• Bogdan (28/28) Sep 21 2019 I'm trying to understand how to use the `core.simd`
• Bogdan (19/19) Sep 21 2019 Here's a cleaned up version:
• Bogdan (2/12) Sep 21 2019 Not sure if it's correct though.
• Stefan Koch (7/19) Sep 21 2019 float4 x;
• Bogdan (5/26) Oct 06 2019 Thank you! That also seems to be working.
• NaN (3/31) Oct 06 2019 You should probably have a look at this...
• Bogdan (4/6) Oct 06 2019 Thanks, that looks quite useful.

Bogdan <olar.bogdan.dev gmail.com> writes:

I'm trying to understand how to use the `core.simd` 
functionality, and I'm having trouble initializing a float4 
vector.

Here's my example code:

```
import std.stdio;
import core.simd;

void main()
{
   float[4] values = [1.0f, 2.0f, 3.0f, 4.0f];
   float delta = 15.0f;

   writeln(doSimd(values, delta));

}

float[4] doSimd(float[4] values, float delta)
{
   float4 v_delta = delta;
   float4 v_values = values;

   // ... do SIMD ...

   return [v_delta[0], v_delta[0],v_delta[0],v_delta[0]];
}
```

Compilation is failing with the following error:

```
source/app.d(16,21): Error: cannot implicitly convert expression 
values of type float[4] to __vector(float[4])
dmd failed with exit code 1.
```
How do you initialize a float4 with some useful data?

Bogdan <olar.bogdan.dev gmail.com> writes:

Here's a cleaned up version:

```
import std.stdio;
import core.simd;

void main()
{
   float[4] values = [1.0f, 2.0f, 3.0f, 4.0f];
   float delta = 15.0f;

   writeln(doSimd(values, delta));

}

float[4] doSimd(float[4] values, float delta)
{
   float4 v_delta = delta;
   float4 v_values = values;

   v_values = __simd(XMM.ADDPS, v_values, v_delta);

   return [v_values[0], v_values[1],v_values[2],v_values[3]];
}
```

The problem is with initializing v_values.

Bogdan <olar.bogdan.dev gmail.com> writes:

Well, this seems to be working:

 float[4] doSimd(float[4] values, float delta)
 {
   float4 v_delta = delta;
 
   float4 v_values = __simd(XMM.ADDPS,
                            __simd(XMM.LODAPS, values[0]),
                            v_delta);
 
   return [v_values[0], v_values[1],v_values[2],v_values[3]];
 }

Not sure if it's correct though.

Stefan Koch <uplink.coder googlemail.com> writes:

On Saturday, 21 September 2019 at 13:42:09 UTC, Bogdan wrote:
 Well, this seems to be working:

 float[4] doSimd(float[4] values, float delta)
 {
   float4 v_delta = delta;
 
   float4 v_values = __simd(XMM.ADDPS,
                            __simd(XMM.LODAPS, values[0]),
                            v_delta);
 
   return [v_values[0], v_values[1],v_values[2],v_values[3]];
 }

 Not sure if it's correct though.

float4 x;
float x1, x2, x3, x4;
x[0] = x1;
x[1] = x2;
x[2] = x3;
x[3] = x4;

Bogdan <olar.bogdan.dev gmail.com> writes:

On Saturday, 21 September 2019 at 14:31:15 UTC, Stefan Koch wrote:
 On Saturday, 21 September 2019 at 13:42:09 UTC, Bogdan wrote:
 Well, this seems to be working:

 float[4] doSimd(float[4] values, float delta)
 {
   float4 v_delta = delta;
 
   float4 v_values = __simd(XMM.ADDPS,
                            __simd(XMM.LODAPS, values[0]),
                            v_delta);
 
   return [v_values[0], v_values[1],v_values[2],v_values[3]];
 }

 Not sure if it's correct though.

 float4 x;
 float x1, x2, x3, x4;
 x[0] = x1;
 x[1] = x2;
 x[2] = x3;
 x[3] = x4;

Thank you! That also seems to be working.
Turns out that using this method for drawing a rectangle is about 
twice as slow than a naive implementation, so I'm almost 
certainly doing something silly/wrong. :)

NaN <divide by.zero> writes:

On Saturday, 21 September 2019 at 12:50:46 UTC, Bogdan wrote:
 I'm trying to understand how to use the `core.simd` 
 functionality, and I'm having trouble initializing a float4 
 vector.

 Here's my example code:

 ```
 import std.stdio;
 import core.simd;

 void main()
 {
   float[4] values = [1.0f, 2.0f, 3.0f, 4.0f];
   float delta = 15.0f;

   writeln(doSimd(values, delta));

 }

 float[4] doSimd(float[4] values, float delta)
 {
   float4 v_delta = delta;
   float4 v_values = values;

   // ... do SIMD ...

   return [v_delta[0], v_delta[0],v_delta[0],v_delta[0]];
 }
 ```

 Compilation is failing with the following error:

 ```
 source/app.d(16,21): Error: cannot implicitly convert 
 expression values of type float[4] to __vector(float[4])
 dmd failed with exit code 1.
 ```
 How do you initialize a float4 with some useful data?

You should probably have a look at this...

https://github.com/AuburnSounds/intel-intrinsics

Bogdan <olar.bogdan.dev gmail.com> writes:

On Sunday, 6 October 2019 at 11:53:29 UTC, NaN wrote:
 You should probably have a look at this...

 https://github.com/AuburnSounds/intel-intrinsics

Thanks, that looks quite useful.
Also, it seems that I need to use either LDC or GDC instead of 
DMD. :)