Initial XGA-2 implementation, (same as XGA-1 internally, but able to do 800x600 officially), selection is possible only on QT at the moment.

Refactored the ROP/MIX of the XGA accelerator.
Bus type variable added to make sure the device is an ISA-16 device or MCA in its dedicated register.

src/include/86box/vid_xga.h

@@ -64,6 +64,7 @@ typedef struct xga_t
     uint8_t pal_b, pal_b_prefetch;
     uint8_t sprite_data[1024];
     uint8_t scrollcache;
+    uint8_t direct_color;
     uint8_t *vram, *changedvram;
 
     int16_t hwc_pos_x;
@@ -92,6 +93,7 @@ typedef struct xga_t
     int op_mode_reset, linear_endian_reverse;
     int sprite_pos, sprite_pos_prefetch, cursor_data_on;
     int pal_test;
+    int type, bus;
 
     uint32_t linear_base, linear_size, banked_mask;
     uint32_t base_addr_1mb;

src/include/86box/vid_xga_device.h

@@ -0,0 +1,22 @@
+/*
+ * 86Box	A hypervisor and IBM PC system emulator that specializes in
+ *		running old operating systems and software designed for IBM
+ *		PC systems and compatibles from 1981 through fairly recent
+ *		system designs based on the PCI bus.
+ *
+ *		This file is part of the 86Box distribution.
+ *
+ *		IBM XGA emulation.
+ *
+ *
+ *
+ * Authors:	TheCollector1995.
+ *
+ *		Copyright 2022 TheCollector1995.
+ */
+
+#ifndef VIDEO_XGA_DEVICE_H
+# define VIDEO_XGA_DEVICE_H
+extern const device_t xga_device;
+extern const device_t xga_isa_device;
+#endif	/*VIDEO_XGA_DEVICE_H*/