Improve dec_to_binary function.

mentos/inc/io/debug.h

@@ -60,7 +60,7 @@ const char *to_human_size(unsigned long bytes);
 /// @brief Transforms the given value to a binary string.
 /// @param value The decimal value.
 /// @return String representing the binary value.
-const char *dec_to_binary(unsigned long value);
+const char *dec_to_binary(unsigned long value, unsigned length);
 
 /// Prints a KERN_DEFAULT.
 #define pr_default(...) dbg_printf(__FILENAME__, __func__, __LINE__, __DEBUG_HEADER__, KERN_DEFAULT __VA_ARGS__)

mentos/src/io/debug.c

@@ -12,6 +12,7 @@
 #include "string.h"
 #include "stdio.h"
 #include "io/video.h"
+#include "math.h"
 
 /// Serial port for QEMU.
 #define SERIAL_COM1 (0x03F8)
@@ -185,10 +186,10 @@ const char *to_human_size(unsigned long bytes)
     return output;
 }
 
-const char *dec_to_binary(unsigned long value)
+const char *dec_to_binary(unsigned long value, unsigned length)
 {
     static char buffer[33];
-    for (int i = 0; i < 32; ++i)
-        buffer[i] = bit_check(value, 31 - i) ? '1' : '0';
+    for (int i = 0, j = 32 - min(max(0, length), 32); j < 32; ++i, ++j)
+        buffer[i] = bit_check(value, 31 - j) ? '1' : '0';
     return buffer;
 }