For shits and giggles, I replaced the lvx instruction in
the Altivec check with '.long 0x00000000', which is guaranteed
to be an illegal instruction on all powerpc processors. And
then I ran gdb on one of the example programs:
-----
wendolyne:~/liboil/liboil/examples$ libtool gdb -args ./oil-inspect copy_u8
*** Warning: inferring the mode of operation is deprecated.
*** Future versions of Libtool will require --mode=MODE be specified.
GNU gdb 6.3.90_20051119-debian
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "powerpc-linux-gnu"...Using host libthread_db
library "/lib/tls/libthread_db.so.1".
(gdb) r
Starting program: /home/ds/liboil/liboil/examples/.libs/lt-oil-inspect copy_u8
Program received signal SIGILL, Illegal instruction.
0x0ff9dce8 in test_altivec (ignored=0x0) at liboilcpu.c:288
288 asm volatile (
(gdb) c
Continuing.
OIL: ERROR liboiltest.c 403: oil_test_check_impl(): function
conv_f32_s16_bitstuff in class conv_f32_s16 failed check (43.6562 > 0.1) ||
(outside=0)
copy_u8 (uint8_t *dest, uint8_t *src, int n)
all implementations:
copy_u8_motovec
sum abs difference: 0 (n=0)
disabled
copy_u8_altivec2
sum abs difference: 0 (n=0)
disabled
copy_u8_altivec
sum abs difference: 0 (n=0)
disabled
copy_u8_llints
profile: 5.88889 ticks (std.dev. 1.13116)
sum abs difference: 0 (n=100)
currently chosen
copy_u8_ints
profile: 6.88889 ticks (std.dev. 1.13116)
sum abs difference: 0 (n=100)
copy_u8_llints_duff
profile: 7.55556 ticks (std.dev. 1.14033)
sum abs difference: 0 (n=100)
copy_u8_libc
profile: 9.1 ticks (std.dev. 1.1701)
sum abs difference: 0 (n=100)
copy_u8_ref
flags: REF
profile: 14.4 ticks (std.dev. 1.12437)
copy_u8_ptr
profile: 21 ticks (std.dev. 1.125)
sum abs difference: 0 (n=100)
Program exited normally.
(gdb)
-----
Note that the altivec implementations are listed as 'disabled',
because the Altivec check failed.
After reinstating the lvx instruction in the test, I added the same
illegal instruction to one of the copy_u8 implementations,
copy_u8_altivec:
-----
wendolyne:~/liboil/liboil/examples$ ./oil-inspect copy_u8
OIL: ERROR liboiltest.c 403: oil_test_check_impl(): function
conv_f32_s16_bitstuff in class conv_f32_s16 failed check (44.6484 > 0.1) ||
(outside=0)
OIL: ERROR liboiltest.c 359: oil_test_check_impl(): illegal instruction in
copy_u8_altivec
copy_u8 (uint8_t *dest, uint8_t *src, int n)
all implementations:
copy_u8_altivec
sum abs difference: 0 (n=0)
copy_u8_llints
profile: 5.88889 ticks (std.dev. 1.13116)
sum abs difference: 0 (n=100)
currently chosen
copy_u8_motovec
profile: 6.22222 ticks (std.dev. 1.13575)
sum abs difference: 0 (n=100)
copy_u8_ints
profile: 7 ticks (std.dev. 1.125)
sum abs difference: 0 (n=100)
copy_u8_llints_duff
profile: 7.44444 ticks (std.dev. 1.14033)
sum abs difference: 0 (n=100)
copy_u8_libc
profile: 8.8 ticks (std.dev. 1.13093)
sum abs difference: 0 (n=100)
copy_u8_altivec2
profile: 10 ticks (std.dev. 1.125)
sum abs difference: 0 (n=100)
copy_u8_ref
flags: REF
profile: 14.7 ticks (std.dev. 1.12272)
copy_u8_ptr
profile: 20.7778 ticks (std.dev. 1.13575)
sum abs difference: 0 (n=100)
wendolyne:~/liboil/liboil/examples$
-----
Notice that liboil caught the illegal instruction in copy_u8_altivec
and disabled it automatically. It also noticed a problem in
conv_f32_s16_bitstuff, which I should probably fix. Those lines are
actually just warnings, since the performance of liboil is unchanged,
but I prefer the word "ERROR" because it causes people to report it
as a bug, which means it's more likely to get fixed.
By the way, I also have a G3 Mac right next to me that runs liboil
fine. I would have run the tests on that, but its gdb is broken.
dave...
--
David Schleef
Big Kitten LLC (http://www.bigkitten.com/) -- data acquisition on Linux
--
To UNSUBSCRIBE, email to [EMAIL PROTECTED]
with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
