diff --git a/src/main/scala/rocket/CustomInstructions.scala b/src/main/scala/rocket/CustomInstructions.scala
index 8ffb5e16a9..b4cada00be 100644
--- a/src/main/scala/rocket/CustomInstructions.scala
+++ b/src/main/scala/rocket/CustomInstructions.scala
@@ -10,6 +10,30 @@ object CustomInstructions {
   def CEASE              = BitPat("b00110000010100000000000001110011")
   def CFLUSH_D_L1        = BitPat("b111111000000?????000000001110011")
   def CDISCARD_D_L1      = BitPat("b111111000010?????000000001110011")
+  def CUSTOM0            = BitPat("b?????????????????000?????0001011")
+  def CUSTOM0_RS1        = BitPat("b?????????????????010?????0001011")
+  def CUSTOM0_RS1_RS2    = BitPat("b?????????????????011?????0001011")
+  def CUSTOM0_RD         = BitPat("b?????????????????100?????0001011")
+  def CUSTOM0_RD_RS1     = BitPat("b?????????????????110?????0001011")
+  def CUSTOM0_RD_RS1_RS2 = BitPat("b?????????????????111?????0001011")
+  def CUSTOM1            = BitPat("b?????????????????000?????0101011")
+  def CUSTOM1_RS1        = BitPat("b?????????????????010?????0101011")
+  def CUSTOM1_RS1_RS2    = BitPat("b?????????????????011?????0101011")
+  def CUSTOM1_RD         = BitPat("b?????????????????100?????0101011")
+  def CUSTOM1_RD_RS1     = BitPat("b?????????????????110?????0101011")
+  def CUSTOM1_RD_RS1_RS2 = BitPat("b?????????????????111?????0101011")
+  def CUSTOM2            = BitPat("b?????????????????000?????1011011")
+  def CUSTOM2_RS1        = BitPat("b?????????????????010?????1011011")
+  def CUSTOM2_RS1_RS2    = BitPat("b?????????????????011?????1011011")
+  def CUSTOM2_RD         = BitPat("b?????????????????100?????1011011")
+  def CUSTOM2_RD_RS1     = BitPat("b?????????????????110?????1011011")
+  def CUSTOM2_RD_RS1_RS2 = BitPat("b?????????????????111?????1011011")
+  def CUSTOM3            = BitPat("b?????????????????000?????1111011")
+  def CUSTOM3_RS1        = BitPat("b?????????????????010?????1111011")
+  def CUSTOM3_RS1_RS2    = BitPat("b?????????????????011?????1111011")
+  def CUSTOM3_RD         = BitPat("b?????????????????100?????1111011")
+  def CUSTOM3_RD_RS1     = BitPat("b?????????????????110?????1111011")
+  def CUSTOM3_RD_RS1_RS2 = BitPat("b?????????????????111?????1111011")
 }
 
 object CustomCSRs {