diff --git a/target/riscv/translate.c b/target/riscv/translate.c index f19d5cd0c0..30b1b68341 100644 --- a/target/riscv/translate.c +++ b/target/riscv/translate.c @@ -111,6 +111,11 @@ static inline bool has_ext(DisasContext *ctx, uint32_t ext) return ctx->misa_ext & ext; } +static bool always_true_p(DisasContext *ctx __attribute__((__unused__))) +{ + return true; +} + #ifdef TARGET_RISCV32 #define get_xl(ctx) MXL_RV32 #elif defined(CONFIG_USER_ONLY) @@ -855,15 +860,26 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc) static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode) { - /* check for compressed insn */ + /* + * A table with predicate (i.e., guard) functions and decoder functions + * that are tested in-order until a decoder matches onto the opcode. + */ + static const struct { + bool (*guard_func)(DisasContext *); + bool (*decode_func)(DisasContext *, uint32_t); + } decoders[] = { + { always_true_p, decode_insn32 }, + }; + + /* Check for compressed insn */ if (extract16(opcode, 0, 2) != 3) { if (!has_ext(ctx, RVC)) { gen_exception_illegal(ctx); } else { ctx->opcode = opcode; ctx->pc_succ_insn = ctx->base.pc_next + 2; - if (!decode_insn16(ctx, opcode)) { - gen_exception_illegal(ctx); + if (decode_insn16(ctx, opcode)) { + return; } } } else { @@ -873,10 +889,16 @@ static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode) ctx->base.pc_next + 2)); ctx->opcode = opcode32; ctx->pc_succ_insn = ctx->base.pc_next + 4; - if (!decode_insn32(ctx, opcode32)) { - gen_exception_illegal(ctx); + + for (size_t i = 0; i < ARRAY_SIZE(decoders); ++i) { + if (decoders[i].guard_func(ctx) && + decoders[i].decode_func(ctx, opcode32)) { + return; + } } } + + gen_exception_illegal(ctx); } static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)