[Q] two questions...

Hello. I'm developing a new MCP on M2L-PCI64B NIC. And I'm facing 
two problems right now. 

1. lanai-gcc is suspected to have a bug.
I spent lots of time to find where my bug lives and finally arrived here.
A pointer operation used in my MCP shows very strange result. To simplfy
my question, I list some parts of my code below. 

int gap;
mem_info_t mem_table[MAX];
mem_info_t *mem_ptr;

mem_ptr = &mem_table[index];
gap = mem_ptr-&mem_table[0];                    // (a)
gap = gap / 16;                                 // (b)

After line (a) is executed, the variable 'gap' shows 17. But after 
line (b) is executed the variable 'gap' shows 4 (not 1).    ;-)
By shifting 'gap' 4 bits instead of dividing by 16, (gap = gap >> 4), I can 
continue to work(fortunately the divisor is in the power of 2.). 
I'm using lanai-gcc version 2.95.2..1.4. In fact I don't think the lanai-gcc 
has a bug, but I can not understatnd this result. If my word is discourteous 
I apologize to Myricom team.
 
2. loopback packet is not received.
I expect that a packet sent from node A to itself is received to 
verify that a switch is still alive. I filled up all the bytes in the
routing header with 0x80 and set SA to 7. (I'm using 8 bytes routing
header in my MCP.) But no packet is received. I have no problem for 
communication among different nodes. A packet sent from node A is received
by node B. (node A should not be the same node as node B.) But a loopback
packet is not received. How can I solve this problem? 

Any comments and suggestions will be appreciated.
Thanks in advance...




------------Korea Advanced Institute of Science and Technology-------------
Moon-Sang Lee	    [email protected]
CS dept. KAIST      +82-42-869-5552@calab  
Western Dorm. 6118  +82-42-879-6617@dormitory
Homepage URL        http://camars.kaist.ac.kr/~mslee
---------------------Computer Architecture Laboratory----------------------