XBR4D76H@DDATHD21.BITNET (07/23/87)
In article <8707150100.AA13525@ucbvax.Berkeley.EDU>, SADOIAN@UOFT02.BITNET writes: > Has anyone else noticed that GEMBOOT screws up GFA BASIC's edit screen? I noticed this effect too, but located GFA-BASIC as the "bad guy", not GEMBOOT. GFA-BASIC manipulates the video screen base, and the bug is produced by a difference between the software screen base (system variable _v_bas_ad) and the "physical" (controller internal) screen base. The controller internal screen base is restricted to 256 byte page bounderies. Unfortunately GFA-BASIC calculates an unbounded address, probably influenced by GEMBOOT allocating it's cache blocks at the memory top. The VDI and AES drawing routines are using the software base and therefore all output is shifted. As the screen memory is scan line organized this leads to a rotation of the screen image. Konrad A. Hahn BITNET: XBR4D76H@DDATHD21