACCESS_CACHE);
       TCGv EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
       TCGv val = tcg_temp_new();
gen_qemu_ld8u(ctx, val, EA);
       gen_qemu_st8(ctx, val, EA);
return true;
   }
Agreed ! Thanks !

Chinmay


+#else
+    TCGv EA, val;
+
+    REQUIRE_SV(ctx);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+    val = tcg_temp_new();
+
+    gen_qemu_ld8u(ctx, val, EA);
+    gen_qemu_st8(ctx, val, EA);
+
+    return true;
+#endif
+}
+
+static bool trans_ICBI(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS(ctx, CACHE_ICBI);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+    gen_helper_ICBI(tcg_env, EA);
+
+    return true;
+}
+
+static bool trans_ICBIEP(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS2(ctx, BOOKE206);
+    REQUIRE_SV(ctx);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+
+    gen_helper_ICBIEP(tcg_env, EA);
+    return true;
+}
+
+static bool trans_DCBZ(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS(ctx, CACHE_DCBZ);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+
+#if defined(TARGET_PPC64)
+    if (ctx->excp_model == POWERPC_EXCP_970 &&
+        !(ctx->opcode & 0x00200000)) {
trans_DCBZ reads ctx->opcode directly to distinguish dcbz from dcbzl on
the 970.

In a decodetree translator ctx->opcode is not reliable — the instruction
fields are decoded into arg_* before the translator is called. Bit 21
(0x00200000) is the LSB of the RT field: dcbz encodes RT=0 and the
970-specific dcbzl encodes RT=1. Since the current decode pattern

   011111----- ..... ..... 1111110110

treats all of RT as don't-care, both variants land in trans_DCBZ with
the distinguishing bit lost.

I think a better way would to split the decode entry so the table itself
separates the two:

DCBZ   011111 00000 ..... ..... 1111110110 -   @X_ea
DCBZL  011111 00001 ..... ..... 1111110110 -   @X_ea

Then trans_DCBZ needs no ctx->opcode access, and trans_DCBZL handles the
970 path cleanly with its own REQUIRE_64BIT + excp_model check.

+        gen_helper_DCBZL(tcg_env, EA);
+        return true;
+    }
+#endif
+
+    gen_helper_DCBZ(tcg_env, EA, tcg_constant_i32(ctx->mem_idx));
+    return true;
+}
+
+static bool trans_DCBZEP(DisasContext *ctx, arg_X_ea *a)
+{
+    TCGv EA;
+
+    REQUIRE_INSNS_FLAGS2(ctx, BOOKE206);
+
+    REQUIRE_SV(ctx);
+
+    gen_set_access_type(ctx, ACCESS_CACHE);
+    EA = do_ea_calc(ctx, a->ra, cpu_gpr[a->rb]);
+
+    gen_helper_DCBZ(tcg_env, EA, tcg_constant_i32(PPC_TLB_EPID_STORE));
+    return true;
+}
+
  #include "translate/fixedpoint-impl.c.inc"
#include "translate/fp-impl.c.inc"
@@ -5910,25 +5949,6 @@ GEN_HANDLER_E(mcrxrx, 0x1F, 0x00, 0x12, 0x007FF801, 
PPC_NONE, PPC2_ISA300),
  #endif
  GEN_HANDLER(mtmsr, 0x1F, 0x12, 0x04, 0x001EF801, PPC_MISC),
  GEN_HANDLER(mtspr, 0x1F, 0x13, 0x0E, 0x00000000, PPC_MISC),
-GEN_HANDLER(dcbf, 0x1F, 0x16, 0x02, 0x03C00001, PPC_CACHE),
-GEN_HANDLER_E(dcbfep, 0x1F, 0x1F, 0x03, 0x03C00001, PPC_NONE, PPC2_BOOKE206),
-GEN_HANDLER(dcbi, 0x1F, 0x16, 0x0E, 0x03E00001, PPC_CACHE),
-GEN_HANDLER(dcbst, 0x1F, 0x16, 0x01, 0x03E00001, PPC_CACHE),
-GEN_HANDLER_E(dcbstep, 0x1F, 0x1F, 0x01, 0x03E00001, PPC_NONE, PPC2_BOOKE206),
-GEN_HANDLER(dcbt, 0x1F, 0x16, 0x08, 0x00000001, PPC_CACHE),
-GEN_HANDLER_E(dcbtep, 0x1F, 0x1F, 0x09, 0x00000001, PPC_NONE, PPC2_BOOKE206),
-GEN_HANDLER(dcbtst, 0x1F, 0x16, 0x07, 0x00000001, PPC_CACHE),
-GEN_HANDLER_E(dcbtstep, 0x1F, 0x1F, 0x07, 0x00000001, PPC_NONE, PPC2_BOOKE206),
-GEN_HANDLER_E(dcbtls, 0x1F, 0x06, 0x05, 0x02000001, PPC_BOOKE, PPC2_BOOKE206),
-GEN_HANDLER_E(dcblc, 0x1F, 0x06, 0x0c, 0x02000001, PPC_BOOKE, PPC2_BOOKE206),
-GEN_HANDLER(dcbz, 0x1F, 0x16, 0x1F, 0x03C00001, PPC_CACHE_DCBZ),
-GEN_HANDLER_E(dcbzep, 0x1F, 0x1F, 0x1F, 0x03C00001, PPC_NONE, PPC2_BOOKE206),
-GEN_HANDLER(dst, 0x1F, 0x16, 0x0A, 0x01800001, PPC_ALTIVEC),
-GEN_HANDLER(dstst, 0x1F, 0x16, 0x0B, 0x01800001, PPC_ALTIVEC),
-GEN_HANDLER(dss, 0x1F, 0x16, 0x19, 0x019FF801, PPC_ALTIVEC),
[A] ^
-GEN_HANDLER(icbi, 0x1F, 0x16, 0x1E, 0x03E00001, PPC_CACHE_ICBI),
-GEN_HANDLER_E(icbiep, 0x1F, 0x1F, 0x1E, 0x03E00001, PPC_NONE, PPC2_BOOKE206),
-GEN_HANDLER(dcba, 0x1F, 0x16, 0x17, 0x03E00001, PPC_CACHE_DCBA),
  GEN_HANDLER(mfsr, 0x1F, 0x13, 0x12, 0x0010F801, PPC_SEGMENT),
  GEN_HANDLER(mfsrin, 0x1F, 0x13, 0x14, 0x001F0001, PPC_SEGMENT),
  GEN_HANDLER(mtsr, 0x1F, 0x12, 0x06, 0x0010F801, PPC_SEGMENT),
--
2.55.0


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