diff --git a/tcg/riscv/tcg-target.inc.c b/tcg/riscv/tcg-target.inc.c
index 6c969e3973..f853d01803 100644
--- a/tcg/riscv/tcg-target.inc.c
+++ b/tcg/riscv/tcg-target.inc.c
@@ -116,3 +116,171 @@ static const int tcg_target_call_oarg_regs[] = {
     TCG_REG_A0,
     TCG_REG_A1,
 };
+
+#define TCG_CT_CONST_ZERO  0x100
+#define TCG_CT_CONST_S12   0x200
+#define TCG_CT_CONST_N12   0x400
+#define TCG_CT_CONST_M12   0x800
+
+static inline tcg_target_long sextreg(tcg_target_long val, int pos, int len)
+{
+    if (TCG_TARGET_REG_BITS == 32) {
+        return sextract32(val, pos, len);
+    } else {
+        return sextract64(val, pos, len);
+    }
+}
+
+/* parse target specific constraints */
+static const char *target_parse_constraint(TCGArgConstraint *ct,
+                                           const char *ct_str, TCGType type)
+{
+    switch (*ct_str++) {
+    case 'r':
+        ct->ct |= TCG_CT_REG;
+        ct->u.regs = 0xffffffff;
+        break;
+    case 'L':
+        /* qemu_ld/qemu_st constraint */
+        ct->ct |= TCG_CT_REG;
+        ct->u.regs = 0xffffffff;
+        /* qemu_ld/qemu_st uses TCG_REG_TMP0 */
+#if defined(CONFIG_SOFTMMU)
+        tcg_regset_reset_reg(ct->u.regs, tcg_target_call_iarg_regs[0]);
+        tcg_regset_reset_reg(ct->u.regs, tcg_target_call_iarg_regs[1]);
+        tcg_regset_reset_reg(ct->u.regs, tcg_target_call_iarg_regs[2]);
+        tcg_regset_reset_reg(ct->u.regs, tcg_target_call_iarg_regs[3]);
+        tcg_regset_reset_reg(ct->u.regs, tcg_target_call_iarg_regs[4]);
+#endif
+        break;
+    case 'I':
+        ct->ct |= TCG_CT_CONST_S12;
+        break;
+    case 'N':
+        ct->ct |= TCG_CT_CONST_N12;
+        break;
+    case 'M':
+        ct->ct |= TCG_CT_CONST_M12;
+        break;
+    case 'Z':
+        /* we can use a zero immediate as a zero register argument. */
+        ct->ct |= TCG_CT_CONST_ZERO;
+        break;
+    default:
+        return NULL;
+    }
+    return ct_str;
+}
+
+/* test if a constant matches the constraint */
+static int tcg_target_const_match(tcg_target_long val, TCGType type,
+                                  const TCGArgConstraint *arg_ct)
+{
+    int ct = arg_ct->ct;
+    if (ct & TCG_CT_CONST) {
+        return 1;
+    }
+    if ((ct & TCG_CT_CONST_ZERO) && val == 0) {
+        return 1;
+    }
+    if ((ct & TCG_CT_CONST_S12) && val == sextreg(val, 0, 12)) {
+        return 1;
+    }
+    if ((ct & TCG_CT_CONST_N12) && -val == sextreg(-val, 0, 12)) {
+        return 1;
+    }
+    if ((ct & TCG_CT_CONST_M12) && val >= -0xfff && val <= 0xfff) {
+        return 1;
+    }
+    return 0;
+}
+
+/*
+ * RISC-V Base ISA opcodes (IM)
+ */
+
+typedef enum {
+    OPC_ADD = 0x33,
+    OPC_ADDI = 0x13,
+    OPC_AND = 0x7033,
+    OPC_ANDI = 0x7013,
+    OPC_AUIPC = 0x17,
+    OPC_BEQ = 0x63,
+    OPC_BGE = 0x5063,
+    OPC_BGEU = 0x7063,
+    OPC_BLT = 0x4063,
+    OPC_BLTU = 0x6063,
+    OPC_BNE = 0x1063,
+    OPC_DIV = 0x2004033,
+    OPC_DIVU = 0x2005033,
+    OPC_JAL = 0x6f,
+    OPC_JALR = 0x67,
+    OPC_LB = 0x3,
+    OPC_LBU = 0x4003,
+    OPC_LD = 0x3003,
+    OPC_LH = 0x1003,
+    OPC_LHU = 0x5003,
+    OPC_LUI = 0x37,
+    OPC_LW = 0x2003,
+    OPC_LWU = 0x6003,
+    OPC_MUL = 0x2000033,
+    OPC_MULH = 0x2001033,
+    OPC_MULHSU = 0x2002033,
+    OPC_MULHU = 0x2003033,
+    OPC_OR = 0x6033,
+    OPC_ORI = 0x6013,
+    OPC_REM = 0x2006033,
+    OPC_REMU = 0x2007033,
+    OPC_SB = 0x23,
+    OPC_SD = 0x3023,
+    OPC_SH = 0x1023,
+    OPC_SLL = 0x1033,
+    OPC_SLLI = 0x1013,
+    OPC_SLT = 0x2033,
+    OPC_SLTI = 0x2013,
+    OPC_SLTIU = 0x3013,
+    OPC_SLTU = 0x3033,
+    OPC_SRA = 0x40005033,
+    OPC_SRAI = 0x40005013,
+    OPC_SRL = 0x5033,
+    OPC_SRLI = 0x5013,
+    OPC_SUB = 0x40000033,
+    OPC_SW = 0x2023,
+    OPC_XOR = 0x4033,
+    OPC_XORI = 0x4013,
+
+#if TCG_TARGET_REG_BITS == 64
+    OPC_ADDIW = 0x1b,
+    OPC_ADDW = 0x3b,
+    OPC_DIVUW = 0x200503b,
+    OPC_DIVW = 0x200403b,
+    OPC_MULW = 0x200003b,
+    OPC_REMUW = 0x200703b,
+    OPC_REMW = 0x200603b,
+    OPC_SLLIW = 0x101b,
+    OPC_SLLW = 0x103b,
+    OPC_SRAIW = 0x4000501b,
+    OPC_SRAW = 0x4000503b,
+    OPC_SRLIW = 0x501b,
+    OPC_SRLW = 0x503b,
+    OPC_SUBW = 0x4000003b,
+#else
+    /* Simplify code throughout by defining aliases for RV32.  */
+    OPC_ADDIW = OPC_ADDI,
+    OPC_ADDW = OPC_ADD,
+    OPC_DIVUW = OPC_DIVU,
+    OPC_DIVW = OPC_DIV,
+    OPC_MULW = OPC_MUL,
+    OPC_REMUW = OPC_REMU,
+    OPC_REMW = OPC_REM,
+    OPC_SLLIW = OPC_SLLI,
+    OPC_SLLW = OPC_SLL,
+    OPC_SRAIW = OPC_SRAI,
+    OPC_SRAW = OPC_SRA,
+    OPC_SRLIW = OPC_SRLI,
+    OPC_SRLW = OPC_SRL,
+    OPC_SUBW = OPC_SUB,
+#endif
+
+    OPC_FENCE = 0x0000000f,
+} RISCVInsn;
