Int 10 Fn 1000  - Video - Set Single Palette Register (pcjr,tandy,ega,mcg  [V]

   AX = 1000h
   BL = palette register number (00h-0Fh)
      = attribute register number (undocumented) (see #0016)
   BH = color or attribute register value

Return: nothing

Notes: on MCGA, only BX = 0712h is supported
   under UltraVision, the palette locking status (see AX=CD01h)
     determines the outcome

See Also: AX=1002h,AX=1007h,AX=CD01h

(Table 0016)
Values for attribute register number:
 10h   attribute mode control register (should let BIOS control this)
 11h   overscan color register (see also AX=1001h)
 12h   color plane enable register (bits 3-0 enable corresponding
     text attribute bit)
 13h   horizontal PEL panning register
 14h   color select register