ccc_ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) (07/08/90)
I hit a problem with the Viewer 1.05 program on the System 7.0a9 CD-ROM; on some of the Inside Mac Volume VI chapters, the vertical scroll bar was inactive, regardless of the window size, so I could only see the top part of the first page. The chapters were fairly large, so I knew there was more than one page to see. The funny thing was, there were other chapters, both larger and smaller, that would display properly. I tracked down the problem to some 32-bit arithmetic that was sign-extending 16-bit values instead of padding them out with zeroes. I came up with the following patch, that seems to work fine. In CODE resource number 1, look for the following sequence: 302C 0024 ; move.w $0024(a4), d0 D06B FFF8 ; add.w -8(a3), d0 5340 ; subq.w #1, d0 48C0 ; ext.l d0 and replace it with: 7000 ; moveq #0, d0 302C 0024 ; move.w $0024(a4), d0 D06B FFF8 ; add.w -8(a3), d0 5340 ; subq.w #1, d0 That is, just delete the sign-extension instruction at the end, and put a zero-extension instruction at the front. You can do this patch quite easily with ResEdit. Lawrence D'Oliveiro fone: +64-71-562-889 Computer Services Dept fax: +64-71-384-066 University of Waikato electric mail: ldo@waikato.ac.nz Hamilton, New Zealand 37^ 47' 29" S, 175^ 19' 16" E, GMT+12:00 "...so she tried to break into the father bear's computer, but it was too hard. Then she tried to break into the mother bear's computer, but that was too easy..."