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16 bit signed multiply for 6502?


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#1 Gorf OFFLINE  

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Posted Mon Jan 4, 2010 8:35 PM

Any one have a decent efficient 6502 alg for 16 bit signed multiplies?
Thanks.

#2 GroovyBee OFFLINE  

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Posted Tue Jan 5, 2010 5:57 AM

View PostGorf, on Mon Jan 4, 2010 8:35 PM, said:

Any one have a decent efficient 6502 alg for 16 bit signed multiplies?

Discussion about 6502 multiplication here :-

http://www.atariage....multiplication/

If you can find a copy of "Best of PCW Assembler Routines for the 6502" by David Barrow there is a 16x16 unsigned routine in there. You'd need to convert your input values to unsigned first. If you can't find the source code for the book online (its from 1985) I'll type it in.

#3 Gorf OFFLINE  

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Posted Wed Jan 6, 2010 11:28 AM

View PostGroovyBee, on Tue Jan 5, 2010 5:57 AM, said:

View PostGorf, on Mon Jan 4, 2010 8:35 PM, said:

Any one have a decent efficient 6502 alg for 16 bit signed multiplies?

Discussion about 6502 multiplication here :-

http://www.atariage....multiplication/

If you can find a copy of "Best of PCW Assembler Routines for the 6502" by David Barrow there is a 16x16 unsigned routine in there. You'd need to convert your input values to unsigned first. If you can't find the source code for the book online (its from 1985) I'll type it in.

Turns out I dont need it..I found another way to handle the sign but thanks for the link. :)




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