diff --git a/lua/wire/cpulib.lua b/lua/wire/cpulib.lua
index 0dce233..2e8690d 100644
--- a/lua/wire/cpulib.lua
+++ b/lua/wire/cpulib.lua
@@ -1000,6 +1000,8 @@ CPU(137, "EXTRETP",       1,  10.00,    R0,        "PTBL",  "",      "Set PTBL,
 CPU(140, "EXTRETA",       0,  11.00,    R0,        "",      "",      "Return from an external interrupt and restore R0-R31 registers")
 CPU(141, "EXTRETPA",      1,  11.00,    R0,        "PTBL",  "",      "Set PTBL, then return from an external interrupt with restoring R0-R31 registers")
 ---- Dec 15 -- UNDEFINED ------------------------------------------------------------------------------------------------------------------------
+CPU(150, "STERR",         2,   3.00,    R0,        "X",  "Y",        "Output an external error where X is error number and Y is error parameter")
+CPU(151, "CLERR",         0,   1.00,    R0,        "",    "",        "Clear the external error output")
 ---- Dec 16 -- UNDEFINED ------------------------------------------------------------------------------------------------------------------------
 ---- Dec 17 -- UNDEFINED ------------------------------------------------------------------------------------------------------------------------
 ---- Dec 18 -- UNDEFINED ------------------------------------------------------------------------------------------------------------------------
diff --git a/lua/wire/zvm/zvm_features.lua b/lua/wire/zvm/zvm_features.lua
index 8efa252..e7032c0 100644
--- a/lua/wire/zvm/zvm_features.lua
+++ b/lua/wire/zvm/zvm_features.lua
@@ -645,7 +645,9 @@ function ZVM:ExternalInterrupt(interruptNo)
 end
 
 
-
+function ZVM:MakeErrorCode(code,param) 
+  return code+(param * (10^math.floor(-math.log10(math.abs(param)+1e-12)-1)))
+end
 
 --------------------------------------------------------------------------------
 function ZVM:Interrupt(interruptNo,interruptParameter,isExternal,cascadeInterrupt)
@@ -660,8 +662,7 @@ function ZVM:Interrupt(interruptNo,interruptParameter,isExternal,cascadeInterrup
   self.LADD = interruptParameter or self.XEIP
 
   -- Output an error externally
-  local fractionalParameter = self.LADD * (10^math.floor(-math.log10(math.abs(self.LADD)+1e-12)-1))
-  self:SignalError(fractionalParameter+interruptNo)
+  self:SignalError(self:MakeErrorCode(interruptNo,self.LADD))
 
   -- Check if interrupts handling is enabled
   if self.IF == 1 then
diff --git a/lua/wire/zvm/zvm_opcodes.lua b/lua/wire/zvm/zvm_opcodes.lua
index 28a44ce..069aea8 100644
--- a/lua/wire/zvm/zvm_opcodes.lua
+++ b/lua/wire/zvm/zvm_opcodes.lua
@@ -1221,6 +1221,14 @@ ZVM.OpcodeTable[141] = function(self) --EXTRETPA
 end
 
 
+ZVM.OpcodeTable[150] = function(self) -- STERR
+    self:Dyn_Emit("VM:SignalError(VM:MakeErrorCode($1,$2))")
+end
+
+ZVM.OpcodeTable[151] = function(self) -- CLERR
+    self:Dyn_Emit("VM:SignalError(0)")
+end
+
 --------------------------------------------------------------------------------
 ZVM.OpcodeTable[250] = function(self)  --VADD
   self:Dyn_Emit("if VM.VMODE == 2 then")