target-mips: make ITC Configuration Tags accessible to the CPU

Add CP0.ErrCtl register with WST, SPR and ITC bits. In 34K and interAptiv
processors these bits are used to enable CACHE instruction access to
different arrays. When WST=0, SPR=0 and ITC=1 the CACHE instruction will
access ITC tag values.

Generally we do not model caches and we have been treating the CACHE
instruction as NOP. But since CACHE can operate on ITC Tags new
MIPS_HFLAG_ITC_CACHE hflag is introduced to generate the helper only when
CACHE is in the ITC Access mode.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>

1 files changed, 52 insertions, 10 deletions

diff --git a/target-mips/translate.c b/target-mips/translate.c
index 65f2caff3e..592e4e3cd0 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -5486,8 +5486,14 @@ static void gen_mfc0(DisasContext *ctx, TCGv arg, int reg, int sel)
         }
         break;
     case 26:
-        tcg_gen_movi_tl(arg, 0); /* unimplemented */
-        rn = "ECC";
+        switch (sel) {
+        case 0:
+            gen_mfc0_load32(arg, offsetof(CPUMIPSState, CP0_ErrCtl));
+            rn = "ErrCtl";
+            break;
+        default:
+            goto cp0_unimplemented;
+        }
         break;
     case 27:
         switch (sel) {
@@ -6136,8 +6142,15 @@ static void gen_mtc0(DisasContext *ctx, TCGv arg, int reg, int sel)
         }
        break;
     case 26:
-        /* ignored */
-        rn = "ECC";
+        switch (sel) {
+        case 0:
+            gen_helper_mtc0_errctl(cpu_env, arg);
+            ctx->bstate = BS_STOP;
+            rn = "ErrCtl";
+            break;
+        default:
+            goto cp0_unimplemented;
+        }
         break;
     case 27:
         switch (sel) {
@@ -6762,8 +6775,14 @@ static void gen_dmfc0(DisasContext *ctx, TCGv arg, int reg, int sel)
         }
         break;
     case 26:
-        tcg_gen_movi_tl(arg, 0); /* unimplemented */
-        rn = "ECC";
+        switch (sel) {
+        case 0:
+            gen_mfc0_load32(arg, offsetof(CPUMIPSState, CP0_ErrCtl));
+            rn = "ErrCtl";
+            break;
+        default:
+            goto cp0_unimplemented;
+        }
         break;
     case 27:
         switch (sel) {
@@ -7404,8 +7423,15 @@ static void gen_dmtc0(DisasContext *ctx, TCGv arg, int reg, int sel)
         }
         break;
     case 26:
-        /* ignored */
-        rn = "ECC";
+        switch (sel) {
+        case 0:
+            gen_helper_mtc0_errctl(cpu_env, arg);
+            ctx->bstate = BS_STOP;
+            rn = "ErrCtl";
+            break;
+        default:
+            goto cp0_unimplemented;
+        }
         break;
     case 27:
         switch (sel) {
@@ -11190,6 +11216,15 @@ static void gen_addiupc (DisasContext *ctx, int rx, int imm,
     tcg_temp_free(t0);
 }
 
+static void gen_cache_operation(DisasContext *ctx, uint32_t op, int base,
+                                int16_t offset)
+{
+    TCGv_i32 t0 = tcg_const_i32(op);
+    TCGv t1 = tcg_temp_new();
+    gen_base_offset_addr(ctx, t1, base, offset);
+    gen_helper_cache(cpu_env, t1, t0);
+}
+
 #if defined(TARGET_MIPS64)
 static void decode_i64_mips16 (DisasContext *ctx,
                                int ry, int funct, int16_t offset,
@@ -13741,7 +13776,9 @@ static void decode_micromips32_opc(CPUMIPSState *env, DisasContext *ctx)
         switch (minor) {
         case CACHE:
             check_cp0_enabled(ctx);
-            /* Treat as no-op. */
+            if (ctx->hflags & MIPS_HFLAG_ITC_CACHE) {
+                gen_cache_operation(ctx, rt, rs, imm);
+            }
             break;
         case LWC2:
         case SWC2:
@@ -17195,7 +17232,9 @@ static void decode_opc_special3_r6(CPUMIPSState *env, DisasContext *ctx)
         break;
     case R6_OPC_CACHE:
         check_cp0_enabled(ctx);
-        /* Treat as NOP. */
+        if (ctx->hflags & MIPS_HFLAG_ITC_CACHE) {
+            gen_cache_operation(ctx, rt, rs, imm);
+        }
         break;
     case R6_OPC_SC:
         gen_st_cond(ctx, op1, rt, rs, imm);
@@ -19304,6 +19343,9 @@ static void decode_opc(CPUMIPSState *env, DisasContext *ctx)
         check_insn_opc_removed(ctx, ISA_MIPS32R6);
         check_cp0_enabled(ctx);
         check_insn(ctx, ISA_MIPS3 | ISA_MIPS32);
+        if (ctx->hflags & MIPS_HFLAG_ITC_CACHE) {
+            gen_cache_operation(ctx, rt, rs, imm);
+        }
         /* Treat as NOP. */
         break;
     case OPC_PREF: