tutorial - from sm primitives to code to asm

Nu Audio Science · 21 Apr 2009

When you say all math do you mean just stream math right ? Not green math I'm a little confused on that

Oh and thanks for the tutorial 😉

NAS

hansdump · 21 Apr 2009

Nice Tutorial. Newbies will be happy!!

H.

AlexT · 21 Apr 2009

Thanks for that. It's a nice tutorial and certainly helps those of us that no nothing or very little about ASM. 🙂

Neptune · 21 Apr 2009

hansdump wrote: Nice Tutorial. Newbies will be happy!! H.

Yes, i'm really happy about it Thanks a lot!! But how about a little complexer example like this

I tried to do it in code but failed as expected 🙂

MichaelBenjamin · 21 Apr 2009

yes this is a bit harder. look at the end - something gets added to left and substracted to right (its the result of the multiplication)

so lets say the result of the multiplication is x

out1=in1+x; out2=in2-x;

so what is x?

x is something multiplied with the dezipper, so x=y*dezip now y: y is left input minus something, so y=in1-z

almost there, now its easy, because z is (left+right)/5 - note that you need the parentheses because first left and right needs to be aded, then the result is divided. now you can write: y: in1-((in1+in2)/5) and x: (in1-((in1+in2)/5))*dezip

and now as code: streamin in1; streamin in2; streamin amount; //was dezip, but amount makes more sense streamout out1; streamout out2; float mix;//temp variable to store the number that gets added and substracted

mix=(in1-((in1+in2)/5))*amount; out1= in1+mix; out2= in2-mix;

as an additional optimisation you can exchange divisions with constants by a multiplication with 1/constant, this saves cpu time so instead of /5, write *0.2

mix=(in1-((in1+in2)*0.2))*amount; out1= in1+mix; out2= in2-mix;

Nu Audio Science · 23 Apr 2009

just used this to shave some CPU out of one of my schematics, only simple stuff I combined a balance and auto balancer and converted to ASM then converted my stereo wet/dry to ASM cheers for this MB has given me a tiny understanding of ASM

NAS

Nu Audio Science · 27 Apr 2009

You know what i just done some heavy duty tests and to be honest i wish i had kept the coded versions over the ASM versions for some of my plugs because compiled the ASM is using significantly more CPU than the ASM And that is a straight 1:1 code to ASM comparison If i can find the coded versions in an older save on my drive i will put together a comparison OSM but i have to be honest at this point i dont think the 1:1 code to ASM thing is of any use at all I would guess you need to heavily optomise the ASM once copied to even get close to the straight code in these examples

NAS

aliasant · 27 Apr 2009

Nu Audio Science wrote: You know what i just done some heavy duty tests and to be honest i wish i had kept the coded versions over the ASM versions for some of my plugs because compiled the ASM is using significantly more CPU than the ASM And that is a straight 1:1 code to ASM comparison If i can find the coded versions in an older save on my drive i will put together a comparison OSM but i have to be honest at this point i dont think the 1:1 code to ASM thing is of any use at all I would guess you need to heavily optomise the ASM once copied to even get close to the straight code in these examples

NAS

Hmm. SOmething is wrong. When I take a code block, convert it to asm and optimize it I at least save 40%. Often more. If I can combine several code blocks into one before optimizing it I will save even more.

Edit: I read you ENTIRE post now 😉. Yes. Code to ASm 1:1 doesnt do anything. Not that I know of. Its not until you start optimizing it that you see the gains.

Update: Heres an example of what I did today.

I had the original RMS code that someone made. Sorry. Cant remember who.

It uses 78.2 on my machine. It is 4 channels and 2 blocks of code. Not very efficient. Now I only needed 1 channel since Im using it for mono so I converted it to asm, ripped out 3 channels, optimized some + added the squareroot part in the same asm block. The new one now uses 43 cycles so I gained 35 cycles on that. And as others have mentioned, it makes the code run more stable. Im planning to combine this part with several other parts and I think that will save me even more on this project 🙂

Here is the Mono RMS code. Maybe someone can optimize it even further?

streamin in; streamout out; float smIntVarTemp=0.0; int smIntVarArrayIndex=0; float smIntVarZero=0; float arymax=255; float n=0; float acum=0; float in2=0; float F0=0; float F256=256; float F1=1; float ary[256]; movaps xmm3,F0; movaps xmm7,in; mulps xmm7,xmm7; movaps in2,xmm7; addps xmm7,acum; movaps xmm6,n; maxps xmm6,smIntVarZero; minps xmm6,arymax; cvtps2dq xmm6,xmm6; movaps smIntVarArrayIndex,xmm6; push eax; mov eax,smIntVarArrayIndex[0]; shl eax,4; fld ary[eax]; fstp smIntVarTemp[0]; movaps xmm1,smIntVarTemp; pop eax; subps xmm7,xmm1; maxps xmm7,xmm3; movaps acum,xmm7; movaps xmm4,n; maxps xmm4,smIntVarZero; minps xmm4,arymax; cvtps2dq xmm4,xmm4; movaps smIntVarArrayIndex,xmm4; push eax; mov eax,smIntVarArrayIndex[0]; shl eax,4; fld in2[0]; fstp ary[eax]; pop eax; divps xmm7,F256; movaps xmm0,n; addps xmm0,F1; movaps n,xmm0; mov eax,ecx; and eax,255; cmp eax,0; jnz end0; movaps n,xmm3; end0: sqrtps xmm1,xmm7; movaps out,xmm1;

infuzion · 28 Apr 2009

aliasant wrote: Here is the Mono RMS code. Maybe someone can optimize it even further?

... divps xmm7,F256;...

Maybe acum/256 = aculm*(1/256)?

MyCo · 28 Apr 2009

@aliasant: in the code you removed the other 3 SSE channels, so it won't work on a polyphone system

aliasant · 28 Apr 2009

MyCo wrote: @aliasant: in the code you removed the other 3 SSE channels, so it won't work on a polyphone system

Lol. Yes. I said so in my post too. I only needed a mono version.

MyCo · 28 Apr 2009

damn... haven't read it... too much text 😈

aliasant · 28 Apr 2009

MyCo wrote: damn... haven't read it... too much text 😈

LOL Sorry 🙂

robrokken · 30 Aug 2009

This is really great stuff! I'm just at the point of learning whats actually inside the code boxes!!!

Excellent!

Rob.