Subject: Unaligned access in C library
To: NetBSD/Alpha <>
From: B. James Phillippe <>
List: port-alpha
Date: 02/16/2002 18:17:20

I am running 1.5.2 on a DEC Alpha, and have bumped into what I believe is
an unaligned access in the C library.  At least, I have an application
which blows up with "unaligned access" only when compiled with "-pg" for
profiling.  When I run the address through gbd, this is what I get:

% test/unix_util.TEST -r test/input.dump.1 tcp
pid 25891 (unix_util.TEST): unaligned access: va=0x1201aef14 pc=0x1200244d8 ra=0x120016e1c op=ldq
Segmentation fault
% gdb !:0                                                        (returned 139)
gdb test/unix_util.TEST
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This GDB was configured as "alpha--netbsd"...
(gdb) l *0x1200244d8
0x1200244d8 is in __setjmp14 (/usr/src/lib/libc/arch/alpha/gen/__setjmp14.S:67).
/usr/src/lib/libc/arch/alpha/gen/__setjmp14.S:62: No such file or directory.
(gdb) p *0x1201aef14
$1 = 0
(gdb) l *0x120016e1c
No source file for address 0x120016e1c.

If I pop open __setjmp14.c, line 67 contains CALL:

    /* see what's blocked */
    mov zero, a0            /* how (insignificant) */
    mov zero, a1            /* set (NULL) */
    lda a2, 648(s0)         /* point to mask in sc */

Which expands to:

 *  Function invocation
#define CALL(_name_)                        \
    .loc    1 __LINE__;                 \
    jsr ra,_name_;                  \
    ldgp    gp,0(ra)

Any advice?

# bryan at darkforest dot org
# Software Engineer