diff --git a/assert.h b/assert.h
index ea38f1d..31896ea 100644
--- a/assert.h
+++ b/assert.h
@@ -1,20 +1,18 @@
 #pragma once
 
-#if defined(__dreamcast__)
-#include "sh7091/serial.hpp"
-#define print__character serial::character
-#define print__string serial::string
-#define print__integer serial::integer<uint32_t>
-#else
-#error "unknown platform"
-#endif
+#include "printf/printf.h"
+
+#define print__character print_char
+#define print__string print_cstring
+#define print__integer print_integer
 
 #define assert(b)                                                       \
   do {                                                                  \
     if (!(b)) {                                                         \
       print__string(__FILE__);                                          \
       print__character(':');                                            \
-      print__integer(__LINE__, ' ');                                    \
+      print__integer(__LINE__);                                         \
+      print__character(' ');                                            \
       print__string(__func__);                                          \
       print__string(": assertion failed: ");                            \
       print__string(#b);                                                \
diff --git a/printf/printf.c b/printf/printf.c
index cf6e41a..f0a9f22 100644
--- a/printf/printf.c
+++ b/printf/printf.c
@@ -103,6 +103,13 @@ void print_cstring(const char * s)
   }
 }
 
+void print_integer(const int n)
+{
+  char s[16];
+  int offset = unparse_base10(s, n, 0, 0);
+  print_string(s, offset);
+}
+
 void _printf(const char * format, ...)
 {
   va_list args;
@@ -121,7 +128,7 @@ void _printf(const char * format, ...)
         case FORMAT_BASE10_UNSIGNED:
           {
             uint32_t num = va_arg(args, uint32_t);
-            char s[10];
+            char s[16];
             int offset = unparse_base10_unsigned(s, num, ft.pad_length, ft.fill_char);
             print_string(s, offset);
           }
@@ -129,7 +136,7 @@ void _printf(const char * format, ...)
         case FORMAT_BASE10:
           {
             int32_t num = va_arg(args, int32_t);
-            char s[10];
+            char s[16];
             int offset = unparse_base10(s, num, ft.pad_length, ft.fill_char);
             print_string(s, offset);
           }
@@ -137,7 +144,7 @@ void _printf(const char * format, ...)
         case FORMAT_BASE10_64:
           {
             int64_t num = va_arg(args, int64_t);
-            char s[20];
+            char s[16];
             int offset = unparse_base10_64(s, num, ft.pad_length, ft.fill_char);
             print_string(s, offset);
           }
@@ -151,7 +158,7 @@ void _printf(const char * format, ...)
         case FORMAT_BASE16:
           {
             uint32_t num = va_arg(args, uint32_t);
-            char s[8];
+            char s[16];
             int offset = unparse_base16(s, num, ft.pad_length, ft.fill_char);
             print_string(s, offset);
           }
@@ -184,7 +191,7 @@ void _printf(const char * format, ...)
             print_string(s, offset);
             print_char('.');
             int32_t fraction = (int32_t)((num - (float)whole) * 1000.0);
-            offset = unparse_base10_unsigned(s, fraction, 0, 0);
+            offset = unparse_base10_unsigned(s, fraction, 3, '0');
             print_string(s, offset);
           }
           break;
diff --git a/printf/printf.h b/printf/printf.h
index ad80505..d19495f 100644
--- a/printf/printf.h
+++ b/printf/printf.h
@@ -25,6 +25,7 @@ void print_string(const char * s, int length);
 void print_bytes(const uint8_t * s, int length);
 void print_chars(const uint16_t * s, int length);
 void print_cstring(const char * s);
+void print_integer(const int n);
 
 void _printf(const char * format, ...);
 
diff --git a/xm/xm.h b/xm/xm.h
index 912207a..b8bea65 100644
--- a/xm/xm.h
+++ b/xm/xm.h
@@ -4,6 +4,10 @@
 #include <assert.h>
 #include <stddef.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct __attribute__((packed)) xm_header {
   int8_t id_text[17];
   int8_t module_name[20];
@@ -139,3 +143,7 @@ static_assert((offsetof (struct xm_pattern_format, instrument)) == 1);
 static_assert((offsetof (struct xm_pattern_format, volume_column_byte)) == 2);
 static_assert((offsetof (struct xm_pattern_format, effect_type)) == 3);
 static_assert((offsetof (struct xm_pattern_format, effect_parameter)) == 4);
+
+#ifdef __cplusplus
+}
+#endif