On Sat, 5 Apr 2003 05:00:10 -0600, Phil Howard <[EMAIL PROTECTED]> wrote:
>On Fri, Apr 04, 2003 at 06:51:43PM -0600, Lucius, Leland wrote: > >| > > For instance, calling BZ2_bzBuffToBuffCompress() would >| > require you >| > > to reserve the standard 96 bytes, plus 8 more since it has 7 >| > > parameters. So: >| > > >| > > L R15,Stkptr Get address of stack >| > > AL R15,=F'4096' Point to end of stack >| > > SL R15,=F'104' Reserve first frame >| > >| > These last two seem equivalent to >| > LA 4096-104(,R15) >| > and faster (no storage reference) and 12 bytes shorter. >| > >| > Okay, I'll stop here;-) >| > >| Except that it was only an example to illustrate usage. The 4096 was the >| stack size and might need to be enlarged based on compression routines used. > >Still, you can combine the AL and SL to a single AL with pre-computed >difference. Then switch to LA when it's less than 4096. That is true for most circumstances. One difference is that in 31 bit mode bit 0 is cleared and in 24 bit mode bits 0-7 are cleared. That would not be true with the AL/SL instructions. Bit 0 might be important information in some circumstances. john
