 Sierra superVGAs:

SC15064  Falcon/64

3C4h index  7h
bit 5-7  (R) Chip id. 4: 15064

3C4h index 11h
bit   5  Clear to enable extensions
    6-7  Set to 0 to enable access >1Mb, 3 to disable banking?
Note: When unlocking read this register, write it back twice and write bit 5
      back as 0.

3C4h index 13h (R/W):
bit 0-7  Linear Frame Buffer Address in units of 1Mb.

3C4h index 14h (R/W):
bit 4-5  CRTC Offset bits 8-9. Bits 0-7 are in 3d4h index 13h

3C4h index 15h (R/W):
bit 0-7  Read Bank in units of 32Kbytes

3CDh (R/W):
bit 0-7  Write Bank in units of 32Kbytes

3CEh index 05h (R/W):
bit   7  Set to enable the Linear Frame Buffer
Note: Bits 0-6 are standard VGA.

3CEh index 0Ch (R/W):
bit 0-1  Set to 3 to enable 16bits/pixel?

3d4h index 1Eh (R/W):
bit 0-3  Display Start Address bits 16-19. Bits 0-15 are in 3d4h index 0Ch,0Dh

Video modes:

 58h G   800  600   16color
 59h G  1600 1200   16color
 5Ah G  1280 1024   16color
 5Bh G  1280 1024  256color
 5Ch G   800  600  256color
 5Dh G  1024  768   16color
 5Eh G  1024  768  256color
 5Fh G   640  480  256color
 60h G  1600 1280  256color
 69h G   640  480  16Mcolor
 6Eh G   640  480  32Kcolor
 6Fh G   800  600  32Kcolor
 70h G   800  600  16Mcolor
 71h G  1024  768  32Kcolor
 73h G  1024  768  16Mcolor
 75h G  1280 1024  32Kcolor































