assembly code to test for assign (2.0+)

jotd · 27 December 2017, 21:07

I have this code to test for an assign. Ex: pass a pointer on "T:" in D0 and it returns 0 if not found

Code:

    move.l    _DosBase,A6
   move.l	D0,D5
   move.l    #LDF_READ|LDF_WRITE|LDF_ALL,D1
    JSRLIB    LockDosList
    move.l    D0,D6        ; head of dos list

    ; search in the list
    
    move.l    D5,D2
    move.l    #LDF_READ|LDF_WRITE,D3    ; flags
    move.l    D6,D1
    JSRLIB    FindDosEntry

    move.l    D0,D4            ; return

    ; unlock dos list

    move.l    #LDF_READ|LDF_WRITE,D1    ; flags
    JSRLIB    UnLockDosList

    move.l    D4,D0            ; NULL: not found

The issue with that code (took me a while to narrow it down) is that using it randomly locks my application on system calls like Read or Lock...

Someone knows why? I'd like to keep that code, but if I have to get rid of it and replace by a "Lock" I'll do it (since my app switches the requesters off, I suppose it won't be an issue)

Edit: replacing the flags by just

Code:

move.l    #LDF_READ,D1

fixes the lock but not sure if the test works in that case

ross · 27 December 2017, 22:38

Hi jotd, have You tried

move.l #LDF_READ|LDF_ALL,D1

?

From Autodocs there is a possible deadlock using LDF_WRITE without
AttemptLockDosList() before.

jotd · 27 December 2017, 23:16

tried that and it didn't lock, but didn't find the assign either. Anyway, used a good old "doslib.Lock" with requesters off, and it does exactly the same thing (I don't need assign, I need to see if the T: directory exists). Moreover, my code needs to be 1.3 compatible, so the Lock solution works. thanks

27 December 2017, 21:07	#1
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,160	assembly code to test for assign (2.0+) I have this code to test for an assign. Ex: pass a pointer on "T:" in D0 and it returns 0 if not found Code: move.l _DosBase,A6 move.l D0,D5 move.l #LDF_READ\|LDF_WRITE\|LDF_ALL,D1 JSRLIB LockDosList move.l D0,D6 ; head of dos list ; search in the list move.l D5,D2 move.l #LDF_READ\|LDF_WRITE,D3 ; flags move.l D6,D1 JSRLIB FindDosEntry move.l D0,D4 ; return ; unlock dos list move.l #LDF_READ\|LDF_WRITE,D1 ; flags JSRLIB UnLockDosList move.l D4,D0 ; NULL: not found The issue with that code (took me a while to narrow it down) is that using it randomly locks my application on system calls like Read or Lock... Someone knows why? I'd like to keep that code, but if I have to get rid of it and replace by a "Lock" I'll do it (since my app switches the requesters off, I suppose it won't be an issue) Edit: replacing the flags by just Code: move.l #LDF_READ,D1 fixes the lock but not sure if the test works in that case Last edited by jotd; 27 December 2017 at 21:17.

27 December 2017, 22:38	#2
ross Defendit numerus Join Date: Mar 2017 Location: Crossing the Rubicon Age: 53 Posts: 4,468	Hi jotd, have You tried move.l #LDF_READ\|LDF_ALL,D1 ? From Autodocs there is a possible deadlock using LDF_WRITE without AttemptLockDosList() before.

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27 December 2017, 23:16	#3
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,160	tried that and it didn't lock, but didn't find the assign either. Anyway, used a good old "doslib.Lock" with requesters off, and it does exactly the same thing (I don't need assign, I need to see if the T: directory exists). Moreover, my code needs to be 1.3 compatible, so the Lock solution works. thanks

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