diff --git a/src/include/libk/string.h b/src/include/libk/string.h
index 2b9ad9e..6b205ab 100644
--- a/src/include/libk/string.h
+++ b/src/include/libk/string.h
@@ -5,5 +5,6 @@
 
 extern void memset(void *__dest, u8 __src, usize len);
 extern void memcpy(void *__dest, void *__src, usize len);
+extern usize strlen(void *__dest);
 
 #endif
diff --git a/src/kernel/main.c b/src/kernel/main.c
index 50f2fbe..9eda2e9 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -40,7 +40,6 @@ void kmain(void *mb2_bootinfo)
 
     framebuffer fb;
     get_frame_buffer_with_bootinfo(&fb, &bootinfo);
-    KERNEL_TODO();
     tty *tty0 = tty_new(tty_type_raw_framebuffer, tty_mode_text);
     tty_set_framebuffer(tty0, &fb);
 
@@ -66,9 +65,9 @@ void get_frame_buffer_with_bootinfo(framebuffer *fb, bootinfo_t *bootinfo)
     fb->width = fbinfo->framebuffer_width;
     fb->height = fbinfo->framebuffer_height;
     fb->pixsize = fbinfo->framebuffer_bpp / 8;
-    memm_map_pageframes_to( // TODO 总共需要映射8MB空间，但是它只映射了2MB
+    fb->pixtype = rgb;
+    memm_map_pageframes_to(
         (u64)fb->pointer, (u64)fb->pointer,
         fb->width * fb->height * fb->pixsize,
         false, true);
-    KERNEL_TODO();
 }
diff --git a/src/kernel/tty/font.c b/src/kernel/tty/font.c
index c52e251..28bb72b 100644
--- a/src/kernel/tty/font.c
+++ b/src/kernel/tty/font.c
@@ -933,14 +933,14 @@ u64 font[256][64] = {
         // M
         0b00000000,
         0b00000000,
-        0b10000001, ///
-        0b11000011,
-        0b11000011,
-        0b10100101,
-        0b10101001,
-        0b10011001,
-        0b10011001,
-        0b10000001,
+        0b00100010, ///
+        0b00100010,
+        0b00100110,
+        0b01010101,
+        0b01001001,
+        0b01001001,
+        0b01001001,
+        0b01000001,
         0b10000001,
         0b10000001, //
         0b00000000,
diff --git a/src/kernel/tty/tty.c b/src/kernel/tty/tty.c
index 644c282..db3cc4f 100644
--- a/src/kernel/tty/tty.c
+++ b/src/kernel/tty/tty.c
@@ -2,6 +2,7 @@
 
 #include <kernel/kernel.h>
 
+#include <libk/string.h>
 #include <libk/string.h>
 
 tty_controller_t tty_ctrler;
@@ -125,7 +126,7 @@ inline static void newline(tty *ttyx)
     }
 }
 
-void tty_text_print(tty *ttyx, char *restrict string, u32 color, u32 bgcolor)
+void tty_text_print(tty *ttyx, char *string, u32 color, u32 bgcolor)
 {
     if (ttyx->mode != tty_mode_text)
         return;
@@ -142,7 +143,8 @@ void tty_text_print(tty *ttyx, char *restrict string, u32 color, u32 bgcolor)
         }
     }
     simple_lock_lock(ttyx->text.lock);
-    while (*string != '\0')
+    usize len = strlen(string);
+    for (char *str = string; string - str < len; string++)
     {
         char c = *string;
         if (c == '\n')
@@ -200,7 +202,6 @@ void tty_text_print(tty *ttyx, char *restrict string, u32 color, u32 bgcolor)
         }
         putchar(ttyx, c, color, bgcolor);
         ttyx->text.column++;
-        ++string;
     }
     if (ttyx->text.column == ttyx->text.width)
         newline(ttyx);
diff --git a/src/libk/Makefile b/src/libk/Makefile
index 3bbd251..9a200e3 100644
--- a/src/libk/Makefile
+++ b/src/libk/Makefile
@@ -38,7 +38,7 @@ endif
 
 ASMFLAGS := ${ASMFLAGS}
 
-S_SRCS = memset.s memcpy.s
+S_SRCS = memset.s memcpy.s strlen.s
 S_OBJS = ${S_SRCS:.s=.s.o}
 
 ################################
diff --git a/src/libk/string/arch/x86_64/strlen.s b/src/libk/string/arch/x86_64/strlen.s
new file mode 100644
index 0000000..28ff63f
--- /dev/null
+++ b/src/libk/string/arch/x86_64/strlen.s
@@ -0,0 +1,19 @@
+    section .text
+
+    global strlen
+; usize strlen(char *)
+strlen:
+    push rcx
+    
+    cld
+    mov al, 0
+    xor rcx, rcx
+    dec rcx
+    repne scasb
+
+    not rcx
+    dec rcx
+
+    mov rax, rcx
+    pop rcx
+    ret