Where is the character map ?

The character maps are located on the video bios. Font functions are on INT 10h with AH = 11h and AL set to the subfunction number.

This link is a reference to all the video bios routines, note ~1909kB
www.versalogic.com/support/downloads/pdf/69030bg.pdf

You may also want to download ralf brown's interrupt list from here
www.cs.cmu.edu/~ralf/files.html

note character font cells are stored in msb -> lsb, here is a code snippet I wrote in the euphoria programming language that dementrates fow fonts are stored

Code:


    -- legacy bios -> get 8x8 doulbe-dot font pointer...

    dpmi[REG_AX] = #1130
    dpmi[REG_BX] = #0300                     -- get pointer to 1st 128 chars
    dpmi = dos_interrupt(#10,dpmi)
    pointer = dpmi[REG_ES] * 16
            + dpmi[REG_BP]
    bytes = peek({pointer,((1*8)*128)})      -- ((1 bbp * 8 lines) * 128)

    -- note: the value returned in cx will be the bytes per character for
             the active font (typicly 8x16), NOT the actual font requested.

    dpmi[REG_AX] = #1130                     -- get pointer to 2nd 128 chars
    dpmi[REG_BX] = #0400
    dpmi = dos_interrupt(#10,dpmi)
    pointer = dpmi[REG_ES] * 16
            + dpmi[REG_BP]
    bytes &=peek({ponter,((1*8)*128)})

    -- character bytes are stored in MSB format ( quite dumb ) to we need
    -- to transform each byte to LSB format....

    for i = 1 to length(bytes) by 1 do
        bits = int_to_bits(bytes[i],8)
        bits = reverse(bits) 
        bytes[i] = bits_to_int(bits)
    end for

    -- groups the bytes into characters so we can display the chars in eu's
    -- graphics modes with 'display_image()'

    chars = {}
    for i = 1 to length(bytes) by 8 do
        chars = append(chars,bytes[i..(7+i)])
    end for