PixelPerfectEngine.audio.firFilter source code

1 module PixelPerfectEngine.audio.firFilter;
2 
3 /*
4  * Copyright (C) 2015-2018, by Laszlo Szeremi under the Boost license.
5  *
6  * Pixel Perfect Engine, FIR filter module
7  */
8 
9 public struct FiniteImpulseResponse(int L){
10 	//static assert(L % 2 == 0);
11 	public short[L] vals;
12 }
13 
14 public struct FiniteImpulseResponseFilter(int L){
15 	FiniteImpulseResponse!L* impulseResponse;
16 	private short[L + 3] delayLine;
17 	private uint stepping;
18 	private uint truncating;
19 	this(FiniteImpulseResponse!L* impulseResponse){
20 		this.impulseResponse = impulseResponse;
21 		version(X86){
22 			truncating = (L * 8) - 1;
23 		}else version(X86_64){
24 			truncating = (L * 8) - 1;
25 		}else{
26 			truncating = L - 1;
27 		}
28 	}
29 	/*public @nogc int calculate(short input){
30 		if(stepping < 3){
31 			delayLine[L + (L - stepping)] = input;
32 		}
33 		delayLine[L - stepping] = input;
34 		version(X86){
35 			int[4] result;
36 			asm @nogc{
37 				mov		ESI, impulseResponse[EBP];
38 				mov		EDI, delayLine[EBP];
39 				mov		EDX, stepping;
40 				mov		EAX, truncating;
41 				mov		ECX, L;
42 
43 			filterloop:
44 				mov		EBX, EDX;
45 				and		EBX, EAX;
46 				add		EBX, EDI;
47 				movups	XMM0, [EBX];
48 				movups	XMM1, [ESI];
49 				pmaddwd	XMM1, XMM0;
50 				paddd	XMM2, XMM1;
51 				add		ESI, 16;
52 				add		EDX, 16;
53 				dec		ECX;
54 				cmp		ECX, 0;
55 				jnz		filterloop;
56 				movups	result, XMM2;
57 			}
58 			stepping++;
59 			stepping &= truncating;
60 			return result[0] + result[1] + result[2] + result[3];
61 		}else version(X86_64){
62 			int[4] result;
63 			asm @nogc{
64 				mov		RSI, impulseResponse[RBP];
65 				mov		RDI, delayLine[RBP];
66 				mov		EDX, stepping;
67 				mov		EAX, truncating;
68 				mov		ECX, L;
69 
70 			filterloop:
71 				mov		RBX, RDX;
72 				and		RBX, RAX;
73 				add		RBX, RDI;
74 				movups	XMM0, [RBX];
75 				movups	XMM1, [RSI];
76 				mulps	XMM1, XMM0;
77 				addps	XMM2, XMM1;
78 				add		RSI, 16;
79 				add		RDX, 16;
80 				dec		ECX;
81 				cmp		ECX, 0;
82 				jnz		filterloop;
83 				movups	result, XMM2;
84 			}
85 			stepping++;
86 			stepping &= truncating;
87 			return result[0] + result[1] + result[2] + result[3];
88 		}else{
89 			int result;
90 			for(int i; i < L; i++){
91 				result += delayLine[(i + stepping) & truncating] * impulseResponse.vals[i];
92 			}
93 			stepping++;
94 			stepping &= truncating;
95 		}
96 		
97 	}*/
98 }