First post, by videogamer555
In CGA 320x200 4-color modes (video modes 4 and 5), what exactly are the starting memory addresses for the 2 fields? I know it is divided into 2 fields of alternating lines, rather than one continuous picture like in VGA mode. I know that the first field (lines 0, 2, 4, 6, etc) start at address 0xB8000, and I assumed the second field (lines 1, 3, 5, 7, etc) started IMMEDIATELY after this. However, I'm not so sure about this assumption, after I wrote a program in assembly language that was based on that assumption, and second field doesn't line up correctly with the first field.The first field is correctly aligned with the screen, so I am 100% certain that the first field's starting address is 0xB8000. However has assumed that the second field started at address 0xB9F40 (exactly 8000 bytes after the start of the first field, which is the number of bytes in the first field, such that the starting address of the second field occurred immediately after the end of the first field). If it does not in fact start at 0xB9F40, then where does the second field start?