Pointless challenge: 6502 wordsquares, 3x3

[BigEd]

On the cover of the classic Advanced User Guide (for the BBC Micro) by Bray, Dickens, and Holmes, we find this:



Or, in letters:

Code: Select all

BCC
PLP
LDY

You'll notice 6 mnemonics interleaved. Are there more ways to do this? Many more, or just one or two? Is it easy to find them? Fancy writing a program to find them all??

Here's a bit of whitespace, just in case there are spoilers below.

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[BitWise]

Challenge accepted. I'll be back.

[BitWise]

BitWise wrote:

Challenge accepted. I'll be back.

There are more than you'd expect. Results in the two trace files (in the zip) for the 6502 and 65C02.

[BigEd]

That was quick! Well done! And not so very many - but enough to be interesting - with 6 distinct opcodes.

[BitWise]

BigEd wrote:

That was quick! Well done! And not so very many - but enough to be interesting - with 6 distinct opcodes.

Its a quiet day in the code mine.

[BigEd]

Now I'm imagining you chiselling code onto stone tablets...

[BitWise]

BigEd wrote:

Now I'm imagining you chiselling code onto stone tablets...

Some days it feels like that.

[John West]

If we insist on six different instructions and ignore transposition, there are only two solutions. The second isn't hard to find, given the first.

Respect to whoever came up with that design.