Compatibility: VGA
Expects: AX    1009H
ES:BX address of 17-byte buffer to receive data
Returns: ES:BX buffer contains 16 palette regs + overscan reg
Info: This obtains the current rgbRGB values of all the VGA palette
registers and the overscan (border) register.  See INT 10H 1000H
and EGA I/O Ports for info on rgbRGB palette register settings.

ES:BX must point to a 17-byte buffer to receive the data.

Notes:   This is typically used by a program which wants to save the
palette in order to restore it later.  You may prefer to use
INT 10H 1cH for save/restore operations.

  Since the EGA BIOS does not support this fn, palette
manipulation by TSRs and task-switchers is difficult.  The
standard DOS device driver, EGA.SYS intercepts INT 10H and
emulates this function (it tracks the current palette as set
via BIOS calls, but cannot track direct I/O port manipulation).

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INT 10H 1009H: Read All Palette Registers