aglew@ccvaxa.UUCP (02/20/87)
>Another "problem" with Dhrystone which is also present in Dhampstone >is that since they are single file programs they are subject to >certain optimizations possible for machines with large numbers >of registers such as allocating blocks of registers to procedures, >and a different block of registers to the procedure it calls. > >The Stanford MIPS guys are looking at this. But this technique >doesn't work too well on large real programs which either recurse >or are multiple program files compiled separately and then >linked together. > >Jan Stubbs ....sdcsvax!ncr-sd!stubbs Unless registers are actually only bound at link time. NOPping out the register save instructions would be trivial, and not cost too much. Besides, this sounds a lot like old FORTRAN, with fixed parameter areas in memory. When memory was too small, overlay. I read a paper that seemed to imply that Cray was attempting something similar. Has anything more come of this? Andy "Krazy" Glew. Gould CSD-Urbana. USEnet: ihnp4!uiucdcs!ccvaxa!aglew 1101 E. University, Urbana, IL 61801 ARPAnet: aglew@gswd-vms.arpa
bcase@amdcad.UUCP (02/23/87)
In article <28200008@ccvaxa> aglew@ccvaxa.UUCP writes: >Unless registers are actually only bound at link time. >NOPping out the register save instructions would be trivial, >and not cost too much. >I read a paper that seemed to imply that Cray was attempting something >similar. Has anything more come of this? > >Andy "Krazy" Glew. Gould CSD-Urbana. USEnet: ihnp4!uiucdcs!ccvaxa!aglew >1101 E. University, Urbana, IL 61801 ARPAnet: aglew@gswd-vms.arpa Re: Binding/allocating registers at link time. See a *very* good paper by Wall in the Summer SIGPLAN conference on Compiler Construction. This paper describes a method to get the performance benefit of a stack-cache style register file (e.g. Berekely register windows) from a fixed set of registers (e.g. almost anything else). This work was done for the DEC Titan RISC machine with excellent results (but hey, the machine has 64 registers). bcase --------- Keep watching this space!