void vga_alpha_switch_to_font_plane() {
vga_write_GC(0x4,0x02); /* NTS: Read Map Select: This is very important if the caller wants to read from the font plane without reading back gibberish */
vga_write_GC(0x5,0x00);
vga_write_GC(0x6,0x0C);
vga_write_sequencer(0x2,0x04);
vga_write_sequencer(0x4,0x06);
}
void vga_alpha_switch_from_font_plane() {
vga_write_GC(0x4,0x00);
vga_write_GC(0x5,0x10);
vga_write_GC(0x6,0x0E);
vga_write_sequencer(0x2,0x03);
vga_write_sequencer(0x4,0x02);
}
/* EGA/VGA only */
void vga_set_memory_map(unsigned char c) {
unsigned char b;
if (vga_state.vga_flags & VGA_IS_VGA) {
b = vga_read_GC(6);
vga_write_GC(6,(b & 0xF3) | (c << 2));
update_state_vga_memory_map_select(c);
}
else if (vga_state.vga_flags & VGA_IS_EGA) {
/* guessing code because you can't readback regs on EGA */
b = int10_getmode();
/* INT 10H text modes: set odd/even, else, set alpha disable */
vga_write_GC(6,0x02 | (c << 2));
update_state_vga_memory_map_select(c);
}
}
