This is the mail archive of the
cgen@sources.redhat.com
mailing list for the CGEN project.
[RFA:] Fix lsb? bug with insn fields beyond base insn size.
- From: Doug Evans <dje at transmeta dot com>
- To: Hans-Peter Nilsson <hans-peter dot nilsson at axis dot com>
- Cc: cgen at sources dot redhat dot com
- Date: Fri, 21 Jun 2002 13:54:10 -0700 (PDT)
- Subject: [RFA:] Fix lsb? bug with insn fields beyond base insn size.
- References: <200206190111.DAA19613@ignucius.axis.se>
Hans-Peter Nilsson writes:
> Ok to commit?
>
> 2002-06-19 Hans-Peter Nilsson <hp@axis.com>
>
> * types.scm (bitrange-overlap?): Handle lsb0?.
> * utils-gen.scm (-gen-extract-word): Ditto.
>
> Index: utils-gen.scm
> ===================================================================
> RCS file: /cvs/src/src/cgen/utils-gen.scm,v
> retrieving revision 1.6
> diff -p -c -r1.6 utils-gen.scm
> *** utils-gen.scm 14 Nov 2001 19:46:43 -0000 1.6
> --- utils-gen.scm 19 Jun 2002 00:10:20 -0000
> ***************
> *** 116,125 ****
>
> (define (-gen-extract-word word-name word-start word-length start length
> unsigned? lsb0?)
> ! ; ??? lsb0?
> ! (let ((word-end (+ word-start word-length))
> ! (end (+ start length))
> ! (base (if (< start word-start) word-start start)))
> (string-append "("
> "EXTRACT_"
> (if (current-arch-insn-lsb0?) "LSB0" "MSB0")
> --- 116,131 ----
>
> (define (-gen-extract-word word-name word-start word-length start length
> unsigned? lsb0?)
> ! ; Canonicalize on the low and high numbered ends of the field; use the
> ! ; lsb?-adjusted numbering only when necessary.
> ! (let* ((field-low (if lsb0? (- start length) start))
> ! (field-high (if lsb0? start (+ start length)))
> ! (word-low word-start)
> ! (word-high (+ word-start word-length))
> ! ; The field part within the extracted word.
> ! (fieldpart-low (if (< field-low word-low) 0 (- field-low word-low)))
> ! (fieldpart-high (if (> field-high word-high)
> ! word-length (- field-high word-low))))
> (string-append "("
> "EXTRACT_"
> (if (current-arch-insn-lsb0?) "LSB0" "MSB0")
> ***************
> *** 133,148 ****
> ", "
> (number->string word-length)
> ", "
> ! (number->string (if (< start word-start)
> ! 0
> ! (- start word-start)))
> ", "
> ! (number->string (if (< end word-end)
> ! (- end base)
> ! (- word-end base)))
> ") << "
> ! (number->string (if (> end word-end)
> ! (- end word-end)
> 0))
> ")"))
> )
> --- 139,150 ----
> ", "
> (number->string word-length)
> ", "
> ! (number->string (if lsb0? fieldpart-high fieldpart-low))
> ", "
> ! >>>>>>> (number->string (+ 1 (- fieldpart-high fieldpart-low)))
> ") << "
> ! (number->string (if (> field-high word-high)
> ! (- field-high word-high)
> 0))
> ")"))
> )
Are you sure you want the +1 here (grep for >>>)?
I didn't study the lsb0? = #t case, but for lsb0? = #f I compared the old/new
equations on paper and you don't want the +1.
I'm guessing the same would be true for lsb0? = #t.
[unless of course you rework the fieldpart high/low calculations]