diff --git a/proto/runtime/src/main/kotlin/CodedInputStream.kt b/proto/runtime/src/main/kotlin/CodedInputStream.kt
index bbf2e58de41..1ba96e47970 100644
--- a/proto/runtime/src/main/kotlin/CodedInputStream.kt
+++ b/proto/runtime/src/main/kotlin/CodedInputStream.kt
@@ -192,13 +192,13 @@ class CodedInputStream(val buffer: ByteArray) {
     // reads zig-zag encoded integer not larger than 32-bit long
     fun readZigZag32NoTag(): Int {
         val value = readInt32NoTag()
-        return (value shr 1) xor (-(value and 1))   // bit magic for decoding zig-zag number
+        return (value ushr 1) xor (-(value and 1))   // bit magic for decoding zig-zag number
     }
 
     // reads zig-zag encoded integer not larger than 64-bit long
     fun readZigZag64NoTag(): Long {
         val value = readInt64NoTag()
-        return (value shr 1) xor (-(value and 1L))  // bit magic for decoding zig-zag number
+        return (value ushr 1) xor (-(value and 1L))  // bit magic for decoding zig-zag number
     }
 
     // checks if at least one more byte can be read from underlying input stream
diff --git a/proto/runtime/src/main/kotlin/CodedOutputStream.kt b/proto/runtime/src/main/kotlin/CodedOutputStream.kt
index 69b9efff821..7470239a2ba 100644
--- a/proto/runtime/src/main/kotlin/CodedOutputStream.kt
+++ b/proto/runtime/src/main/kotlin/CodedOutputStream.kt
@@ -11,7 +11,7 @@ class CodedOutputStream(val buffer: ByteArray) {
 
     fun writeTag(fieldNumber: Int, type: WireType) {
         val tag = (fieldNumber shl 3) or type.id
-        writeInt32NoTag(tag)
+        writeRawVarint32(tag)
     }
 
     fun writeInt32(fieldNumber: Int, value: Int) {
@@ -19,15 +19,24 @@ class CodedOutputStream(val buffer: ByteArray) {
         writeInt32NoTag(value)
     }
 
+    fun writeInt32NoTag(value: Int) {
+        if (value < 0) {    // sign-extend negative values
+            writeRawVarint64(value.toLong())
+            return
+        }
+        writeRawVarint32(value)
+    }
+
     // Note that unsigned integer types are stored as their signed counterparts with top bit
     // simply stored in the sign bit - similar to Java's protobuf implementation. Hence, all
     // methods, writing unsigned ints simply redirect call to corresponding signed-writing method
     fun writeUInt32(fieldNumber: Int, value: Int) {
-        writeInt32(fieldNumber, value)
+        writeTag(fieldNumber, WireType.VARINT)
+        writeUInt32NoTag(value)
     }
 
     fun writeUInt32NoTag(value: Int) {
-        writeInt32NoTag(value)
+        writeRawVarint32(value)
     }
 
     fun writeInt64(fieldNumber: Int, value: Long) {
@@ -35,13 +44,18 @@ class CodedOutputStream(val buffer: ByteArray) {
         writeInt64NoTag(value)
     }
 
+    fun writeInt64NoTag(value: Long) {
+        writeRawVarint64(value)
+    }
+
     // See notes on unsigned integers implementation above
     fun writeUInt64(fieldNumber: Int, value: Long) {
-        writeInt64(fieldNumber, value)
+        writeTag(fieldNumber, WireType.VARINT)
+        writeUInt64NoTag(value)
     }
 
     fun writeUInt64NoTag(value: Long) {
-        writeInt64NoTag(value)
+        writeRawVarint64(value)
     }
 
     fun writeBool(fieldNumber: Int, value: Boolean) {
@@ -50,7 +64,7 @@ class CodedOutputStream(val buffer: ByteArray) {
     }
 
     fun writeBoolNoTag(value: Boolean) {
-        writeInt32NoTag(if (value) 1 else 0)
+        writeRawVarint32(if (value) 1 else 0)
     }
 
     // Writing enums is like writing one int32 number. Caller is responsible for converting enum-object to ordinal
@@ -60,7 +74,7 @@ class CodedOutputStream(val buffer: ByteArray) {
     }
 
     fun writeEnumNoTag(value: Int) {
-        writeInt32NoTag(value)
+        writeRawVarint32(value)
     }
 
     fun writeSInt32(fieldNumber: Int, value: Int) {
@@ -69,7 +83,7 @@ class CodedOutputStream(val buffer: ByteArray) {
     }
 
     fun writeSInt32NoTag(value: Int) {
-        writeInt32NoTag((value shl 1) xor (value shr 31))
+        writeUInt32NoTag((value shl 1) xor (value shr 31))
     }
 
     fun writeSInt64(fieldNumber: Int, value: Long) {
@@ -78,7 +92,7 @@ class CodedOutputStream(val buffer: ByteArray) {
     }
 
     fun writeSInt64NoTag(value: Long) {
-        writeInt64NoTag((value shl 1) xor (value shr 63))
+        writeUInt64NoTag((value shl 1) xor (value shr 63))
     }
 
     fun writeBytes(fieldNumber: Int, value: ByteArray) {
@@ -90,7 +104,7 @@ class CodedOutputStream(val buffer: ByteArray) {
     }
 
     fun writeBytesNoTag(value: ByteArray) {
-        writeInt32NoTag(value.size)
+        writeRawVarint32(value.size)
         output.write(value)
     }
 
@@ -99,12 +113,7 @@ class CodedOutputStream(val buffer: ByteArray) {
      *  Then she/he can re-use low-level methods for operating with raw values, that are not annotated with Protobuf tags.
      */
 
-    fun writeInt32NoTag(value: Int) {
-        if (value < 0) {
-            writeInt64NoTag(value.toLong())
-            return
-        }
-
+    fun writeRawVarint32(value: Int) {
         var curValue: Int = value
 
         // we have at most 32 information bits. With overhead of 1 bit per 7 bits we need at most 5 bytes for encoding
@@ -129,7 +138,7 @@ class CodedOutputStream(val buffer: ByteArray) {
         output.write(res, 0, resSize)
     }
 
-    fun writeInt64NoTag(value: Long) {
+    fun writeRawVarint64(value: Long) {
         var curValue: Long = value
 
         // we have at most 64 information bits. With overhead of 1 bit per 7 bits we need at most 10 bytes for encoding
diff --git a/proto/runtime/src/main/kotlin/WireFormat.kt b/proto/runtime/src/main/kotlin/WireFormat.kt
index ff1ba920f68..d43c6e37003 100644
--- a/proto/runtime/src/main/kotlin/WireFormat.kt
+++ b/proto/runtime/src/main/kotlin/WireFormat.kt
@@ -23,25 +23,22 @@ object WireFormat {
     }
 
     fun getVarint32Size(value: Int): Int {
-        if (value < 0) {
-            return getVarint64Size(value.toLong())
-        }
         var curValue = value
         var size = 0
-        while (curValue != 0) {
+        do {
             size += 1
             curValue = curValue ushr VARINT_INFO_BITS_COUNT
-        }
+        } while (curValue != 0)
         return size
     }
 
     fun getVarint64Size(value: Long): Int {
         var curValue = value
         var size = 0
-        while (curValue != 0L) {
+        do {
             size += 1
             curValue = curValue ushr VARINT_INFO_BITS_COUNT
-        }
+        }while (curValue != 0L)
         return size
     }
 
@@ -54,15 +51,18 @@ object WireFormat {
     }
 
     fun getInt32Size(fieldNumber: Int, value: Int): Int {
-        return getTagSize(fieldNumber, WireType.VARINT) + getVarint32Size(value)
+        return getTagSize(fieldNumber, WireType.VARINT) + getInt32SizeNoTag(value)
     }
 
     fun getInt32SizeNoTag(value: Int): Int {
+        if (value < 0) {
+            return getVarint64Size(value.toLong())
+        }
         return getVarint32Size(value)
     }
 
     fun getUInt32Size(fieldNumber: Int, value: Int): Int {
-        return getInt32Size(fieldNumber, value)
+        return getTagSize(fieldNumber, WireType.VARINT) + getUInt32SizeNoTag(value)
     }
 
     fun getUInt32SizeNoTag(value: Int): Int {
@@ -70,7 +70,7 @@ object WireFormat {
     }
 
     fun getInt64Size(fieldNumber: Int, value: Long): Int {
-        return getTagSize(fieldNumber, WireType.VARINT) + getVarint64Size(value)
+        return getTagSize(fieldNumber, WireType.VARINT) + getUInt64SizeNoTag(value)
     }
 
     fun getInt64SizeNoTag(value: Long): Int {