f2xm1

science_man_88 · 2010-05-11, 13:05

according to the art of assembly language second edition copyright 2010 this instruction calculates 2^ST0-1 but this only works for 3 integer values should we try and eliminate that limitation and help gimps with a loop using it ?

jasonp · 2010-05-11, 13:26

Um, how would GIMPS benefit from generating strings of all-1 quickly?

science_man_88 · 2010-05-11, 13:35

not just generating using them lucas lehmer used mod Mp if I remember right.

Dougal · 2010-05-11, 13:39

read this first.

http://en.wikipedia.org/wiki/Lucas%E...primality_test

science_man_88 · 2010-05-11, 13:43

I get I'm an idiot I was just asking.

Dougal · 2010-05-11, 13:45

reading the link wont do any harm then.

science_man_88 · 2010-05-11, 13:50

916 mod 2⁵-1 = 1110010100₂ mod 2⁵-1
= 11100₂ + 10100₂ mod 2⁵-1
= 110000₂ mod 2⁵-1
= 1₂ + 10000₂ mod 2⁵-1
= 10001₂ mod 2⁵-1
= 10001₂
= 17.

is basically what my limit helps me understand.

cheesehead · 2010-05-11, 17:09

Quote:

Originally Posted by science_man_88

916 mod 25−1 = 11100101002 mod 25−1

< snip >

You can display exponents by using the [ sup ] and [ /sup ] commands.

2⁵-1

science_man_88 · 2010-05-11, 17:44

Quote:

Originally Posted by cheesehead

You can display exponents by using the [ sup ] and [ /sup ] commands.

2⁵-1

I got that from the article as is.

Mini-Geek · 2010-05-11, 18:06

Quote:

Originally Posted by science_man_88

I got that from the article as is.

They included the <sub> and <sup> (on this forum that'd be [sub] and [sup]) tags necessary, they just weren't copied, since the browser didn't know just how to mark that in the field you were copying to. You could be a bit more careful, and at least include something like _ and ^ if not sub and sup. If you have the forum text editor in one of the right modes for it, there're even sub and sup buttons, that look like 2³ and 2₃, at the right end of the buttons.

science_man_88 · 2010-05-11, 22:23

yeah I didn't see that and forgot BTW if anyone has "the art of assembly" the second edition has this command on p.402 if you'd like to check it out.

"If ST0 is out of range,f2xml generates an undefined result but raises no exceptions. The computed value replaces the value in ST0."

so if we could get this to be understood and turned into the proper math we might be able to cut out a few lines(with my luck probably not).

2010-05-11, 13:05	#1
science_man_88 "Forget I exist" Jul 2009 Dumbassville 8384₁₀ Posts	f2xm1 according to the art of assembly language second edition copyright 2010 this instruction calculates 2^ST0-1 but this only works for 3 integer values should we try and eliminate that limitation and help gimps with a loop using it ?

2010-05-11, 13:39	#4
Dougal Jan 2009 Ireland 2×3×31 Posts	read this first. http://en.wikipedia.org/wiki/Lucas%E...primality_test Last fiddled with by Dougal on 2010-05-11 at 13:40

2010-05-11, 13:50	#7
science_man_88 "Forget I exist" Jul 2009 Dumbassville 2⁶·131 Posts	916 mod 2⁵-1 = 1110010100₂ mod 2⁵-1 = 11100₂ + 10100₂ mod 2⁵-1 = 110000₂ mod 2⁵-1 = 1₂ + 10000₂ mod 2⁵-1 = 10001₂ mod 2⁵-1 = 10001₂ = 17. is basically what my limit helps me understand. Last fiddled with by ewmayer on 2010-05-11 at 21:13 Reason: You're welcome...

2010-05-11, 13:26	#2
jasonp Tribal Bullet Oct 2004 2×3×19×31 Posts	Um, how would GIMPS benefit from generating strings of all-1 quickly?

2010-05-11, 13:35	#3
science_man_88 "Forget I exist" Jul 2009 Dumbassville 8384₁₀ Posts	not just generating using them lucas lehmer used mod Mp if I remember right.

2010-05-11, 13:43	#5
science_man_88 "Forget I exist" Jul 2009 Dumbassville 10000011000000₂ Posts	I get I'm an idiot I was just asking.

2010-05-11, 13:45	#6
Dougal Jan 2009 Ireland 2×3×31 Posts	reading the link wont do any harm then.

2010-05-11, 22:23	#11
science_man_88 "Forget I exist" Jul 2009 Dumbassville 8384₁₀ Posts	yeah I didn't see that and forgot BTW if anyone has "the art of assembly" the second edition has this command on p.402 if you'd like to check it out. "If ST0 is out of range,f2xml generates an undefined result but raises no exceptions. The computed value replaces the value in ST0." so if we could get this to be understood and turned into the proper math we might be able to cut out a few lines(with my luck probably not).