update J3_GetMachineCode()

include/jfont.h

@@ -81,6 +81,7 @@ void INT8_J3();
 void INT60_J3_Setup();
 uint8_t GetKanjiAttr();
 uint16_t GetGaijiSeg();
+uint16_t J3_GetMachineCode();
 void J3_SetBiosArea(uint16_t mode);
 
 enum DOSV_VTEXT_MODE {

src/ints/bios_keyboard.cpp

@@ -1407,8 +1407,8 @@ Bitu INT16_Handler(void) {
             if(reg_ax == size / 2) {
                 reg_ax = 0xffff;
             }
-            // J-3100 machine code(dummy)
-            reg_bx = 0x6a74;
+            // J-3100 machine code
+            reg_bx = J3_GetMachineCode();
         }
         break;
     default:

src/ints/int10_modes.cpp

@@ -39,7 +39,6 @@
 #define GFX_REGS 0x09
 #define ATT_REGS 0x15
 
-uint16_t J3_GetMachineCode();
 void J3_GetPalette(uint8_t no, uint8_t &r, uint8_t &g, uint8_t &b);
 extern bool window_was_maximized;
 extern bool enable_vga_8bit_dac;