On 25/05/2015 06:33, Ralf Quint wrote:
>> DIR: When using DIR/P, DIR seems to think that the screen is 1-row high,
>> and asks for a keypress for every line (the screen is CGA-based, 25
rows).
> That must be some issue with your PC, works fine for me and should not
> be related to 8086 code or not at all...
Hi, I had a few minutes of time to look into this. And what I was
half-guessing two days ago seems correct: my PC is fine, that's FreeCOM
who's buggy.
Here is an extract of what makes the DIR command wait after a page of
text (extracted from SVN's trunk and slightly reformatted for better
mail readability):
/* increment our line if paginating, display message at end of screen */
static int incline(void) {
if (!optP) return E_None;
if (++line >= MAX_Y) {
line = 0;
return pause();
}
return 0;
}
Now the obvious question of course is "what is MAX_Y?". And one grep
later, I've got the answer:
$ grep 'MAX_Y' -R *
cmd/dir.c: if (++line >= MAX_Y)
include/misc.h:#define MAX_Y (*(unsigned char far*)MK_FP(0x40, 0x84))
include/misc.h:#define SCREEN_ROWS (MAX_Y + 1)
(...)
This is exactly what I was implying in my previous message - FreeCOM
doesn't care about CGA, and assumes that the screen's height will always
be available under 0040:0084, which is true only for EGA+.
Mateusz
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