SYSRUTH@utorphys.bitnet (Ruth Milner, Systems Manager x2746) (02/01/89)
In v7n114 I reported that: >The Sun 4 (all models) FPU is not an option, but an integral part of the >CPU that does all floating-point operations. My apologies; this is wrong. On Sun 4/110's the FPU *is* an option. On Sun 4/2x0's it is not (or at least, it isn't listed as such on my price list). I can think of two ways to determine whether you have an FPU. The first one is a visual check of the hardware, i.e. whether or not the chips are there. The second, if you need to be able to check from a program, is to check the EF bit in the %psr register. This reports whether the FPU is enabled/disabled (enabled but not present should = disabled, but you may need to attempt a simple fp operation and trap the fp_disabled exception). I have reason to believe there will be better utilities in the near future, analogous to the Sun 3 fpaversion program, but don't know when these will be generally available. See Ch. 3 of the SPARC Architecture manual for details. Thanks to Sam Finn and Bruce Barnett for pointing this out to me. I hope my mistake did not cause any problems for anyone. Ruth Milner Systems Manager University of Toronto Physics sysruth@helios.physics.utoronto.ca