Added basic implmementation of %x to vsprintf.

2 files changed, 25 insertions, 1 deletions

diff --git a/kernel/kmain.c b/kernel/kmain.c
index 52c41d1..a854c12 100644
--- a/kernel/kmain.c
+++ b/kernel/kmain.c
@@ -8,5 +8,5 @@ void kmain(void) {
   printf("Kernel booting...\n");
   printf("Kernel booted!\n");
 
-  printf("%s %s %s\n%s %s %s\n",  "first", "second", "third", "fourth", "fifth", "sixth");
+  printf("Number: %x\n", 0x80);
 }
diff --git a/kernel/vsprintf.c b/kernel/vsprintf.c
index dca2906..20489f4 100644
--- a/kernel/vsprintf.c
+++ b/kernel/vsprintf.c
@@ -8,7 +8,22 @@ enum TYPE {
   TYPE_STRING = 4
 };
 
+static void hex(char **str, int x) {
+  int n;
+  char *s = "0x";
+
+  while(*s)
+    *(*str)++ = *s++;
+
+  n = sizeof(x) << 1;
+  while(n--) {
+    *(*str)++ = ((unsigned int) x >> 28) + 0x30;
+    x = x << 4;
+  }
+}
+
 int vsprintf(char *str, char *fmt, va_list ap) {
+  int x;
   char *s;
   char *start = str;
   uint8_t type;
@@ -29,6 +44,11 @@ int vsprintf(char *str, char *fmt, va_list ap) {
             goto done;
           type = TYPE_STRING;
           break;
+        case 'x':
+          if(type)
+            goto done;
+          type = TYPE_HEX;
+          break;
         default:
           goto done;
           break;
@@ -44,6 +64,10 @@ done:
         while(*s)
           *str++ = *s++;
         break;
+      case TYPE_HEX:
+        x = va_arg(ap, int);
+        hex(&str, x);
+        break;
     }
   }