Hello,
i'm here again, i can confirm that the following code do not work well in my
environment.
PT_WAIT_UNTIL(&s->psockpt, data_acked(s) & send_data(s) );
but looking at the assembly code, as suggested by Till, we can see that both
expressions are evalueted before the jump, so it's not clear why it doesn't work
217: PT_WAIT_UNTIL(&s->psockpt, data_acked(s) & send_data(s) );
C:0x4B20 900002 MOV DPTR,#0x0002
C:0x4B23 E4 CLR A
C:0x4B24 75F0D9 MOV B(0xF0),#0xD9
C:0x4B27 122DAA LCALL C?ISTOPTR(C:2DAA)
C:0x4B2A 90D635 MOV DPTR,#psock_send?BYTE(0xD635)
C:0x4B2D 122DE3 LCALL C?PLDXDATA(C:2DE3)
C:0x4B30 12543C LCALL send_data(C:543C)
C:0x4B33 AC07 MOV R4,0x07
C:0x4B35 90D635 MOV DPTR,#psock_send?BYTE(0xD635)
C:0x4B38 122DE3 LCALL C?PLDXDATA(C:2DE3)
C:0x4B3B 12539E LCALL data_acked(C:539E)
C:0x4B3E EF MOV A,R7
C:0x4B3F 5C ANL A,R4
C:0x4B40 70D7 JNZ C:4B19
C:0x4B42 FF MOV R7,A
Anyway, by putting the two functions in one and having them explicitally
evalueted, and returning the combined result, it works fine.
Simone
----- Original Message -----
From: "Olaf Hartmann" <[EMAIL PROTECTED]>
To: <uip-users@sics.se>
Sent: Monday, March 05, 2007 11:04 AM
Subject: Re: [uip-users] Webserver problem
> Quoting Simone <[EMAIL PROTECTED]>:
>
>> Thanks a lot Peter!!
>> The buffer size seems to be one of the problems!! But the first one
>> i've figured out is this one: the & operator used in the psock.c
>> don't work as written in the comments below! There are at least a
>> couple of points in the code which are affected by this, maybe it's
>> due to the compiler and/or compiler optimizations i've used (it's the
>> keil c51).
>>
>> THE ORIGINAL CODE:
>>
>> /*
>> * The condition for this PT_WAIT_UNTIL is a little tricky: the
>> * protothread will wait here until all data has been acknowledged
>> * (data_acked() returns true) and until all data has been sent
>> * (send_data() returns true). The two functions data_acked() and
>> * send_data() must be called in succession to ensure that all
>> * data is sent. Therefore the & operator is used instead of the
>> * && operator, which would cause only the data_acked() function
>> * to be called when it returns false.
>> */
>>
>> PT_WAIT_UNTIL(&s->psockpt, data_acked(s) & send_data(s));
>>
>>
>> It seems that with my setup the evaluation of the expression
>> data_acked(s) & send_data(s) depends on the order of the operands and
>> it do not work in any case, so i've adjusted the code in this way,
>> using a temp variable to store the results and have both function
>> evaluated:
>>
>> THE CODE MODIFIED BY ME
>>
>> temp = 1;
>> temp &= data_acked(s);
>> temp &= send_data(s);
>> PT_WAIT_UNTIL(&s->psockpt, temp );
>
> Uhm. This patch is no good. =)
>
> The macro PT_WAIT_UNTIL implements a blocking wait for protothreads and
> gets translated to:
> temp = 1;
> temp &= data_acked(s);
> temp &= send_data(s);
> do {
> LC_SET((&s->psockpt)->lc);
> if(!(temp)) {
> return PT_WAITING;
> }
> } while(0)
> where LC_SET basically is a label that will be jumped to from the
> beginning of the function. So temp will not be evaluated every time as
> it should. If your variable temp isn't static or global it's contents
> is even random...
>
> But i agree that this data_acked() & send_data() code is very ugly and
> even seems to fail for you. I suggest that data_acked() and send_data()
> should be put into one function, which makes to code much more readable.
>
> btw: additionally psock_generator_send() has the problem, that it
> cannot retransmit packets, since the PT_WAIT_UNTIL() macro waits for an
> ack, but the retransmit is done in a loop around PT_WAIT_UNTIL.
>
> Greets
> Olaf
>
