From: Spiro Trikaliotis (trik-news_at_gmx.de)
Date: 2003-03-10 10:21:27
Hello, David Holz wrote: > What I meant is if there's a good 6502 FP library available that doesn't use > exactly the IEEE binary representation. For instance, my math lib that I've > been messing around with for some time has the exponent as the number of > bytes (instead of bits) to shift, and I normalize the highest mantissa byte > to non-zero instead of having the implied "1" hanging off the end. Saves a > load of bit-shifting, but I add another byte onto the mantissa to maintain > precision. Plus, I haven't finished it so it's as of yet unproven, but I > think it's got good potential as a different, faster way of doing FP on the > 6502. Yes, it is faster, but it is not binary FP anymore, this is hexadecimal FP. And this has some severe disadvantages which I don't remember anymore. For those interested, have a look at Donald E. Knuth: TAOCP, Vol. 2: "Seminumerical Algorithms". > > The C standard does not require fp math functions to raise a signal on an > > error condition. But it requires that the a math function returns an > > implementation defined value, so these error conditions have to be > > detected > > and handled in some way. > > Right, so SIGFPE is Posix or somesuch, but you can implement any error > mechanism you want (well, besides crashing ;) ) and still be C compliant? yes, an error mechanism could even be "doing nothing". Spiro. ---------------------------------------------------------------------- To unsubscribe from the list send mail to majordomo_at_musoftware.de with the string "unsubscribe cc65" in the body(!) of the mail.
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