[RFA:] Fix for lsb0? in -gen-extract-word, take 2.

[Hans-Peter Nilsson <hp@bitrange.com>]

Here's a less intrusive fix since I couldn't wrap my head around
what adjustment there should be for the "<<" expression.  I
can't figure out whether it actually has lsb0?-issues at all, so
I'll not touch it.  Again, only tested on the CRIS (wip) target.

Ok to commit?

	* utils-gen.scm (-gen-extract-word): Handle lsb0?.

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	25 Jun 2002 01:20:12 -0000
***************
*** 114,146 ****
  ; Subroutine of -gen-ifld-extract-beyond to extract the relevant value
  ; from WORD-NAME and move it into place.

! (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")
  		   (if (and (not unsigned?)
  			    ; Only want sign extension for word with sign bit.
! 			    (bitrange-overlap? start 1 word-start word-length
  					       lsb0?))
  		       "_INT ("
  		       "_UINT (")
  		   word-name
  		   ", "
  		   (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))
--- 114,158 ----
  ; Subroutine of -gen-ifld-extract-beyond to extract the relevant value
  ; from WORD-NAME and move it into place.

! (define (-gen-extract-word word-name word-start word-length
! 			   field-start field-length
  			   unsigned? lsb0?)
!   (let* ((word-end (+ word-start word-length))
! 	 (start (if lsb0? (+ 1 (- field-start field-length)) field-start))
! 	 (end (+ start field-length))
! 	 (base (if (< start word-start) word-start start)))
      (string-append "("
  		   "EXTRACT_"
  		   (if (current-arch-insn-lsb0?) "LSB0" "MSB0")
  		   (if (and (not unsigned?)
  			    ; Only want sign extension for word with sign bit.
! 			    (bitrange-overlap? field-start 1
! 					       word-start word-length
  					       lsb0?))
  		       "_INT ("
  		       "_UINT (")
+ 		   ; What to extract from.
  		   word-name
  		   ", "
+ 		   ; Size of this chunk.
  		   (number->string word-length)
  		   ", "
! 		   ; MSB of this piece.
! 		   (number->string
! 		    (if lsb0?
! 			(if (> end word-end)
! 			    (- word-end 1)
! 			    (- end word-start 1))
! 			(if (< start word-start)
! 			    0
! 			    (- start word-start))))
  		   ", "
+ 		   ; Length of field within this chunk.
  		   (number->string (if (< end word-end)
  				       (- end base)
  				       (- word-end base)))
  		   ") << "
+ 		   ; Adjustment for this piece within a full field.
  		   (number->string (if (> end word-end)
  				       (- end word-end)
  				       0))

brgds, H-P