Date: Sat, 23 Dec 1995 23:43:35 -0500 (EST) From: "Jonathan M. Bresler" <jmb@freebsd.org> To: Torbjorn Granlund <tege@matematik.su.se> Cc: michael butler <imb@scgt.oz.au>, Torbjorn Granlund <tege@matematik.su.se>, freebsd-hackers@freebsd.org Subject: Re: Pentium bcopy 486DX-66 results Message-ID: <Pine.BSF.3.91.951223233447.23830A-100000@Aspen.Woc.Atinc.COM> In-Reply-To: <199512240224.DAA26871@insanus.matematik.su.se>
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On Sun, 24 Dec 1995, Torbjorn Granlund wrote:
>
> I don't have any 486 systems, so I cannot tell for sure. Here is a simple
> test program that you can use for timing tests:
here are results using 2.1.0-RELEASE, a 486dx-66 with an asus sp3g
motherboard and write-back cache discipline.
Aspen:[45] ./a.out
copy 8259
memcpy 8582
the results vary with the number of times in succession that i
run the program ;)
Once Twice Thrice 4th 5th 6th 7th
copy 8259 6730 6709 6708 6706 6736 6695
memcpy 8582 7363 7605 7491 6667 6863 7819
i had to change the comment sytle on several lines to satisfy gas
"GNU assembler version 1.92.3, FreeBSD $Revision: 1.4 $"
the original produced:
copy.s.orig: Assembler messages:
copy.s.orig:13: Warning: Missing operand value assumed absolute 0.
copy.s.orig:13: Error: Relocation error. Absolute 0 assumed.
copy.s.orig:13: Error: Ignoring junk 'zero' after expression
copy.s.orig:13: Error: Unimplemented segment type 0 in parse_operand
copy.s.orig:17: Warning: Missing operand value assumed absolute 0.
copy.s.orig:17: Error: Relocation error. Absolute 0 assumed.
copy.s.orig:17: Error: Bad Absolute Expression, absolute 0 assumed.
copy.s.orig:17: Error: Rest of line ignored. First ignored character is `0'.
copy.s.orig:19: Error: Rest of line ignored. First ignored character is `*'.
copy.s.orig:20: Error: no such opcode prefix ('nop')
copy.s.orig:24: Warning: Missing operand value assumed absolute 0.
copy.s.orig:24: Error: Relocation error. Absolute 0 assumed.
copy.s.orig:24: Error: Ignoring junk 'words pairwise*/' after expression
copy.s.orig:24: Error: Unimplemented segment type 131080 in parse_operand
here is the diff -c2 (just changed '/*' to '#' on lines 13, 17, 24)
*** copy.s.orig Sat Dec 23 23:25:25 1995
--- copy.s Sat Dec 23 23:33:59 1995
***************
*** 11,26 ****
shrl $3,%ecx /* count for unrolled loop */
! jz Lend /* if zero, skip unrolled loop */
movl (%edi),%eax /* Fetch destination cache line */
! .align 2,0x90 /* supply 0x90 for broken assemblers */
! Loop: movl 28(%edi),%eax /* allocate cache line for destination
! */
! nop /* we want these two insn to pair! */
movl (%esi),%eax /* read words pairwise */
movl 4(%esi),%edx
! movl %eax,(%edi) /* store words pairwise */
movl %edx,4(%edi)
--- 11,25 ----
shrl $3,%ecx /* count for unrolled loop */
! jz Lend # if zero, skip unrolled loop */
movl (%edi),%eax /* Fetch destination cache line */
! .align 2,0x90 # supply 0x90 for broken assemblers */
! Loop: movl 28(%edi),%eax /* allocate cache line for destination */
! nop # we want these two insn to pair! */
movl (%esi),%eax /* read words pairwise */
movl 4(%esi),%edx
! movl %eax,(%edi) # store words pairwise */
movl %edx,4(%edi)
Jonathan M. Bresler FreeBSD Postmaster jmb@FreeBSD.ORG
play go. ride bike. hack FreeBSD.--ah the good life
i am moving to a new job. PLEASE USE: jmb@FreeBSD.ORG
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