17
votes
How to use all memory on an IBM PC with 8086
Assuming there is usable memory between 640K and 1024K (which would be rather unusual in an 8086 PC), I would recommend using DOS 5.0 or later and adding UMBs to the memory allocation strategy (there ...
- 118k
17
votes
Accepted
C64 char screen plot routine - not clear about reason for logical OR
C64 screen memory by default begins at $0400. The ORA #$04 ensures that you are treating location (0, 0) as address $0400, treating the location one to the right of that as $0401, etc.
It has the same ...
- 36k
16
votes
Accepted
What problem does LOADFIX solve?
In short, it prevents a code bug from triggering in some executables compressed by Microsoft EXEPACK.
Programs themselves are supposed to work at any address, but these executables are packed with ...
- 28.3k
11
votes
How to use all memory on an IBM PC with 8086
The short answer is, there is no usable RAM there so you can't use any. If you have an MDA video card, it has only 4096 bytes of video memory, and for 80x25 screen, it uses 4000 bytes already, so ...
- 28.3k
11
votes
Accepted
How to write Win16 program with only a single segment (combined code+data)?
I don’t think this is supposed to be possible at all.
One reason why is that Windows may decide to run your program in protected mode. Your program obviously needs to have one executable segment to ...
- 21.6k
4
votes
Why is the Amiga ROM at a high memory location, and RAM in low memory?
I'm not allowed to comment, so I'll add this here. The ROM overlay reset 'hack' was not limited to 68000's, and was well-established in the industry by the time the 68000 was introduced. (Intel 8080 ...
- 107
2
votes
Accepted
Details of ZS Scorpion port 0x1ffd
There was several unofficial modifications of Scorpion memory:
DejaVu #0A disk magazine: ZS Scorpion 1024 scheme. Here is a translation.
ZX Light #0C disk magazine: ZS Sсorрion 256 memory expansion ...
- 144
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