diff --git a/src/devices/cpu/8x300/8x300dasm.cpp b/src/devices/cpu/8x300/8x300dasm.cpp
index 562dbaf4693..5b66dbd1f05 100644
--- a/src/devices/cpu/8x300/8x300dasm.cpp
+++ b/src/devices/cpu/8x300/8x300dasm.cpp
@@ -41,9 +41,8 @@ static inline bool is_src_rot(uint16_t opcode)
 		return true;
 }
 
-CPU_DISASSEMBLE( n8x300 )
+static offs_t internal_disasm_n8x300(cpu_device *device, std::ostream &stream, offs_t pc, const uint8_t *oprom, const uint8_t *opram, int options)
 {
-	char tmp[16];
 	unsigned startpc = pc;
 	uint16_t opcode = (oprom[pc - startpc] << 8) | oprom[pc+1 - startpc];
 	uint8_t inst = opcode >> 13;
@@ -53,99 +52,90 @@ CPU_DISASSEMBLE( n8x300 )
 	switch (inst)
 	{
 	case 0x00:
-		sprintf(buffer,"MOVE ");
-		strcat(buffer,reg_names[SRC]);
+		stream << "MOVE " << reg_names[SRC];
 		if(is_rot(opcode))
-			sprintf(tmp,"(%i),",ROTLEN);
+			util::stream_format(stream, "(%i),", ROTLEN);
 		else
-			sprintf(tmp,",%i,",ROTLEN);
-		strcat(buffer,tmp);
-		strcat(buffer,reg_names[DST]);
+			util::stream_format(stream, ",%i,", ROTLEN);
+		stream << reg_names[DST];
 		break;
 	case 0x01:
-		sprintf(buffer,"ADD  ");
-		strcat(buffer,reg_names[SRC]);
+		stream << "ADD  " << reg_names[SRC];
 		if(is_rot(opcode))
-			sprintf(tmp,"(%i),",ROTLEN);
+			util::stream_format(stream, "(%i),", ROTLEN);
 		else
-			sprintf(tmp,",%i,",ROTLEN);
-		strcat(buffer,tmp);
-		strcat(buffer,reg_names[DST]);
+			util::stream_format(stream, ",%i,", ROTLEN);
+		stream << reg_names[DST];
 		break;
 	case 0x02:
-		sprintf(buffer,"AND  ");
-		strcat(buffer,reg_names[SRC]);
+		stream << "AND  " << reg_names[SRC];
 		if(is_rot(opcode))
-			sprintf(tmp,"(%i),",ROTLEN);
+			util::stream_format(stream, "(%i),", ROTLEN);
 		else
-			sprintf(tmp,",%i,",ROTLEN);
-		strcat(buffer,tmp);
-		strcat(buffer,reg_names[DST]);
+			util::stream_format(stream, ",%i,", ROTLEN);
+		stream << reg_names[DST];
 		break;
 	case 0x03:
-		sprintf(buffer,"XOR  ");
-		strcat(buffer,reg_names[SRC]);
+		stream << "XOR  " << reg_names[SRC];
 		if(is_rot(opcode))
-			sprintf(tmp,"(%i),",ROTLEN);
+			util::stream_format(stream, "(%i),", ROTLEN);
 		else
-			sprintf(tmp,",%i,",ROTLEN);
-		strcat(buffer,tmp);
-		strcat(buffer,reg_names[DST]);
+			util::stream_format(stream, ",%i,", ROTLEN);
+		stream << reg_names[DST];
 		break;
 	case 0x04:
-		sprintf(buffer,"XEC  ");
-		strcat(buffer,reg_names[SRC]);
+		stream << "XEC  " << reg_names[SRC];
 		if(is_src_rot(opcode))
 		{
-			sprintf(tmp,",%02XH",IMM8);
-			strcat(buffer,tmp);
+			util::stream_format(stream, ",%02XH", IMM8);
 		}
 		else
 		{
-			sprintf(tmp,",%i",ROTLEN);
-			strcat(buffer,tmp);
-			sprintf(tmp,",%02XH",IMM5);
-			strcat(buffer,tmp);
+			util::stream_format(stream, ",%i", ROTLEN);
+			util::stream_format(stream, ",%02XH", IMM5);
 		}
 		break;
 	case 0x05:
-		sprintf(buffer,"NZT  ");
-		strcat(buffer,reg_names[SRC]);
+		stream << "NZT  " << reg_names[SRC];
 		if(is_src_rot(opcode))
 		{
-			sprintf(tmp,",%02XH",IMM8);
-			strcat(buffer,tmp);
+			util::stream_format(stream, ",%02XH", IMM8);
 		}
 		else
 		{
-			sprintf(tmp,",%i",ROTLEN);
-			strcat(buffer,tmp);
-			sprintf(tmp,",%02XH",IMM5);
-			strcat(buffer,tmp);
+			util::stream_format(stream, ",%i", ROTLEN);
+			util::stream_format(stream, ",%02XH", IMM5);
 		}
 		break;
 	case 0x06:
-		sprintf(buffer,"XMIT ");
+		stream << "XMIT ";
 		if(is_src_rot(opcode))
 		{
-			sprintf(tmp,"%02XH,",IMM8);
-			strcat(buffer,tmp);
-			strcat(buffer,reg_names[SRC]);
+			util::stream_format(stream, "%02XH,", IMM8);
+			stream << reg_names[SRC];
 		}
 		else
 		{
-			sprintf(tmp,"%02XH,",IMM5);
-			strcat(buffer,tmp);
-			strcat(buffer,reg_names[SRC]);
-			sprintf(tmp,",%i",ROTLEN);
-			strcat(buffer,tmp);
+			util::stream_format(stream, "%02XH,", IMM5);
+			stream << reg_names[SRC];
+			util::stream_format(stream, ",%i", ROTLEN);
 		}
 		break;
 	case 0x07:
-		sprintf(buffer,"JMP  %04XH",opcode & 0x1fff);
+		util::stream_format(stream, "JMP  %04XH", opcode & 0x1fff);
 		break;
 	}
 
 
 	return (pc - startpc);
 }
+
+
+CPU_DISASSEMBLE(n8x300)
+{
+	std::ostringstream stream;
+	offs_t result = internal_disasm_n8x300(device, stream, pc, oprom, opram, options);
+	std::string stream_str = stream.str();
+	strcpy(buffer, stream_str.c_str());
+	return result;
+}