I'm trying to make sense of doubles (64 bit). Basically I want to add/subtract/multiply/divide 64-bit integers. But I have no idea how to do any of this. I've heard that the FPU has instructions that can handle 64-bit math, but I've never used the FPU instructions (and have no idea what they are!). If anyone has sample code that shows how to do any of these things, please share it!

Try bitrake's snipplet

http://www.bitrake.com/phpBB2/topic.php?t=62

I think using fpu for 64bit integer maths is a bad idea

you may wish to employ some of the newer registers, sorry, I have no experience with them, but I believe they are 128 bits wide. Regards, tom

tom: yes, they are, but they are purposed to work with multiple number at the same time, not on one big. MMX is for integers (whole numbers), SSE for floats. FPU works with single floating point numbers.

crc: chapter 8 (maybe 9) of my tuts will be about this, but you probably wouldn't want to wait for it (few month maybe). Anyway, check "adc" and "sbb" instructions about adding and substracting.

Thank you for the pointers. I'm (slowly) starting to make sense of 64 bit numbers. Vid, I'll watch for chapters 8 & 9 of your tutorial; this is one aspect of assembly programming that I'm finding quite confusing :-/

I *think* I have addition and subtraction working now, but I have no idea how to display the result The value is in EDX:EAX Does anyone know how to display this in a console (Linux, FreeBSD, Windows, or BeOS?)

if you want display it decimal, you need division and modulo operations.

by the way, there is something about combining two number into one in my tutorial, maybe it would help.

http://srcvault.scali.eu.org/cgi-bin/Syntax/Syntax.cgi?PrintRadix.asm

Have a look around the source vault, there's a number of useful routines there.

Hi!

Take a look at Randall Hyde's Art of Assembly book. Randall's teaching how to do 64bit and 128bit math. That could help you.

Regards
Mac2004