hello gurus

how to convert a huge negative or positive 128 bit number or above from decimal to hexadecimal using only 486 32 bit instructions set?

You need to create your own set of bignum routines, capable to add digit to bit number, and capable to multiply big number by 10.

Then you must convert decimal number to bignumr: set big num X to 0, and go from low (last) to high (first) digit of decimal number. For each digit, multiply x by 10, and then add value of digit to x. When you are done with that, converting binary big number to hex is very easy, just one hex digit per 4 bits of big number.

About manipulation with bignums, see this article: http://x86asm.net/articles/working-with-big-numbers-using-x86-instructions/index.html

Wouldn't that reverse the number? 12345 would become bignum 54321. In 4bit increments is 1101 0100 0011 0001 which is D431 in hex, but 12345 in hex is 3039. Or am I missing something?

use miracl and do not reinvent the wheel

Accumulate digits to a larger (like 10^9) base then merge with BIGINT for speed. Wheels should be reinvented because the roads are changing...

i suggest to use square wheels if so

There are roads where square wheels would be optimal!