[Freedos-kernel] Tom's kernel changes vs. CVS
Hi,
I've put on some effort in merging Tom's changes into the current CVS
('stable').
Thanks to Eric for forwarding the patch. Committing them back into CVS
is mostly done now.
Many of the changes in Tom's kernel, when compared to 2035 plain, were
already there (or in a slightly different form), some are not.
I'm left with the small diff below of changes I do not understand.
Tom, can you explain?
1. config.c. Why use instead of =? Is there a corner case with equality?
2. initoem.c:
+ if (ramsize == peek(0, RAMSIZE))
if (ramsize * 64 == ebdaseg ramsize 640 peek(0, RAMSIZE) == ramsize)
the extra double check looks strange to me, why check twice?
Something strange with short-circuit boolean evaluation?
3. int21/ax=3301. The comment and the code are out of sync. By falling
through it reports the new state of break_ena in DL (not AL).
Moreover, RBIL tells us that Novell DOS 7 report the *old* state
(instead of the new state) in DL. What is the intended logic here?
Thanks,
Bart
--- ke2035/kernel/config.c 2004-05-25 01:02:46.0 -0400
+++ ke2035ctom/kernel/config.c 2007-05-14 12:43:46.0 -0400
@@ -753,8 +753,8 @@
if (timeout = 0) do
{
r.a.x = 0x0100; /* are there keys available ? */
init_call_intr(0x16, r);
-if ((unsigned)(GetBiosTime() - startTime) = timeout * 18u)
+if ((unsigned)(GetBiosTime() - startTime) timeout * 18u)
return 0x;
}
while (r.flags FLG_ZERO);
diff -urb ke2035/kernel/dsk.c ke2035ctom/kernel/dsk.c
+++ ke2035ctom/kernel/initoem.c 2007-05-14 12:43:46.0 -0400
@@ -58,7 +59,8 @@
unsigned ebdaseg = peek(0, EBDASEG);
unsigned ramsize = ram_top;
+ if (ramsize == peek(0, RAMSIZE))
if (ramsize * 64 == ebdaseg ramsize 640 peek(0, RAMSIZE) == ramsize)
{
unsigned ebdasz = peekb(ebdaseg, 0);
diff -urb ke2035/kernel/inthndlr.c ke2035ctom/kernel/inthndlr.c
--- ke2035/kernel/inthndlr.c2004-05-30 20:31:06.0 -0400
+++ ke2035ctom/kernel/inthndlr.c2007-05-14 12:43:46.0 -0400
@@ -78,17 +78,17 @@
case 0x33:
switch (irp-AL)
{
+ /* Set Ctrl-C flag; returns al = break_ena */
+case 0x01:
+ break_ena = irp-DL 1;
+ /* fall through */
+
/* Get Ctrl-C flag */
case 0x00:
irp-DL = break_ena;
break;
- /* Set Ctrl-C flag */
-case 0x01:
- break_ena = irp-DL 1;
- break;
-
case 0x02: /* andrew schulman: get/set extended
control break */
{
UBYTE tmp = break_ena;
-
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Re: [Freedos-kernel] Tom's kernel changes vs. CVS
Hi Bart,
nice to see you're still alive :)
Tom, can you explain?
1. config.c. Why use instead of =? Is there a corner case with equality?
IMO = is correct (timeout 0 should exit immediately)
2. initoem.c:
+ if (ramsize == peek(0, RAMSIZE))
if (ramsize * 64 == ebdaseg ramsize 640 peek(0, RAMSIZE) == ramsize)
the extra double check looks strange to me, why check twice?
Something strange with short-circuit boolean evaluation?
looks strange, and I have no idea why exactly this is there.
But since I put it in after ke2035, I just assume I did that
intentionally. (this was changed on or before 11.07.2004)
I'd leave it under 'it doesn't hurt'
3. int21/ax=3301. The comment and the code are out of sync.
By falling
through it reports the new state of break_ena in DL (not AL).
right
besides that, the code should do the same in both cases (DL should be
00 or 01)
I don't mind much
Tom
Moreover, RBIL tells us that Novell DOS 7 report the *old* state
(instead of the new state) in DL. What is the intended logic here?
Thanks,
Bart
--- ke2035/kernel/config.c 2004-05-25 01:02:46.0 -0400
+++ ke2035ctom/kernel/config.c 2007-05-14 12:43:46.0 -0400
@@ -753,8 +753,8 @@
if (timeout = 0) do
{
r.a.x = 0x0100; /* are there keys available ? */
init_call_intr(0x16, r);
-if ((unsigned)(GetBiosTime() - startTime) = timeout * 18u)
+if ((unsigned)(GetBiosTime() - startTime) timeout * 18u)
return 0x;
}
while (r.flags FLG_ZERO);
diff -urb ke2035/kernel/dsk.c ke2035ctom/kernel/dsk.c
+++ ke2035ctom/kernel/initoem.c 2007-05-14 12:43:46.0 -0400
@@ -58,7 +59,8 @@
unsigned ebdaseg = peek(0, EBDASEG);
unsigned ramsize = ram_top;
+ if (ramsize == peek(0, RAMSIZE))
if (ramsize * 64 == ebdaseg ramsize 640 peek(0, RAMSIZE) ==
ramsize)
{
unsigned ebdasz = peekb(ebdaseg, 0);
diff -urb ke2035/kernel/inthndlr.c ke2035ctom/kernel/inthndlr.c
--- ke2035/kernel/inthndlr.c2004-05-30 20:31:06.0 -0400
+++ ke2035ctom/kernel/inthndlr.c2007-05-14 12:43:46.0 -0400
@@ -78,17 +78,17 @@
case 0x33:
switch (irp-AL)
{
+ /* Set Ctrl-C flag; returns al = break_ena */
+case 0x01:
+ break_ena = irp-DL 1;
+ /* fall through */
+
/* Get Ctrl-C flag */
case 0x00:
irp-DL = break_ena;
break;
- /* Set Ctrl-C flag */
-case 0x01:
- break_ena = irp-DL 1;
- break;
-
case 0x02: /* andrew schulman: get/set extended
control break */
{
UBYTE tmp = break_ena;
-
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Mit freundlichen Grüßen / Kind regards,
Tom Ehlert
+49-241-79886
-
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Re: [Freedos-kernel] Tom's kernel changes vs. CVS
Hi Bart, Tom, some extra comment for 2. initoem.c: + if (ramsize == peek(0, RAMSIZE)) if (ramsize * 64 == ebdaseg ramsize 640 peek(0, RAMSIZE) == ramsize) the extra double check looks strange to me, why check twice? Something strange with short-circuit boolean evaluation? ... I got the recommendation do not move EBDA unless it starts at the segment where low DOS RAM ends according to 40[13], as another location could mean that something else fiddled with the location / memory already. Of course that does not answer the question why ramsize == peek(0, RAMSIZE) is checked for twice. Eric PS: Bart, could you make a list which things you merged in from Tom's kernel and which you did not? I would like to compare it to my own list... Thanks :-). PPS: Did you also check in the changes from the kernel on my homepage? If so, I hope you grabbed some of the changelog and put it into the cvs logs. Good cvs logs are always very useful. If you did not check in my changes yet, remind me to do myself ;-). - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Freedos-kernel mailing list Freedos-kernel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-kernel
