target-mips: add mips16 instruction decoding

There's no good way to add this incrementally, so we do it all at once.
The only changes to shared code are in handle_delay_slot.  We need to
flip ISAMode when doing a jump-and-exchange.  We also need to set
ISAMode the low bit of the target address for jump-to-register.

Also, since we're now adding bits that can be in MIPS_HFLAG_BMASK_EXT,
make sure we use MIPS_HFLAG_BMASK_BASE in the places where we just want
basic information about a branch.

Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 1063 insertions, 9 deletions

diff --git a/target-mips/translate.c b/target-mips/translate.c
index cc18113..a3f5f72 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -83,6 +83,7 @@ enum {
     OPC_LH       = (0x21 << 26),
     OPC_LWL      = (0x22 << 26),
     OPC_LW       = (0x23 << 26),
+    OPC_LWPC     = OPC_LW | 0x5,
     OPC_LBU      = (0x24 << 26),
     OPC_LHU      = (0x25 << 26),
     OPC_LWR      = (0x26 << 26),
@@ -97,6 +98,7 @@ enum {
     OPC_LL       = (0x30 << 26),
     OPC_LLD      = (0x34 << 26),
     OPC_LD       = (0x37 << 26),
+    OPC_LDPC     = OPC_LD | 0x5,
     OPC_SC       = (0x38 << 26),
     OPC_SCD      = (0x3C << 26),
     OPC_SD       = (0x3F << 26),
@@ -173,6 +175,7 @@ enum {
     /* Jumps */
     OPC_JR       = 0x08 | OPC_SPECIAL, /* Also JR.HB */
     OPC_JALR     = 0x09 | OPC_SPECIAL, /* Also JALR.HB */
+    OPC_JALRC    = OPC_JALR | (0x5 << 6),
     /* Traps */
     OPC_TGE      = 0x30 | OPC_SPECIAL,
     OPC_TGEU     = 0x31 | OPC_SPECIAL,
@@ -763,7 +766,7 @@ static inline void save_cpu_state (DisasContext *ctx, int do_save_pc)
     if (ctx->hflags != ctx->saved_hflags) {
         tcg_gen_movi_i32(hflags, ctx->hflags);
         ctx->saved_hflags = ctx->hflags;
-        switch (ctx->hflags & MIPS_HFLAG_BMASK) {
+        switch (ctx->hflags & MIPS_HFLAG_BMASK_BASE) {
         case MIPS_HFLAG_BR:
             break;
         case MIPS_HFLAG_BC:
@@ -778,7 +781,7 @@ static inline void save_cpu_state (DisasContext *ctx, int do_save_pc)
 static inline void restore_cpu_state (CPUState *env, DisasContext *ctx)
 {
     ctx->saved_hflags = ctx->hflags;
-    switch (ctx->hflags & MIPS_HFLAG_BMASK) {
+    switch (ctx->hflags & MIPS_HFLAG_BMASK_BASE) {
     case MIPS_HFLAG_BR:
         break;
     case MIPS_HFLAG_BC:
@@ -994,6 +997,20 @@ static void gen_base_offset_addr (DisasContext *ctx, TCGv addr,
     }
 }
 
+static target_ulong pc_relative_pc (DisasContext *ctx)
+{
+    target_ulong pc = ctx->pc;
+
+    if (ctx->hflags & MIPS_HFLAG_BMASK) {
+        int branch_bytes = ctx->hflags & MIPS_HFLAG_BDS16 ? 2 : 4;
+
+        pc -= branch_bytes;
+    }
+
+    pc &= ~(target_ulong)3;
+    return pc;
+}
+
 /* Load and store */
 static void gen_ldst (DisasContext *ctx, uint32_t opc, int rt,
                       int base, int16_t offset)
@@ -1057,7 +1074,21 @@ static void gen_ldst (DisasContext *ctx, uint32_t opc, int rt,
         gen_helper_2i(sdr, t1, t0, ctx->mem_idx);
         opn = "sdr";
         break;
+    case OPC_LDPC:
+        save_cpu_state(ctx, 1);
+        tcg_gen_movi_tl(t1, pc_relative_pc(ctx));
+        gen_op_addr_add(ctx, t0, t0, t1);
+        op_ldst_ld(t0, t0, ctx);
+        gen_store_gpr(t0, rt);
+        break;
 #endif
+    case OPC_LWPC:
+        save_cpu_state(ctx, 1);
+        tcg_gen_movi_tl(t1, pc_relative_pc(ctx));
+        gen_op_addr_add(ctx, t0, t0, t1);
+        op_ldst_lw(t0, t0, ctx);
+        gen_store_gpr(t0, rt);
+        break;
     case OPC_LW:
         save_cpu_state(ctx, 0);
         op_ldst_lw(t0, t0, ctx);
@@ -2434,11 +2465,13 @@ static void gen_compute_branch (DisasContext *ctx, uint32_t opc,
         break;
     case OPC_J:
     case OPC_JAL:
+    case OPC_JALX:
         /* Jump to immediate */
         btgt = ((ctx->pc + insn_bytes) & (int32_t)0xF0000000) | (uint32_t)offset;
         break;
     case OPC_JR:
     case OPC_JALR:
+    case OPC_JALRC:
         /* Jump to register */
         if (offset != 0 && offset != 16) {
             /* Hint = 0 is JR/JALR, hint 16 is JR.HB/JALR.HB, the
@@ -2501,18 +2534,29 @@ static void gen_compute_branch (DisasContext *ctx, uint32_t opc,
             ctx->hflags |= MIPS_HFLAG_B;
             MIPS_DEBUG("j " TARGET_FMT_lx, btgt);
             break;
+        case OPC_JALX:
+            ctx->hflags |= MIPS_HFLAG_BX;
+            /* Fallthrough */
         case OPC_JAL:
             blink = 31;
             ctx->hflags |= MIPS_HFLAG_B;
+            ctx->hflags |= (ctx->hflags & MIPS_HFLAG_M16
+                            ? MIPS_HFLAG_BDS16
+                            : MIPS_HFLAG_BDS32);
             MIPS_DEBUG("jal " TARGET_FMT_lx, btgt);
             break;
         case OPC_JR:
             ctx->hflags |= MIPS_HFLAG_BR;
+            if (ctx->hflags & MIPS_HFLAG_M16)
+                ctx->hflags |= MIPS_HFLAG_BDS16;
             MIPS_DEBUG("jr %s", regnames[rs]);
             break;
         case OPC_JALR:
+        case OPC_JALRC:
             blink = rt;
             ctx->hflags |= MIPS_HFLAG_BR;
+            if (ctx->hflags & MIPS_HFLAG_M16)
+                ctx->hflags |= MIPS_HFLAG_BDS16;
             MIPS_DEBUG("jalr %s, %s", regnames[rt], regnames[rs]);
             break;
         default:
@@ -2609,10 +2653,18 @@ static void gen_compute_branch (DisasContext *ctx, uint32_t opc,
 
     ctx->btarget = btgt;
     if (blink > 0) {
-        tcg_gen_movi_tl(cpu_gpr[blink], ctx->pc + 8);
+        int post_delay = insn_bytes;
+        int lowbit = !!(ctx->hflags & MIPS_HFLAG_M16);
+
+        if (opc != OPC_JALRC)
+            post_delay += ((ctx->hflags & MIPS_HFLAG_BDS16) ? 2 : 4);
+
+        tcg_gen_movi_tl(cpu_gpr[blink], ctx->pc + post_delay + lowbit);
     }
 
  out:
+    if (insn_bytes == 2)
+        ctx->hflags |= MIPS_HFLAG_B16;
     tcg_temp_free(t0);
     tcg_temp_free(t1);
 }
@@ -7536,16 +7588,19 @@ static void handle_delay_slot (CPUState *env, DisasContext *ctx,
                                int insn_bytes)
 {
     if (ctx->hflags & MIPS_HFLAG_BMASK) {
-        int hflags = ctx->hflags & MIPS_HFLAG_BMASK;
+        int proc_hflags = ctx->hflags & MIPS_HFLAG_BMASK;
         /* Branches completion */
         ctx->hflags &= ~MIPS_HFLAG_BMASK;
         ctx->bstate = BS_BRANCH;
         save_cpu_state(ctx, 0);
         /* FIXME: Need to clear can_do_io.  */
-        switch (hflags) {
+        switch (proc_hflags & MIPS_HFLAG_BMASK_BASE) {
         case MIPS_HFLAG_B:
             /* unconditional branch */
             MIPS_DEBUG("unconditional branch");
+            if (proc_hflags & MIPS_HFLAG_BX) {
+                tcg_gen_xori_i32(hflags, hflags, MIPS_HFLAG_M16);
+            }
             gen_goto_tb(ctx, 0, ctx->btarget);
             break;
         case MIPS_HFLAG_BL:
@@ -7568,7 +7623,22 @@ static void handle_delay_slot (CPUState *env, DisasContext *ctx,
         case MIPS_HFLAG_BR:
             /* unconditional branch to register */
             MIPS_DEBUG("branch to register");
-            tcg_gen_mov_tl(cpu_PC, btarget);
+            if (env->insn_flags & ASE_MIPS16) {
+                TCGv t0 = tcg_temp_new();
+                TCGv_i32 t1 = tcg_temp_new_i32();
+
+                tcg_gen_andi_tl(t0, btarget, 0x1);
+                tcg_gen_trunc_tl_i32(t1, t0);
+                tcg_temp_free(t0);
+                tcg_gen_andi_i32(hflags, hflags, ~(uint32_t)MIPS_HFLAG_M16);
+                tcg_gen_shli_i32(t1, t1, MIPS_HFLAG_M16_SHIFT);
+                tcg_gen_or_i32(hflags, hflags, t1);
+                tcg_temp_free_i32(t1);
+
+                tcg_gen_andi_tl(cpu_PC, btarget, ~(target_ulong)0x1);
+            } else {
+                tcg_gen_mov_tl(cpu_PC, btarget);
+            }
             if (ctx->singlestep_enabled) {
                 save_cpu_state(ctx, 0);
                 gen_helper_0i(raise_exception, EXCP_DEBUG);
@@ -7681,7 +7751,7 @@ enum {
   I64_SDRASP = 0x2,
   I64_DADJSP = 0x3,
   I64_LDPC = 0x4,
-  I64_DADDIU = 0x5,
+  I64_DADDIU5 = 0x5,
   I64_DADDIUPC = 0x6,
   I64_DADDIUSP = 0x7
 };
@@ -7696,6 +7766,984 @@ enum {
   RR_RY_CNVT_SEW = 0x6,
 };
 
+static int xlat (int r)
+{
+  static int map[] = { 16, 17, 2, 3, 4, 5, 6, 7 };
+
+  return map[r];
+}
+
+static void gen_mips16_save (DisasContext *ctx,
+                             int xsregs, int aregs,
+                             int do_ra, int do_s0, int do_s1,
+                             int framesize)
+{
+    TCGv t0 = tcg_temp_new();
+    TCGv t1 = tcg_temp_new();
+    int args, astatic;
+
+    switch (aregs) {
+    case 0:
+    case 1:
+    case 2:
+    case 3:
+    case 11:
+        args = 0;
+        break;
+    case 4:
+    case 5:
+    case 6:
+    case 7:
+        args = 1;
+        break;
+    case 8:
+    case 9:
+    case 10:
+        args = 2;
+        break;
+    case 12:
+    case 13:
+        args = 3;
+        break;
+    case 14:
+        args = 4;
+        break;
+    default:
+        generate_exception(ctx, EXCP_RI);
+        return;
+    }
+
+    switch (args) {
+    case 4:
+        gen_base_offset_addr(ctx, t0, 29, 12);
+        gen_load_gpr(t1, 7);
+        op_ldst_sw(t1, t0, ctx);
+        /* Fall through */
+    case 3:
+        gen_base_offset_addr(ctx, t0, 29, 8);
+        gen_load_gpr(t1, 6);
+        op_ldst_sw(t1, t0, ctx);
+        /* Fall through */
+    case 2:
+        gen_base_offset_addr(ctx, t0, 29, 4);
+        gen_load_gpr(t1, 5);
+        op_ldst_sw(t1, t0, ctx);
+        /* Fall through */
+    case 1:
+        gen_base_offset_addr(ctx, t0, 29, 0);
+        gen_load_gpr(t1, 4);
+        op_ldst_sw(t1, t0, ctx);
+    }
+
+    gen_load_gpr(t0, 29);
+
+#define DECR_AND_STORE(reg) do {                \
+        tcg_gen_subi_tl(t0, t0, 4);             \
+        gen_load_gpr(t1, reg);                  \
+        op_ldst_sw(t1, t0, ctx);                \
+    } while (0)
+
+    if (do_ra) {
+        DECR_AND_STORE(31);
+    }
+
+    switch (xsregs) {
+    case 7:
+        DECR_AND_STORE(30);
+        /* Fall through */
+    case 6:
+        DECR_AND_STORE(23);
+        /* Fall through */
+    case 5:
+        DECR_AND_STORE(22);
+        /* Fall through */
+    case 4:
+        DECR_AND_STORE(21);
+        /* Fall through */
+    case 3:
+        DECR_AND_STORE(20);
+        /* Fall through */
+    case 2:
+        DECR_AND_STORE(19);
+        /* Fall through */
+    case 1:
+        DECR_AND_STORE(18);
+    }
+
+    if (do_s1) {
+        DECR_AND_STORE(17);
+    }
+    if (do_s0) {
+        DECR_AND_STORE(16);
+    }
+
+    switch (aregs) {
+    case 0:
+    case 4:
+    case 8:
+    case 12:
+    case 14:
+        astatic = 0;
+        break;
+    case 1:
+    case 5:
+    case 9:
+    case 13:
+        astatic = 1;
+        break;
+    case 2:
+    case 6:
+    case 10:
+        astatic = 2;
+        break;
+    case 3:
+    case 7:
+        astatic = 3;
+        break;
+    case 11:
+        astatic = 4;
+        break;
+    default:
+        generate_exception(ctx, EXCP_RI);
+        return;
+    }
+
+    if (astatic > 0) {
+        DECR_AND_STORE(7);
+        if (astatic > 1) {
+            DECR_AND_STORE(6);
+            if (astatic > 2) {
+                DECR_AND_STORE(5);
+                if (astatic > 3) {
+                    DECR_AND_STORE(4);
+                }
+            }
+        }
+    }
+#undef DECR_AND_STORE
+
+    tcg_gen_subi_tl(cpu_gpr[29], cpu_gpr[29], framesize);
+    tcg_temp_free(t0);
+    tcg_temp_free(t1);
+}
+
+static void gen_mips16_restore (DisasContext *ctx,
+                                int xsregs, int aregs,
+                                int do_ra, int do_s0, int do_s1,
+                                int framesize)
+{
+    int astatic;
+    TCGv t0 = tcg_temp_new();
+    TCGv t1 = tcg_temp_new();
+
+    tcg_gen_addi_tl(t0, cpu_gpr[29], framesize);
+
+#define DECR_AND_LOAD(reg) do {                 \
+        tcg_gen_subi_tl(t0, t0, 4);             \
+        op_ldst_lw(t1, t0, ctx);                \
+        gen_store_gpr(t1, reg);                 \
+    } while (0)
+
+    if (do_ra) {
+        DECR_AND_LOAD(31);
+    }
+
+    switch (xsregs) {
+    case 7:
+        DECR_AND_LOAD(30);
+        /* Fall through */
+    case 6:
+        DECR_AND_LOAD(23);
+        /* Fall through */
+    case 5:
+        DECR_AND_LOAD(22);
+        /* Fall through */
+    case 4:
+        DECR_AND_LOAD(21);
+        /* Fall through */
+    case 3:
+        DECR_AND_LOAD(20);
+        /* Fall through */
+    case 2:
+        DECR_AND_LOAD(19);
+        /* Fall through */
+    case 1:
+        DECR_AND_LOAD(18);
+    }
+
+    if (do_s1) {
+        DECR_AND_LOAD(17);
+    }
+    if (do_s0) {
+        DECR_AND_LOAD(16);
+    }
+
+    switch (aregs) {
+    case 0:
+    case 4:
+    case 8:
+    case 12:
+    case 14:
+        astatic = 0;
+        break;
+    case 1:
+    case 5:
+    case 9:
+    case 13:
+        astatic = 1;
+        break;
+    case 2:
+    case 6:
+    case 10:
+        astatic = 2;
+        break;
+    case 3:
+    case 7:
+        astatic = 3;
+        break;
+    case 11:
+        astatic = 4;
+        break;
+    default:
+        generate_exception(ctx, EXCP_RI);
+        return;
+    }
+
+    if (astatic > 0) {
+        DECR_AND_LOAD(7);
+        if (astatic > 1) {
+            DECR_AND_LOAD(6);
+            if (astatic > 2) {
+                DECR_AND_LOAD(5);
+                if (astatic > 3) {
+                    DECR_AND_LOAD(4);
+                }
+            }
+        }
+    }
+#undef DECR_AND_LOAD
+
+    tcg_gen_addi_tl(cpu_gpr[29], cpu_gpr[29], framesize);
+    tcg_temp_free(t0);
+    tcg_temp_free(t1);
+}
+
+static void gen_addiupc (DisasContext *ctx, int rx, int imm,
+                         int is_64_bit, int extended)
+{
+    TCGv t0;
+
+    if (extended && (ctx->hflags & MIPS_HFLAG_BMASK)) {
+        generate_exception(ctx, EXCP_RI);
+        return;
+    }
+
+    t0 = tcg_temp_new();
+
+    tcg_gen_movi_tl(t0, pc_relative_pc(ctx));
+    tcg_gen_addi_tl(cpu_gpr[rx], t0, imm);
+    if (!is_64_bit) {
+        tcg_gen_ext32s_tl(cpu_gpr[rx], cpu_gpr[rx]);
+    }
+
+    tcg_temp_free(t0);
+}
+
+#if defined(TARGET_MIPS64)
+static void decode_i64_mips16 (CPUState *env, DisasContext *ctx,
+                               int ry, int funct, int16_t offset,
+                               int extended)
+{
+    switch (funct) {
+    case I64_LDSP:
+        check_mips_64(ctx);
+        offset = extended ? offset : offset << 3;
+        gen_ldst(ctx, OPC_LD, ry, 29, offset);
+        break;
+    case I64_SDSP:
+        check_mips_64(ctx);
+        offset = extended ? offset : offset << 3;
+        gen_ldst(ctx, OPC_SD, ry, 29, offset);
+        break;
+    case I64_SDRASP:
+        check_mips_64(ctx);
+        offset = extended ? offset : (ctx->opcode & 0xff) << 3;
+        gen_ldst(ctx, OPC_SD, 31, 29, offset);
+        break;
+    case I64_DADJSP:
+        check_mips_64(ctx);
+        offset = extended ? offset : ((int8_t)ctx->opcode) << 3;
+        gen_arith_imm(env, ctx, OPC_DADDIU, 29, 29, offset);
+        break;
+    case I64_LDPC:
+        if (extended && (ctx->hflags & MIPS_HFLAG_BMASK)) {
+            generate_exception(ctx, EXCP_RI);
+        } else {
+            offset = extended ? offset : offset << 3;
+            gen_ldst(ctx, OPC_LDPC, ry, 0, offset);
+        }
+        break;
+    case I64_DADDIU5:
+        check_mips_64(ctx);
+        offset = extended ? offset : ((int8_t)(offset << 3)) >> 3;
+        gen_arith_imm(env, ctx, OPC_DADDIU, ry, ry, offset);
+        break;
+    case I64_DADDIUPC:
+        check_mips_64(ctx);
+        offset = extended ? offset : offset << 2;
+        gen_addiupc(ctx, ry, offset, 1, extended);
+        break;
+    case I64_DADDIUSP:
+        check_mips_64(ctx);
+        offset = extended ? offset : offset << 2;
+        gen_arith_imm(env, ctx, OPC_DADDIU, ry, 29, offset);
+        break;
+    }
+}
+#endif
+
+static int decode_extended_mips16_opc (CPUState *env, DisasContext *ctx,
+                                       int *is_branch)
+{
+    int extend = lduw_code(ctx->pc + 2);
+    int op, rx, ry, funct, sa;
+    int16_t imm, offset;
+
+    ctx->opcode = (ctx->opcode << 16) | extend;
+    op = (ctx->opcode >> 11) & 0x1f;
+    sa = (ctx->opcode >> 22) & 0x1f;
+    funct = (ctx->opcode >> 8) & 0x7;
+    rx = xlat((ctx->opcode >> 8) & 0x7);
+    ry = xlat((ctx->opcode >> 5) & 0x7);
+    offset = imm = (int16_t) (((ctx->opcode >> 16) & 0x1f) << 11
+                              | ((ctx->opcode >> 21) & 0x3f) << 5
+                              | (ctx->opcode & 0x1f));
+
+    /* The extended opcodes cleverly reuse the opcodes from their 16-bit
+       counterparts.  */
+    switch (op) {
+    case M16_OPC_ADDIUSP:
+        gen_arith_imm(env, ctx, OPC_ADDIU, rx, 29, imm);
+        break;
+    case M16_OPC_ADDIUPC:
+        gen_addiupc(ctx, rx, imm, 0, 1);
+        break;
+    case M16_OPC_B:
+        gen_compute_branch(ctx, OPC_BEQ, 4, 0, 0, offset << 1);
+        /* No delay slot, so just process as a normal instruction */
+        break;
+    case M16_OPC_BEQZ:
+        gen_compute_branch(ctx, OPC_BEQ, 4, rx, 0, offset << 1);
+        /* No delay slot, so just process as a normal instruction */
+        break;
+    case M16_OPC_BNEQZ:
+        gen_compute_branch(ctx, OPC_BNE, 4, rx, 0, offset << 1);
+        /* No delay slot, so just process as a normal instruction */
+        break;
+    case M16_OPC_SHIFT:
+        switch (ctx->opcode & 0x3) {
+        case 0x0:
+            gen_shift_imm(env, ctx, OPC_SLL, rx, ry, sa);
+            break;
+        case 0x1:
+#if defined(TARGET_MIPS64)
+            check_mips_64(ctx);
+            gen_shift_imm(env, ctx, OPC_DSLL, rx, ry, sa);
+#else
+            generate_exception(ctx, EXCP_RI);
+#endif
+            break;
+        case 0x2:
+            gen_shift_imm(env, ctx, OPC_SRL, rx, ry, sa);
+            break;
+        case 0x3:
+            gen_shift_imm(env, ctx, OPC_SRA, rx, ry, sa);
+            break;
+        }
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_LD:
+            check_mips_64(ctx);
+        gen_ldst(ctx, OPC_LD, ry, rx, offset);
+        break;
+#endif
+    case M16_OPC_RRIA:
+        imm = ctx->opcode & 0xf;
+        imm = imm | ((ctx->opcode >> 20) & 0x7f) << 4;
+        imm = imm | ((ctx->opcode >> 16) & 0xf) << 11;
+        imm = (int16_t) (imm << 1) >> 1;
+        if ((ctx->opcode >> 4) & 0x1) {
+#if defined(TARGET_MIPS64)
+            check_mips_64(ctx);
+            gen_arith_imm(env, ctx, OPC_DADDIU, ry, rx, imm);
+#else
+            generate_exception(ctx, EXCP_RI);
+#endif
+        } else {
+            gen_arith_imm(env, ctx, OPC_ADDIU, ry, rx, imm);
+        }
+        break;
+    case M16_OPC_ADDIU8:
+        gen_arith_imm(env, ctx, OPC_ADDIU, rx, rx, imm);
+        break;
+    case M16_OPC_SLTI:
+        gen_slt_imm(env, OPC_SLTI, 24, rx, imm);
+        break;
+    case M16_OPC_SLTIU:
+        gen_slt_imm(env, OPC_SLTIU, 24, rx, imm);
+        break;
+    case M16_OPC_I8:
+        switch (funct) {
+        case I8_BTEQZ:
+            gen_compute_branch(ctx, OPC_BEQ, 4, 24, 0, offset << 1);
+            break;
+        case I8_BTNEZ:
+            gen_compute_branch(ctx, OPC_BNE, 4, 24, 0, offset << 1);
+            break;
+        case I8_SWRASP:
+            gen_ldst(ctx, OPC_SW, 31, 29, imm);
+            break;
+        case I8_ADJSP:
+            gen_arith_imm(env, ctx, OPC_ADDIU, 29, 29, imm);
+            break;
+        case I8_SVRS:
+            {
+                int xsregs = (ctx->opcode >> 24) & 0x7;
+                int aregs = (ctx->opcode >> 16) & 0xf;
+                int do_ra = (ctx->opcode >> 6) & 0x1;
+                int do_s0 = (ctx->opcode >> 5) & 0x1;
+                int do_s1 = (ctx->opcode >> 4) & 0x1;
+                int framesize = (((ctx->opcode >> 20) & 0xf) << 4
+                                 | (ctx->opcode & 0xf)) << 3;
+
+                if (ctx->opcode & (1 << 7)) {
+                    gen_mips16_save(ctx, xsregs, aregs,
+                                    do_ra, do_s0, do_s1,
+                                    framesize);
+                } else {
+                    gen_mips16_restore(ctx, xsregs, aregs,
+                                       do_ra, do_s0, do_s1,
+                                       framesize);
+                }
+            }
+            break;
+        default:
+            generate_exception(ctx, EXCP_RI);
+            break;
+        }
+        break;
+    case M16_OPC_LI:
+        tcg_gen_movi_tl(cpu_gpr[rx], (uint16_t) imm);
+        break;
+    case M16_OPC_CMPI:
+        tcg_gen_xori_tl(cpu_gpr[24], cpu_gpr[rx], (uint16_t) imm);
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_SD:
+        gen_ldst(ctx, OPC_SD, ry, rx, offset);
+        break;
+#endif
+    case M16_OPC_LB:
+        gen_ldst(ctx, OPC_LB, ry, rx, offset);
+        break;
+    case M16_OPC_LH:
+        gen_ldst(ctx, OPC_LH, ry, rx, offset);
+        break;
+    case M16_OPC_LWSP:
+        gen_ldst(ctx, OPC_LW, rx, 29, offset);
+        break;
+    case M16_OPC_LW:
+        gen_ldst(ctx, OPC_LW, ry, rx, offset);
+        break;
+    case M16_OPC_LBU:
+        gen_ldst(ctx, OPC_LBU, ry, rx, offset);
+        break;
+    case M16_OPC_LHU:
+        gen_ldst(ctx, OPC_LHU, ry, rx, offset);
+        break;
+    case M16_OPC_LWPC:
+        gen_ldst(ctx, OPC_LWPC, rx, 0, offset);
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_LWU:
+        gen_ldst(ctx, OPC_LWU, ry, rx, offset);
+        break;
+#endif
+    case M16_OPC_SB:
+        gen_ldst(ctx, OPC_SB, ry, rx, offset);
+        break;
+    case M16_OPC_SH:
+        gen_ldst(ctx, OPC_SH, ry, rx, offset);
+        break;
+    case M16_OPC_SWSP:
+        gen_ldst(ctx, OPC_SW, rx, 29, offset);
+        break;
+    case M16_OPC_SW:
+        gen_ldst(ctx, OPC_SW, ry, rx, offset);
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_I64:
+        decode_i64_mips16(env, ctx, ry, funct, offset, 1);
+        break;
+#endif
+    default:
+        generate_exception(ctx, EXCP_RI);
+        break;
+    }
+
+    return 4;
+}
+
+static int decode_mips16_opc (CPUState *env, DisasContext *ctx,
+                              int *is_branch)
+{
+    int rx, ry;
+    int sa;
+    int op, cnvt_op, op1, offset;
+    int funct;
+    int n_bytes;
+
+    op = (ctx->opcode >> 11) & 0x1f;
+    sa = (ctx->opcode >> 2) & 0x7;
+    sa = sa == 0 ? 8 : sa;
+    rx = xlat((ctx->opcode >> 8) & 0x7);
+    cnvt_op = (ctx->opcode >> 5) & 0x7;
+    ry = xlat((ctx->opcode >> 5) & 0x7);
+    op1 = offset = ctx->opcode & 0x1f;
+
+    n_bytes = 2;
+
+    switch (op) {
+    case M16_OPC_ADDIUSP:
+        {
+            int16_t imm = ((uint8_t) ctx->opcode) << 2;
+
+            gen_arith_imm(env, ctx, OPC_ADDIU, rx, 29, imm);
+        }
+        break;
+    case M16_OPC_ADDIUPC:
+        gen_addiupc(ctx, rx, ((uint8_t) ctx->opcode) << 2, 0, 0);
+        break;
+    case M16_OPC_B:
+        offset = (ctx->opcode & 0x7ff) << 1;
+        offset = (int16_t)(offset << 4) >> 4;
+        gen_compute_branch(ctx, OPC_BEQ, 2, 0, 0, offset);
+        /* No delay slot, so just process as a normal instruction */
+        break;
+    case M16_OPC_JAL:
+        offset = lduw_code(ctx->pc + 2);
+        offset = (((ctx->opcode & 0x1f) << 21)
+                  | ((ctx->opcode >> 5) & 0x1f) << 16
+                  | offset) << 2;
+        op = ((ctx->opcode >> 10) & 0x1) ? OPC_JALX : OPC_JAL;
+        gen_compute_branch(ctx, op, 4, rx, ry, offset);
+        n_bytes = 4;
+        *is_branch = 1;
+        break;
+    case M16_OPC_BEQZ:
+        gen_compute_branch(ctx, OPC_BEQ, 2, rx, 0, ((int8_t)ctx->opcode) << 1);
+        /* No delay slot, so just process as a normal instruction */
+        break;
+    case M16_OPC_BNEQZ:
+        gen_compute_branch(ctx, OPC_BNE, 2, rx, 0, ((int8_t)ctx->opcode) << 1);
+        /* No delay slot, so just process as a normal instruction */
+        break;
+    case M16_OPC_SHIFT:
+        switch (ctx->opcode & 0x3) {
+        case 0x0:
+            gen_shift_imm(env, ctx, OPC_SLL, rx, ry, sa);
+            break;
+        case 0x1:
+#if defined(TARGET_MIPS64)
+            check_mips_64(ctx);
+            gen_shift_imm(env, ctx, OPC_DSLL, rx, ry, sa);
+#else
+            generate_exception(ctx, EXCP_RI);
+#endif
+            break;
+        case 0x2:
+            gen_shift_imm(env, ctx, OPC_SRL, rx, ry, sa);
+            break;
+        case 0x3:
+            gen_shift_imm(env, ctx, OPC_SRA, rx, ry, sa);
+            break;
+        }
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_LD:
+        check_mips_64(ctx);
+        gen_ldst(ctx, OPC_LD, ry, rx, offset << 3);
+        break;
+#endif
+    case M16_OPC_RRIA:
+        {
+            int16_t imm = (int8_t)((ctx->opcode & 0xf) << 4) >> 4;
+
+            if ((ctx->opcode >> 4) & 1) {
+#if defined(TARGET_MIPS64)
+                check_mips_64(ctx);
+                gen_arith_imm(env, ctx, OPC_DADDIU, ry, rx, imm);
+#else
+                generate_exception(ctx, EXCP_RI);
+#endif
+            } else {
+                gen_arith_imm(env, ctx, OPC_ADDIU, ry, rx, imm);
+            }
+        }
+        break;
+    case M16_OPC_ADDIU8:
+        {
+            int16_t imm = (int8_t) ctx->opcode;
+
+            gen_arith_imm(env, ctx, OPC_ADDIU, rx, rx, imm);
+        }
+        break;
+    case M16_OPC_SLTI:
+        {
+            int16_t imm = (uint8_t) ctx->opcode;
+
+            gen_slt_imm(env, OPC_SLTI, 24, rx, imm);
+        }
+        break;
+    case M16_OPC_SLTIU:
+        {
+            int16_t imm = (uint8_t) ctx->opcode;
+
+            gen_slt_imm(env, OPC_SLTIU, 24, rx, imm);
+        }
+        break;
+    case M16_OPC_I8:
+        {
+            int reg32;
+
+            funct = (ctx->opcode >> 8) & 0x7;
+            switch (funct) {
+            case I8_BTEQZ:
+                gen_compute_branch(ctx, OPC_BEQ, 2, 24, 0,
+                                   ((int8_t)ctx->opcode) << 1);
+                break;
+            case I8_BTNEZ:
+                gen_compute_branch(ctx, OPC_BNE, 2, 24, 0,
+                                   ((int8_t)ctx->opcode) << 1);
+                break;
+            case I8_SWRASP:
+                gen_ldst(ctx, OPC_SW, 31, 29, (ctx->opcode & 0xff) << 2);
+                break;
+            case I8_ADJSP:
+                gen_arith_imm(env, ctx, OPC_ADDIU, 29, 29,
+                              ((int8_t)ctx->opcode) << 3);
+                break;
+            case I8_SVRS:
+                {
+                    int do_ra = ctx->opcode & (1 << 6);
+                    int do_s0 = ctx->opcode & (1 << 5);
+                    int do_s1 = ctx->opcode & (1 << 4);
+                    int framesize = ctx->opcode & 0xf;
+
+                    if (framesize == 0) {
+                        framesize = 128;
+                    } else {
+                        framesize = framesize << 3;
+                    }
+
+                    if (ctx->opcode & (1 << 7)) {
+                        gen_mips16_save(ctx, 0, 0,
+                                        do_ra, do_s0, do_s1, framesize);
+                    } else {
+                        gen_mips16_restore(ctx, 0, 0,
+                                           do_ra, do_s0, do_s1, framesize);
+                    }
+                }
+                break;
+            case I8_MOV32R:
+                {
+                    int rz = xlat(ctx->opcode & 0x7);
+
+                    reg32 = (((ctx->opcode >> 3) & 0x3) << 3) |
+                        ((ctx->opcode >> 5) & 0x7);
+                    gen_arith(env, ctx, OPC_ADDU, reg32, rz, 0);
+                }
+                break;
+            case I8_MOVR32:
+                reg32 = ctx->opcode & 0x1f;
+                gen_arith(env, ctx, OPC_ADDU, ry, reg32, 0);
+                break;
+            default:
+                generate_exception(ctx, EXCP_RI);
+                break;
+            }
+        }
+        break;
+    case M16_OPC_LI:
+        {
+            int16_t imm = (uint8_t) ctx->opcode;
+
+            gen_arith_imm(env, ctx, OPC_ADDIU, rx, 0, imm);
+        }
+        break;
+    case M16_OPC_CMPI:
+        {
+            int16_t imm = (uint8_t) ctx->opcode;
+
+            gen_logic_imm(env, OPC_XORI, 24, rx, imm);
+        }
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_SD:
+        check_mips_64(ctx);
+        gen_ldst(ctx, OPC_SD, ry, rx, offset << 3);
+        break;
+#endif
+    case M16_OPC_LB:
+        gen_ldst(ctx, OPC_LB, ry, rx, offset);
+        break;
+    case M16_OPC_LH:
+        gen_ldst(ctx, OPC_LH, ry, rx, offset << 1);
+        break;
+    case M16_OPC_LWSP:
+        gen_ldst(ctx, OPC_LW, rx, 29, ((uint8_t)ctx->opcode) << 2);
+        break;
+    case M16_OPC_LW:
+        gen_ldst(ctx, OPC_LW, ry, rx, offset << 2);
+        break;
+    case M16_OPC_LBU:
+        gen_ldst(ctx, OPC_LBU, ry, rx, offset);
+        break;
+    case M16_OPC_LHU:
+        gen_ldst(ctx, OPC_LHU, ry, rx, offset << 1);
+        break;
+    case M16_OPC_LWPC:
+        gen_ldst(ctx, OPC_LWPC, rx, 0, ((uint8_t)ctx->opcode) << 2);
+        break;
+#if defined (TARGET_MIPS64)
+    case M16_OPC_LWU:
+        check_mips_64(ctx);
+        gen_ldst(ctx, OPC_LWU, ry, rx, offset << 2);
+        break;
+#endif
+    case M16_OPC_SB:
+        gen_ldst(ctx, OPC_SB, ry, rx, offset);
+        break;
+    case M16_OPC_SH:
+        gen_ldst(ctx, OPC_SH, ry, rx, offset << 1);
+        break;
+    case M16_OPC_SWSP:
+        gen_ldst(ctx, OPC_SW, rx, 29, ((uint8_t)ctx->opcode) << 2);
+        break;
+    case M16_OPC_SW:
+        gen_ldst(ctx, OPC_SW, ry, rx, offset << 2);
+        break;
+    case M16_OPC_RRR:
+        {
+            int rz = xlat((ctx->opcode >> 2) & 0x7);
+            int mips32_op;
+
+            switch (ctx->opcode & 0x3) {
+            case RRR_ADDU:
+                mips32_op = OPC_ADDU;
+                break;
+            case RRR_SUBU:
+                mips32_op = OPC_SUBU;
+                break;
+#if defined(TARGET_MIPS64)
+            case RRR_DADDU:
+                mips32_op = OPC_DADDU;
+                check_mips_64(ctx);
+                break;
+            case RRR_DSUBU:
+                mips32_op = OPC_DSUBU;
+                check_mips_64(ctx);
+                break;
+#endif
+            default:
+                generate_exception(ctx, EXCP_RI);
+                goto done;
+            }
+
+            gen_arith(env, ctx, mips32_op, rz, rx, ry);
+        done:
+            ;
+        }
+        break;
+    case M16_OPC_RR:
+        switch (op1) {
+        case RR_JR:
+            {
+                int nd = (ctx->opcode >> 7) & 0x1;
+                int link = (ctx->opcode >> 6) & 0x1;
+                int ra = (ctx->opcode >> 5) & 0x1;
+
+                if (link) {
+                    op = nd ? OPC_JALRC : OPC_JALR;
+                } else {
+                    op = OPC_JR;
+                }
+
+                gen_compute_branch(ctx, op, 2, ra ? 31 : rx, 31, 0);
+                if (!nd) {
+                    *is_branch = 1;
+                }
+            }
+            break;
+        case RR_SDBBP:
+            /* XXX: not clear which exception should be raised
+             *      when in debug mode...
+             */
+            check_insn(env, ctx, ISA_MIPS32);
+            if (!(ctx->hflags & MIPS_HFLAG_DM)) {
+                generate_exception(ctx, EXCP_DBp);
+            } else {
+                generate_exception(ctx, EXCP_DBp);
+            }
+            break;
+        case RR_SLT:
+            gen_slt(env, OPC_SLT, 24, rx, ry);
+            break;
+        case RR_SLTU:
+            gen_slt(env, OPC_SLTU, 24, rx, ry);
+            break;
+        case RR_BREAK:
+            generate_exception(ctx, EXCP_BREAK);
+            break;
+        case RR_SLLV:
+            gen_shift(env, ctx, OPC_SLLV, ry, rx, ry);
+            break;
+        case RR_SRLV:
+            gen_shift(env, ctx, OPC_SRLV, ry, rx, ry);
+            break;
+        case RR_SRAV:
+            gen_shift(env, ctx, OPC_SRAV, ry, rx, ry);
+            break;
+#if defined (TARGET_MIPS64)
+        case RR_DSRL:
+            check_mips_64(ctx);
+            gen_shift_imm(env, ctx, OPC_DSRL, ry, ry, sa);
+            break;
+#endif
+        case RR_CMP:
+            gen_logic(env, OPC_XOR, 24, rx, ry);
+            break;
+        case RR_NEG:
+            gen_arith(env, ctx, OPC_SUBU, rx, 0, ry);
+            break;
+        case RR_AND:
+            gen_logic(env, OPC_AND, rx, rx, ry);
+            break;
+        case RR_OR:
+            gen_logic(env, OPC_OR, rx, rx, ry);
+            break;
+        case RR_XOR:
+            gen_logic(env, OPC_XOR, rx, rx, ry);
+            break;
+        case RR_NOT:
+            gen_logic(env, OPC_NOR, rx, ry, 0);
+            break;
+        case RR_MFHI:
+            gen_HILO(ctx, OPC_MFHI, rx);
+            break;
+        case RR_CNVT:
+            switch (cnvt_op) {
+            case RR_RY_CNVT_ZEB:
+                tcg_gen_ext8u_tl(cpu_gpr[rx], cpu_gpr[rx]);
+                break;
+            case RR_RY_CNVT_ZEH:
+                tcg_gen_ext16u_tl(cpu_gpr[rx], cpu_gpr[rx]);
+                break;
+            case RR_RY_CNVT_SEB:
+                tcg_gen_ext8s_tl(cpu_gpr[rx], cpu_gpr[rx]);
+                break;
+            case RR_RY_CNVT_SEH:
+                tcg_gen_ext16s_tl(cpu_gpr[rx], cpu_gpr[rx]);
+                break;
+#if defined (TARGET_MIPS64)
+            case RR_RY_CNVT_ZEW:
+                check_mips_64(ctx);
+                tcg_gen_ext32u_tl(cpu_gpr[rx], cpu_gpr[rx]);
+                break;
+            case RR_RY_CNVT_SEW:
+                check_mips_64(ctx);
+                tcg_gen_ext32s_tl(cpu_gpr[rx], cpu_gpr[rx]);
+                break;
+#endif
+            default:
+                generate_exception(ctx, EXCP_RI);
+                break;
+            }
+            break;
+        case RR_MFLO:
+            gen_HILO(ctx, OPC_MFLO, rx);
+            break;
+#if defined (TARGET_MIPS64)
+        case RR_DSRA:
+            check_mips_64(ctx);
+            gen_shift_imm(env, ctx, OPC_DSRA, ry, ry, sa);
+            break;
+        case RR_DSLLV:
+            check_mips_64(ctx);
+            gen_shift(env, ctx, OPC_DSLLV, ry, rx, ry);
+            break;
+        case RR_DSRLV:
+            check_mips_64(ctx);
+            gen_shift(env, ctx, OPC_DSRLV, ry, rx, ry);
+            break;
+        case RR_DSRAV:
+            check_mips_64(ctx);
+            gen_shift(env, ctx, OPC_DSRAV, ry, rx, ry);
+            break;
+#endif
+        case RR_MULT:
+            gen_muldiv(ctx, OPC_MULT, rx, ry);
+            break;
+        case RR_MULTU:
+            gen_muldiv(ctx, OPC_MULTU, rx, ry);
+            break;
+        case RR_DIV:
+            gen_muldiv(ctx, OPC_DIV, rx, ry);
+            break;
+        case RR_DIVU:
+            gen_muldiv(ctx, OPC_DIVU, rx, ry);
+            break;
+#if defined (TARGET_MIPS64)
+        case RR_DMULT:
+            check_mips_64(ctx);
+            gen_muldiv(ctx, OPC_DMULT, rx, ry);
+            break;
+        case RR_DMULTU:
+            check_mips_64(ctx);
+            gen_muldiv(ctx, OPC_DMULTU, rx, ry);
+            break;
+        case RR_DDIV:
+            check_mips_64(ctx);
+            gen_muldiv(ctx, OPC_DDIV, rx, ry);
+            break;
+        case RR_DDIVU:
+            check_mips_64(ctx);
+            gen_muldiv(ctx, OPC_DDIVU, rx, ry);
+            break;
+#endif
+        default:
+            generate_exception(ctx, EXCP_RI);
+            break;
+        }
+        break;
+    case M16_OPC_EXTEND:
+        decode_extended_mips16_opc(env, ctx, is_branch);
+        n_bytes = 4;
+        break;
+#if defined(TARGET_MIPS64)
+    case M16_OPC_I64:
+        funct = (ctx->opcode >> 8) & 0x7;
+        decode_i64_mips16(env, ctx, ry, funct, offset, 0);
+        break;
+#endif
+    default:
+        generate_exception(ctx, EXCP_RI);
+        break;
+    }
+
+    return n_bytes;
+}
+
 /* SmartMIPS extension to MIPS32 */
 
 #if defined(TARGET_MIPS64)
@@ -8384,7 +9432,10 @@ static void decode_opc (CPUState *env, DisasContext *ctx, int *is_branch)
 #endif
     case OPC_JALX:
         check_insn(env, ctx, ASE_MIPS16);
-        /* MIPS16: Not implemented. */
+        offset = (int32_t)(ctx->opcode & 0x3FFFFFF) << 2;
+        gen_compute_branch(ctx, op, 4, rs, rt, offset);
+        *is_branch = 1;
+        break;
     case OPC_MDMX:
         check_insn(env, ctx, ASE_MDMX);
         /* MDMX: Not implemented. */
@@ -8469,10 +9520,13 @@ gen_intermediate_code_internal (CPUState *env, TranslationBlock *tb,
             gen_io_start();
 
         is_branch = 0;
-        if (ctx.isa_mode == 0) {
+        if (!(ctx.hflags & MIPS_HFLAG_M16)) {
             ctx.opcode = ldl_code(ctx.pc);
             insn_bytes = 4;
             decode_opc(env, &ctx, &is_branch);
+        } else if (env->insn_flags & ASE_MIPS16) {
+            ctx.opcode = lduw_code(ctx.pc);
+            insn_bytes = decode_mips16_opc(env, &ctx, &is_branch);
         } else {
             generate_exception(&ctx, EXCP_RI);
             break;