From: Dave Brolley <brolley@redhat.com>
To: Dave Brolley <brolley@redhat.com>
Cc: cgen@sources.redhat.com
Subject: Re: [patch][rfa] -opcode-slots: Handling of short insns
Date: Wed, 28 Jan 2004 19:34:00 -0000 [thread overview]
Message-ID: <40180ED9.7060104@redhat.com> (raw)
In-Reply-To: <40180031.9040108@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 3616 bytes --]
Attached the wrong file.....
Dave Brolley wrote:
> Hi,
>
> This patch fixes a problem I ran across while working on an internal
> port. Incorrect opcodes and masks were sometimes being generated for
> the short insns of variable length ISAs because of two problems in
> -opcode-slots:
>
> 1) The test of bit positions against the insn-length was off by one.
> Thjs could lead to incorrect opcode bits being generated.
>
> 2) While the 'compute' function correctly generated zeroes for the
> extra bits when computing 'opcode', it was also generating zeroes for
> these bits when computing 'opcode-mask', thus rendering these bits
> irrelevent. This could lead to the generation of numerous unreachable
> cases in the generated decoder switch.
>
> The patch corrects the comparison of bit position against the
> insn-length and also allows the caller of 'compute' to specify the
> default bit value which should be generated bits beyond the length of
> a short insn. This allows 0 to be specified when computing 'opcode'
> and 1 to be specified when computing opcode-mask. The patch also
> changes some of the logit calls to print values in hex which is more
> appropriate when examining bitmasks
>
> This patch corrects the problem encountered with my internal port. I
> know of no other port which is affected by this bug. I have tested it
> against frv and xstormy16 and verified no changes to the generated
> decoders.
>
> OK to commit?
>
> Dave
>
>------------------------------------------------------------------------
>
>2004-01-28 Dave Brolley <brolley@redhat.com>
>
> * decode.scm (-opcode-slots): For short insns, generate 'opcode' with
> zeroes in the extra bit positions and generate 'opcode-mask' with ones
> in the extra bit positions.
>
>
>
>------------------------------------------------------------------------
>
>cgen/ChangeLog:
>2004-01-26 Dave Brolley <brolley@redhat.com>
>
> * decode.scm (-opcode-slots): For short insns, generate 'opcode' with
> zeroes in the extra bit positions and generate 'opcode-mask' with ones
> in the extra bit positions.
>
>cgen/cpu/ChangeLog.RedHat:
>2004-01-26 Dave Brolley <brolley@redhat.com>
>
> * mep.opc (OPTION_MASK): Remove dangerous whitspace following a
> backslash intended as a line continuation.
>
>sid/main/dynamic/ChangeLog.RedHat:
>2004-01-26 Dave Brolley <brolley@redhat.com>
>
> * mepCfg.h (allocate_timer, configure_timer): New methods of MepBoardCfg.
> (set_opt_timer_channel_bitw): New method of MepBoardCfg.
> (timer_channel_bitw): New member of MepBoardCfg.
> * mepCfg.cxx (MepBoardCfg): Initialize timer_channel_bitw.
> (set_dmem_bank_num): Allow dmem_bank_num to be set to zero.
> (map_imem_dmem): Correct fmem_base_address for case of no dmem.
> Initialize dmem_base[0].
> (MepBoardCfg::write_config): Call configure_timer. Move setup of timer
> interrupt pins to configure_timer. Handle case where dmem_bank_num is
> zero.
> (add_timer): Move allocation, scheduling and connection of timer to
> allocate_timer and configure_timer.
> (allocate_timer, configure_timer): New methods of MepBoardCfg.
> (configure_dmac): Use timer_channel_bitw.
> (set_opt_timer_channel_bitw): New method of MepBoardCfg.
> * mainDynamic.cxx (usage): Document --timer-channel-bitw.
> (option_num): Add opt_timer_channel_bitw.
> (long_options): Add timer-channel-bitw.
> (main): Handle opt_timer_channel_bitw.
> * commonCfg.h (set_opt_timer_channel_bitw): New prototype.
>
>utils/mep/ChangeLog:
>2004-01-26 Dave Brolley <brolley@redhat.com>
>
> * mepcfgtool.c (generate_simulator_script): Generate
> --timer-channel-bitw
>
>
>
[-- Attachment #2: decode.patch.txt --]
[-- Type: text/plain, Size: 3255 bytes --]
Index: cgen/decode.scm
===================================================================
RCS file: /cvs/src/src/cgen/decode.scm,v
retrieving revision 1.9
diff -c -p -r1.9 decode.scm
*** cgen/decode.scm 21 Oct 2003 16:42:00 -0000 1.9
--- cgen/decode.scm 28 Jan 2004 18:15:11 -0000
***************
*** 1,5 ****
; Application independent decoder support.
! ; Copyright (C) 2000 Red Hat, Inc.
; This file is part of CGEN.
;
; This file provides utilities for building instruction set decoders.
--- 1,5 ----
; Application independent decoder support.
! ; Copyright (C) 2000, 2004 Red Hat, Inc.
; This file is part of CGEN.
;
; This file provides utilities for building instruction set decoders.
***************
*** 433,462 ****
(letrec ((opcode (insn-value insn))
(insn-len (insn-base-mask-length insn))
(decode-len (length bitnums))
! (compute (lambda (val insn-len decode-len bl)
;(display (list val insn-len decode-len bl)) (newline)
; Oh My God. This isn't tail recursive.
(if (null? bl)
0
! (+ (if (> (car bl) insn-len)
! 0
! (if (bit-set? val
! (if lsb0?
! (car bl)
! (- insn-len (car bl) 1)))
! (integer-expt 2 (- (length bl) 1))
! 0))
! (compute val insn-len decode-len (cdr bl)))))))
! (let* ((opcode (compute (insn-value insn) insn-len decode-len bitnums))
! (opcode-mask (compute (insn-base-mask insn) insn-len decode-len bitnums))
(indices (missing-bit-indices opcode-mask (- (integer-expt 2 decode-len) 1))))
(logit 3 "insn =" (obj:name insn)
! " insn-value=" (insn-value insn)
! " insn-base-mask=" (insn-base-mask insn)
" insn-len=" insn-len
" decode-len=" decode-len
! " opcode=" opcode
! " opcode-mask=" opcode-mask
" indices=" indices "\n")
(map (lambda (index) (+ opcode index)) indices)))
)
--- 433,462 ----
(letrec ((opcode (insn-value insn))
(insn-len (insn-base-mask-length insn))
(decode-len (length bitnums))
! (compute (lambda (val insn-len decode-len bl default)
;(display (list val insn-len decode-len bl)) (newline)
; Oh My God. This isn't tail recursive.
(if (null? bl)
0
! (+ (if (or (and (>= (car bl) insn-len) (= default 1))
! (and (< (car bl) insn-len)
! (bit-set? val
! (if lsb0?
! (car bl)
! (- insn-len (car bl) 1)))))
! (integer-expt 2 (- (length bl) 1))
! 0)
! (compute val insn-len decode-len (cdr bl) default))))))
! (let* ((opcode (compute (insn-value insn) insn-len decode-len bitnums 0))
! (opcode-mask (compute (insn-base-mask insn) insn-len decode-len bitnums 1))
(indices (missing-bit-indices opcode-mask (- (integer-expt 2 decode-len) 1))))
(logit 3 "insn =" (obj:name insn)
! " insn-value=" (number->hex (insn-value insn))
! " insn-base-mask=" (number->hex (insn-base-mask insn))
" insn-len=" insn-len
" decode-len=" decode-len
! " opcode=" (number->hex opcode)
! " opcode-mask=" (number->hex opcode-mask)
" indices=" indices "\n")
(map (lambda (index) (+ opcode index)) indices)))
)
next prev parent reply other threads:[~2004-01-28 19:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-28 18:32 Dave Brolley
2004-01-28 19:34 ` Dave Brolley [this message]
2004-01-28 22:52 ` Ben Elliston
2004-01-29 20:22 ` Dave Brolley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=40180ED9.7060104@redhat.com \
--to=brolley@redhat.com \
--cc=cgen@sources.redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).