Re: [parisc-linux] Back to evms-1.0.1 && unaligne access && gdb

[jsoe0708@tiscali.be]

>-- Original Message --
>Subject: Re: [parisc-linux] Back to evms-1.0.1 && unaligne access && gdb
>To: jsoe0708@tiscali.be
>From: "John David Anglin" <dave@hiauly1.hia.nrc.ca>
>Cc: parisc-linux@lists.parisc-linux.org
>Date: Thu, 29 Aug 2002 10:28:48 -0400 (EDT)
>
>
>> >Program received signal SIGINT, Interrupt.
>> >0x4020a0e4 in isa_null_partition_record (p=0x3fe0ff) at checks.c:65
>
>You can see from the value of p above that it is not properly aligned
>for a 4 byte access.  Put a break on isa_null_partition_record and
>
>cond n p==0x3fe0ff
>
>where n is the breakpoint number of the break at isa_null_partition_record.

As previously, I could not put a break at isa_null_partition_record (function
not define but with ^C I reach to stop recursively in this function and so
for example with p==0x26ece I got p.boot_ind=0 ; p.head=63 ; p.sector=224
; p.cyl=255; ...

p is of type partition define as follow:
struct partition {
    unsigned char boot_ind;     /* 0x80 - active */
    unsigned char head;     /* starting head */
    unsigned char sector;       /* starting sector */
    unsigned char cyl;      /* starting cylinder */
    unsigned char sys_ind;      /* What partition type */
    unsigned char end_head;     /* end head */
    unsigned char end_sector;   /* end sector */
    unsigned char end_cyl;      /* end cylinder */
    unsigned int start_sect;    /* starting sector counting from 0 */
    unsigned int nr_sects;      /* nr of sectors in partition */
};

So anyway there is a bug because I presume that the for loop is there to
scan the 4 int what it doen't do (?) and find another way to say an 'int'
is null ( hmm why not simply 
u_int8_t *uip = (u_int8_t *)p;
for (i=0 ; i<16 ; i++){
    if (*uip+i != 0x00) return FALSE;
}
return TRUE;

what do you think?


>Then, run the program and it should stop at isa_null_partition_record
>when the fault is about to occur.  You will then have to do a bt to
>determine why p is incorrectly aligned (last hex digit should be 0,
>4, 8 or c).

Many thanks,
    Joel