[feat] 串口hex输出可选择是否补0

kernel/serial.cpp

@@ -32,15 +32,31 @@ void serial_write(String str) {
     }
 }
 
-void serial_write_hex(UINTN val) {
+void serial_write_hex(UINTN val, bool fill) {
     char buf[19];
-    buf[0] = '0'; buf[1] = 'x';
-    for (SSINT32 i = 17; i >= 2; i--) {
-        UINTN digit = val & 0xF;
-        buf[i] = digit < 10 ? '0' + digit : 'A' + digit - 10;
-        val >>= 4;
+    buf[0] = '0';
+    buf[1] = 'x';
+    SSINT32 pos = 2;
+    if (val == 0) {
+        buf[pos++] = '0';
+    } else {
+        char tmp[17];
+        SSINT32 len = 0;
+        while (val) {
+            UINTN digit = val & 0xF;
+            tmp[len++] = digit < 10 ? '0' + digit : 'A' + digit - 10;
+            val >>= 4;
+        }
+        if (fill) {
+            while (len < 16) {
+                buf[pos++] = '0';
+            }
+        }
+        for (SSINT32 i = len - 1; i >= 0; i--) {
+            buf[pos++] = tmp[i];
+        }
     }
-    buf[18] = '\0';
+    buf[pos] = '\0';
     serial_write(buf);
 }