Re: [Freedos-devel] [Freedos-cvs] freecom/lib c16.mac, NONE, 1.1 app_get.c, 1.2, 1.3 beep_l.c, 1.2, 1.3 beep_n.c, 1.2, 1.3 cd_dir.c, 1.6, 1.7 cmdinput.c, 1.5, 1.6 critrchk.c, 1.2, 1.3 farread.c, 1.2, 1.3 fcompl2.c, 1.2, 1.3 fdattr.c, 1.2, 1.3 fdsattr.c, 1.3, 1.4 goxy.c, 1.2, 1.3 hdlrctxt.c, 1.1, 1.2 inputdos.c, 1.3, 1.4 keyprsd.c, 1.2, 1.3 mk_rddir.c, 1.4, 1.5 msg_dps.c, 1.3, 1.4 msg_prmp.c, 1.2, 1.3 mux_ae.c, 1.5, 1.6 prprompt.c, 1.3, 1.4 showcmds.c, 1.3, 1.4 timeget.c, 1.2, 1.3 timeset.c, 1.2, 1.3 truncate.c, 1.2, 1.3 vcgetch.c, 1.2, 1.3 vcgetstr.c, 1.2, 1.3

[Arkady V.Belousov]

Hi!

14-Июн-2006 19:01 [EMAIL PROTECTED] (Alain M.) wrote to
freedos-devel@lists.sourceforge.net:

>> AB> Now the the real reason for the mail. Arkady said that the int*()
>> AB> function do not pass on the flags correctly.
>>      They do not do this at all.
AM> Yes. it leaves it uninitialized!

     No, CF state _always_ initialized, but initialization value depends
from (internal) code of int*() function.

     And quick observation of intr() source code shows, that before calling
interrupt, CF is 1 before INT 0-25 and 0 before INT 26-FF (see cmp/jb and
cmp/ja below):

asm     cmp     al, 025h
asm     jb      NormalIntr
asm     cmp     al, 026h
asm     ja      NormalIntr
[...a lot of "asm mov"...]
asm     jmp     SetRegs
NormalIntr:
asm     mov     byte ptr Code+5, 0CAh
asm     mov     word ptr Code+6, 2
SetRegs:
[...a lot of "asm lds/push/mov"...]
        /* Call the interrupt routine */
        (* Vector)();

>> AB> Of course using asm{} is more efficient, but is not C++.
>>      This depends. First, yes - in OW asm{} forces saving all registers on
>> stack (even if in asm{} no registers used), but TC/BC is smarter in this
>> (they check, which registers mentioned in instructions).
AM> IMHO, for portability, there could be an asm function to do those
AM> things.

     (Inline) asm function does _not_ better for portability (unless there
is no C-like way to perform required task).

AM> It is just too bad that just one bit got left out of the
AM> Standard/Borland functions...

     ?

>>      Second, see how much workarounds you apply (store firstly to _CX and
>> _BX, then move to _DX and _AX) to avoid registers injuring. But with
>> pseudo-variables you can't guarantee non-injuring - only reviewing listing
>> may ensure, that with this compiler version your code compiled as expected.
>> Whereas with asm{} you get only what you wrote - no more, no less.
AM> I am used to BC31, which has asm{}, but unfortunately FreeDOS has to use
AM> the older versions  :(

     Yes, I forget, that there is no built-in inline asm support in TC. :(


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