Bitwise manipulation: reversing bit order

Bome Products
1

Oh poo - I coded myself into a painted corner! LOL

is there an easy way to reverse bit order in a variable?
That is:
1100 → 0011
0100 → 0010
etc

I figure I could just set up 2 local variables as counters, have one count down, one count up, and go bit by bit comparing the original counting up each bit position and flipping the bits on a destination variable counting down each bit position.

Been searching online for maybe some majiks, but everything seems to end up on a C++ tutorial page using functions we don’t have access to.

2

Yes, not easy,

The logic you outlines makes sense to me, however I’m not sure why you would ever want to do this. I’ve never encountered a use case for this type of bit manipulation.

Steve Caldwell
Bome Customer Care

Also available for paid consulting services: bome@sniz.biz
3

This should work but always be very careful when using loops in rules that you don’t create an infinite loop and lock up MT Pro

ga=124
// reverse bits in ga and put back in ga
rr=0

pp=0
tt=31-pp
Label "Loop"

// get bit
ss=ga>>pp
ss=ss&1
uu=ss<<tt
rr=rr|uu
pp=pp+1
tt=31-pp
if pp<32 then goto "Loop"
// done , put it in ga

ga=rr

Steve Caldwell
Bome Customer Care

Also available for paid consulting services: bome@sniz.biz
4

thanks Steve!

I just popped back on here to share what I came up with. Excellent! Thank you!

Yes, I do weird things, but this is because I didn’t know where I was going when I started coding this section, and let’s say buttons that I relate to on my side as 1 → 4 are, under the hood, bits 4 → 1.
So, I either flip the bit order or rewrite stuff I wrote a long time ago which will take me weeks to figure out what I did. LOL

5

Yes, I get it. I’ve painted (coded) myself into a corner more than once as well.

Steve Caldwell
Bome Customer Care

Also available for paid consulting services: bome@sniz.biz