Re: Event struct via registers

[Vitaliy Fadeev via Digitalmars-d-learn]

On Saturday, 10 August 2024 at 07:46:46 UTC, Vitaliy Fadeev wrote:
## Trouble 1
Pass the structure through registers ?

## Trouble 2

Wrap the registries in a structure ?
How to implement on D?

I try:
```
import std.stdio;

void
main() {
        Event_1 event_1;
        event (event_1);

        Event_2 event_2;
        event (event_2);
}

struct
Event_1 {
    ushort type  = 1;
    ushort code  = 2;
    uint   value = 3;
}

struct
Event_2 {
    ushort type  = 1;
    ushort code  = 2;
    uint   value = 3;
    float  x = 4.0;
    float  y = 5.0;
}


void
event (EVENT) (/* R this, */ EVENT e) {
    enum REG_SIZE = (void*).sizeof; // Bytes
    pragma (msg, EVENT, " : ", EVENT.sizeof);
    pragma (msg, "REG_SIZE: ", REG_SIZE);
    static if (EVENT.sizeof == 0) {
        //
    }
    else
    static if (EVENT.sizeof <= REG_SIZE) {  //  64 bit
        _event (/* this, */
            * cast (REG*) &e,
            //* cast (REG*) cast (ubyte*) &e,
            //cast (REG) *(
            //  (cast (ubyte*) &e)[0..EVENT.sizeof].ptr
            //),
            0,
            0);
    }
    else
    static if (EVENT.sizeof <= 2*REG_SIZE) {  // 128 bit
        _event (/* this, */
            cast (REG) *(
                (cast (ubyte*) &e)[0..REG_SIZE].ptr
            ),
            cast (REG) *(
                (cast (ubyte*) &e)[REG_SIZE..EVENT.sizeof].ptr
            ),
            0);
    }
    else
        static assert (0, "Event sizeof too much");
}

alias REG = ulong;

void
_event (/* REG this, */ REG type_code_value, REG r3, REG r4) {
    //switch (type_code_value.type) {
    //    case Event.Type.GUI: gui.event (type_code_value, r3, 
r4); break;
    //    default:
    //}
    writeln ("type_code_value: ", type_code_value);
    writeln ("r3: ", r3);
    writeln ("r4: ", r4);

    Event_1 event_1;
    event_1 = * cast (Event_1*) &type_code_value;

    writeln ("  event_1 :", event_1);

    if (r3 != 0) {
        writeln ("  event_2 :", r3);
    }
}
```

But i have 0 in r3.
I need help converting the structure `Event_2` into 2 `ulong` 
parameters `type_code_value`, `r3`.