Slc5

I am trying to do something the easy way, which I think can be done but I don't know how.
I have a 16 bit register that will give me four groups of four bits depending on the equipment installed.
Bits 0-3 are ignored, 4-7 will give me a value, 8-11 will give me another value, and 12-15 another value.
Each group will be decimal value 2, 3, or 4 in binary.
Can I convert each group of bits to a decimal value while ignoring the rest?
I would then use the HMI to display which equipment was installed.

thanks

Research the TOD instruction

Brute force method.

For the numeric value in bits 4 - 7:
(Original_Word AND x00F0) / 16

For the numeric value in bits 8 - 11:
(Original_Word AND x0F00) / 256

For the numeric value in bits 12 - 15:
(Original_Word AND xF000) / 4096

The AND function zeroes all bits except for the ones you're interested in.
The divide function shifts the bits toward the least significant by the number of places represented by the power of 2.

Steve Bailey's solution is what I would suggest, although you can use MVM instead of AND if you like.

Unfortunately BTD is not supported in a SLC, or I would use that instead of division.

Steve Bailey said:

Brute force method.

For the numeric value in bits 4 - 7:
(Original_Word AND x00F0) / 16

For the numeric value in bits 8 - 11:
(Original_Word AND x0F00) / 256

For the numeric value in bits 12 - 15:
(Original_Word AND xF000) / 4096

The AND function zeroes all bits except for the ones you're interested in.
The divide function shifts the bits toward the least significant by the number of places represented by the power of 2.

Click to expand...

Perhaps those should all be 7s (0x0070; 0x0700; 0x7000), which works because OP said the values will be 2, 3, or 4; if not, then the last one should be:A brute-force option isEsoteric (i.e. ugly) version, assuming possible values are only ever 2 or 3 or 4, saves 3 instructions over brute-force:But with no BTD, @Steve Bailey's method is probably the cleanest.

in a slc 500, bit 15 is the sign bit, so you my have trouble in that respect.
james

The FRD and TOD instructions to translate to and from Binary Coded Decimal do exist in the SLC-500 operating system, but you still have to add a bunch of buffer data table elements and divide by 10, 100, 1000 and use the S:13 and S:14 math registers to get the remainders.

I would do this by jumping to a subroutine with nothing but four XIC's and four OTE's for each value. It's brute-force, but it's fast and it's easy for a future user to understand even if the comments are lost.

Dividing by 16, 256, and 4096 also works because the value of a nibble is never more than 4, so the Sign bit in the 16-bit signed integer source word is never true. But it's not a general-purpose solution.