diff --git a/src/constants.nim b/src/constants.nim
index 7b50cadd5..433b6dba2 100644
--- a/src/constants.nim
+++ b/src/constants.nim
@@ -111,7 +111,7 @@ let
   GAS_COINBASE* =                 20.i256
   GAS_SLOAD_COST* =               20.i256
   GAS_SELF_DESTRUCT_COST* =       5_000.i256
-
+  GAS_IN_HANDLER* =               0.i256 # to be calculated in handler
   REFUNDS_CLEAR* =                15_000.i256
   
   GAS_SELF_DESTRUCT* =            0.i256
diff --git a/src/logic/logging_ops.nim b/src/logic/logging_ops.nim
new file mode 100644
index 000000000..b36b24528
--- /dev/null
+++ b/src/logic/logging_ops.nim
@@ -0,0 +1,64 @@
+import
+  strformat, macros,
+  ../constants, ../errors, ../computation, .. / vm / [stack, memory, gas_meter, message], .. / utils / bytes, bigints
+
+{.this: computation.}
+{.experimental.}
+
+using
+  computation: var BaseComputation
+
+macro logXX(topicCount: static[int]): untyped =
+  if topicCount < 0 or topicCount > 4:
+    error(&"Invalid log topic size {topicCount}  Must be 0, 1, 2, 3, or 4")
+    return
+
+  let name = ident(&"log{topicCount}")
+  let computation = ident("computation")
+  let topics = ident("topics")
+  let topicsTuple = ident("topicsTuple")
+  let size = ident("size")
+  let memStartPosition = ident("memStartPosition")
+  result = quote:
+    proc `name`*(`computation`: var BaseComputation) =
+      let (`memStartPosition`, `size`) = `computation`.stack.popInt(2)
+      var `topics`: seq[Int256]
+
+  var topicCode: NimNode
+  if topicCount == 0:
+    topicCode = quote:
+      `topics` = @[]
+  elif topicCount > 1:
+    topicCode = quote:
+      let `topicsTuple` = `computation`.stack.popInt(`topicCount`)
+    topicCode = nnkStmtList.newTree(topicCode)
+    for z in 0 ..< topicCount:
+      let topicPush = quote:
+        `topics`.add(`topicsTuple`[`z`])
+      topicCode.add(topicPush)
+  else:
+    topicCode = quote:
+      `topics` = @[`computation`.stack.popInt()]
+
+  result.body.add(topicCode)
+
+  let logicCode = quote:
+    let dataGasCost = constants.GAS_LOG_DATA * `size`
+    let topicGasCost = constants.GAS_LOG_TOPIC * `topicCount`.i256
+    let totalGasCost = dataGasCost + topicGasCost
+    `computation`.gasMeter.consumeGas(totalGasCost, reason="Log topic and data gas cost")
+    `computation`.extendMemory(`memStartPosition`, `size`)
+    let logData = `computation`.memory.read(`memStartPosition`, `size`).toCString
+    `computation`.addLogEntry(
+        account=`computation`.msg.storageAddress,
+        topics=`topics`,
+        data=log_data)
+
+  result.body.add(logicCode)
+  # echo result.repr
+
+logXX(0)
+logXX(1)
+logXX(2)
+logXX(3)
+logXX(4)
diff --git a/src/runner.nim b/src/runner.nim
index 1b1cda394..a903b86b1 100644
--- a/src/runner.nim
+++ b/src/runner.nim
@@ -88,11 +88,9 @@ var opcodes = initOpcodes:
   Op.Stop:          GAS_ZERO            stop
 
 
-  # Op.Log0:          GAS_LOG             log0
-  # Op.Log1:          2 * GAS_LOG         log1
-  # Op.Log2:          3 * GAS_LOG         log2
-  # Op.Log3:          4 * GAS_LOG         log3
-  # Op.Log4:          5 * GAS_LOG         log4
+
+  # logging
+  0..4 Op.LogXX:    GAS_IN_HANDLER      logXX
 
   # Op.Create:        GAS_CREATE          create
   # Op.Call:          0.i256              callOp