Can an instruction ever have a jump and assignment?

[AlexKrel]

Like the title says, can they both be in one instruction.

When the instruction map is show it is shown like this

dest = comp ; jmp

But this form never occurs in any of the given assembly programs.

[AlexKrel]

Finished part 1 of the course!

I've been experimenting with my question now that my assembler is done.
You can definitely use destination and jump bits together.

[AlexKrel]

The think the reason you don't see any destination and jump bit combinations in any of the sample codes is because there is almost no practical reason to ever use a statement like

@23
M = D ; JEQ.

Since instructions are taken from ROM and data is stored in RAM, when you use a statement like the one above, you are storing the value of D in in RAM address 23 while jumping to ROM address 23 (if the D value is 0).

A trivial program

@8
D = A
@R0
M = D; JMP

Here, we store the value 8 in D, set A to 0 and then store the value in D in RAM 0, while also jumping back to ROM 0 to start the program over again...So it's possible but it's hard to see a reason to use these kinds of statements.

Let me know if you can find a use for a statement like this.

[ivant]

I think a fairly advanced optimizer could use this kind of instruction to shave off several instructions, but probably it would only account for bragging :)

[cadet1620]

The general pattern

        D=<something that doesn't use A or M>
    @SOMEWHERE
        0;JMP

can have the D= merged into the jump.

For example, at the bottom of a loop:

    @LOOP
        D=D-1;JGT

But as Ivan said, this is mostly just a trick to save one instruction.

You might also find this thread interesting. It's about jump instructions that change the A register.

--Mark