diff --git a/src/devices/cpu/ie15/ie15dasm.cpp b/src/devices/cpu/ie15/ie15dasm.cpp
index 536497b9db0..d18fd3c81a6 100644
--- a/src/devices/cpu/ie15/ie15dasm.cpp
+++ b/src/devices/cpu/ie15/ie15dasm.cpp
@@ -5,7 +5,7 @@
 #define OP(A)   oprom[(A) - PC]
 #define ARG(A)  opram[(A) - PC]
 
-CPU_DISASSEMBLE( ie15 )
+static offs_t internal_disasm_ie15(cpu_device *device, std::ostream &stream, offs_t pc, const uint8_t *oprom, const uint8_t *opram, int options)
 {
 	uint32_t flags = 0;
 	uint8_t op;
@@ -15,112 +15,122 @@ CPU_DISASSEMBLE( ie15 )
 	switch (op & 0xf0)
 	{
 		case 0x00:
-			sprintf (buffer,"add  r%d", op & 0x0f);
+			util::stream_format(stream, "add  r%d", op & 0x0f);
 			break;
 		case 0x10:
-			sprintf (buffer,"jmp  $%04x", (((op & 0x0f) << 8) | ARG(pc)) + 1);
+			util::stream_format(stream, "jmp  $%04x", (((op & 0x0f) << 8) | ARG(pc)) + 1);
 			pc+=1;
 			break;
 		case 0x20:
-			sprintf (buffer,"ldc  r%d, #$%02x", (op & 0x0f), ARG(pc));
+			util::stream_format(stream, "ldc  r%d, #$%02x", (op & 0x0f), ARG(pc));
 			pc+=1;
 			break;
 		case 0x30: switch (op)
 		{
 			case 0x30:
-				sprintf (buffer,"lca  #$%02x", ARG(pc));
+				util::stream_format(stream, "lca  #$%02x", ARG(pc));
 				pc+=1;
 				break;
 			case 0x33:
-				sprintf (buffer,"ral");
+				util::stream_format(stream, "ral");
 				break;
 			case 0x35:
-				sprintf (buffer,"rar");
+				util::stream_format(stream, "rar");
 				break;
 			default:
-				sprintf (buffer,"illegal");
+				util::stream_format(stream, "illegal");
 				break;
 		};
 		break;
 		case 0x40:
-			sprintf (buffer,"dsr  r%d", op & 0x0f);
+			util::stream_format(stream, "dsr  r%d", op & 0x0f);
 			break;
 		case 0x50: switch (op)
 		{
 			case 0x50:
-				sprintf (buffer,"isn");
+				util::stream_format(stream, "isn");
 				break;
 			case 0x51:
-				sprintf (buffer,"inc");
+				util::stream_format(stream, "inc");
 				break;
 			case 0x52:
-				sprintf (buffer,"dsn");
+				util::stream_format(stream, "dsn");
 				break;
 			case 0x58:
-				sprintf (buffer,"ise");
+				util::stream_format(stream, "ise");
 				break;
 			case 0x5a:
-				sprintf (buffer,"dse");
+				util::stream_format(stream, "dse");
 				break;
 			case 0x5b:
-				sprintf (buffer,"dec");
+				util::stream_format(stream, "dec");
 				break;
 			case 0x5d:
-				sprintf (buffer,"com");
+				util::stream_format(stream, "com");
 				break;
 			case 0x5f:
-				sprintf (buffer,"clr");
+				util::stream_format(stream, "clr");
 				break;
 			default:
-				sprintf (buffer,"illegal");
+				util::stream_format(stream, "illegal");
 				break;
 		};
 		break;
 		case 0x60:
-			sprintf (buffer,"lla  #$%02x", op & 0x0f);
+			util::stream_format(stream, "lla  #$%02x", op & 0x0f);
 			break;
 		case 0x70:
-			sprintf (buffer,"jmi  r%d", op & 0x0f);
+			util::stream_format(stream, "jmi  r%d", op & 0x0f);
 			break;
 		case 0x80: switch (op)
 		{
 			case 0x80: case 0x81: case 0x82: case 0x83:
 			case 0x84: case 0x85: case 0x86:
-				sprintf (buffer,"sfc  #%d", op & 0x07);
+				util::stream_format(stream, "sfc  #%d", op & 0x07);
 				break;
 			case 0x87:
-				sprintf (buffer,"skp");
+				util::stream_format(stream, "skp");
 				break;
 			case 0x88: case 0x89: case 0x8a: case 0x8b:
 			case 0x8c: case 0x8d: case 0x8e:
-				sprintf (buffer,"sfs  #%d", op & 0x07);
+				util::stream_format(stream, "sfs  #%d", op & 0x07);
 				break;
 			case 0x8f:
-				sprintf (buffer,"nop");
+				util::stream_format(stream, "nop");
 				break;
 		};
 		break;
 		case 0x90:
-			sprintf (buffer,"and  r%d", op & 0x0f);
+			util::stream_format(stream, "and  r%d", op & 0x0f);
 			break;
 		case 0xa0:
-			sprintf (buffer,"xor  r%d", op & 0x0f);
+			util::stream_format(stream, "xor  r%d", op & 0x0f);
 			break;
 		case 0xb0:
-			sprintf (buffer,"cs   r%d", op & 0x0f);
+			util::stream_format(stream, "cs   r%d", op & 0x0f);
 			break;
 		case 0xc0:
-			sprintf (buffer,"%s  #%d", BIT(op, 3) ? "sfl" : "cfl", op & 0x07);
+			util::stream_format(stream, "%s  #%d", BIT(op, 3) ? "sfl" : "cfl", op & 0x07);
 			break;
 		case 0xd0:
-			sprintf (buffer,"lda  r%d", op & 0x0f);
+			util::stream_format(stream, "lda  r%d", op & 0x0f);
 			break;
 		case 0xe0:
-			sprintf (buffer,"sta  r%d", op & 0x0f);
+			util::stream_format(stream, "sta  r%d", op & 0x0f);
 			break;
 		case 0xf0:
-			sprintf (buffer,"ota  #$%02x", op & 0x0f);
+			util::stream_format(stream, "ota  #$%02x", op & 0x0f);
 			break;
 	}
 	return (pc - PC) | flags | DASMFLAG_SUPPORTED;
 }
+
+
+CPU_DISASSEMBLE(ie15)
+{
+	std::ostringstream stream;
+	offs_t result = internal_disasm_ie15(device, stream, pc, oprom, opram, options);
+	std::string stream_str = stream.str();
+	strcpy(buffer, stream_str.c_str());
+	return result;
+}