Q43272: Printing ASCII Characters Greater Than 127 Fails in CGA Mode

Article: Q43272
Product(s): See article
Version(s): 5.00 5.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | s_quickc | mspl13_c
Last Modified: 17-MAY-1989

When a CGA graphics card is in any CGA graphics mode it will not
display ASCII characters greater than 127 when Microsoft C text-output
routines are used. Garbage characters will be displayed instead.

This is expected behavior. The default character-definition table for
CGA graphics cards contains only the first 128 ASCII characters. To
print ASCII characters 128 to 255, a separate character-definition
table must be set up and accessed through interrupt vector 1FH. The
MS-DOS utility GRAFTABL leaves such a table and hooks the interrupt
1FH vector to point to it.

For more information, see Richard Wilton's book "Programmer's Guide to
PC & PS/2 Video Systems," Page 269, which is available from Microsoft
Press.

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