In message <[EMAIL PROTECTED]>, Matthew Dillon wri tes:
> In anycase, I think this is reasonable especially if we explicitly > use the fast code for those chipsets known to be good. I would like > to commit it. It can handle *ANY* sort of ripple or fast-carry breakage, > really any type of breakage since it looks for two identical samples > after masking rather then using an inequality. My only worry here is laptops. If my laptop is connected to the wall-power when it boots it comes up at full CPU speed during the probe and mask determination. Then I unplug it and the CPU speed drops by a large factor and suddenly the mask is too tight for the CPU to get two samples. I think we need an approach where we loosen the mask at runtime if some significant number of iterations fail to get a count may be needed: #define N 25 static unsigned mask = 0xfffffffe; for (;;) { for (i = 0; i < N; i++) { c = READ_TIMER & mask; d = READ_TIMER & mask; if (c == d) return(d); } printf("Adjusting mask to %08x\n", mask); mask <<= 1; } -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message