🚀 go-pugleaf

In article <5@wb1.cs.cmu.edu] avie@wb1.cs.cmu.edu (Avadis Tevanian) writes:
] In article <1531@husc6.UUCP] reiter@harvard.UUCP (Ehud Reiter) writes:
]] As a brief addition to my previous posting, when I used my own strcpy and strcmp
]] routines, the Dhrystone rating of my microVAX II (cc -O, 4.3BSD) jumped from
]] 1000 (library strcpy, strcmp) to 1400 (my strcpy, strcmp).
] You've got to be careful when you run benchmarks.  If you are indeed running
] 4.3, then you are most likely using the 4.3 libc, which has been carefully
] optimized to use the fancy VAX instructions for the string routines.
] Unfortunately, some of these instructions are not implemented by the
] MicroVAX-II hardware.  As it turns out, what is happening is that your tests
] (including Dhrystone) are causing kernel traps to emulate those
] instructions!

The fix, of course, is:
	o Have the startup module determine what version of the CPU is running
	  and set a global.
	o Have the string functions use different instruction sequences,
	  depending on which CPU is being used.
This is similar to how the 8087 is used on the PC.