@@ -45,10 +45,155 @@ T atan(T x) {
4545};
4646
4747template <typename T>
48- T atan2 (T x) {
49- return (T) hls::atan2 (x);
48+ T atan2 (T x, T y ) {
49+ return (T) hls::atan2 (x, y );
5050};
5151
52+ template <class T , int W, int I>
53+ void init_sincos_table (T table[1 <<(W - I - 3 )][2]) {
54+ unsigned int NTE = 1 <<(W - I - 3 ); // No of table entries
55+ double step = M_PI/(4 *NTE); // Interval between angles
56+ double y = 0 ;
57+ // double scaled_angle = 0;
58+
59+ for (unsigned int i=0 ; i < NTE; i++) {
60+ table[i][0 ] = std::cos (y);
61+ table[i][1 ] = std::sin (y);
62+ y += step;
63+ // scaled_angle = y/(2*M_PI);
64+ // printf("cos(%f) = %23.22f, sin(%f) = %23.22f index = %d, scaled angle = %13.12f \n", y, cos(y), y, sin(y), i, scaled_angle);
65+ }
66+
67+ }
68+
69+ template <class T >
70+ void sincos_lut (const T &input, T output[2 ]) {
71+
72+ #pragma HLS INLINE
73+
74+ static bool flag = true ;
75+ if (flag && T::width-T::iwidth > 12 ) {
76+ #if !defined(__SYNTHESIS__) && defined(SINCOS_LUT_DEBUG)
77+ std::cout << " FILE : " " , LINE : "
78+ std::cout << " Warning: The output of sincos_lut will not be accurate"
79+ #endif
80+ flag = false ;
81+ }
82+ // Datatype for lookup table entries
83+ typedef ap_ufixed <T::width, T::iwidth, AP_RND> luttype;
84+ // Datatype for posinput which is used to handle negative inputs
85+ typedef ap_ufixed<T::width-T::iwidth, 0 > posinputtype;
86+
87+ typedef ap_uint<9 > lutindextype; // 9 bits required for indexing into 512 entry table
88+ typedef ap_uint<3 > octanttype; // 3 bits required for octant value range of 0 thru 7
89+ T outputtemp[2 ];
90+ lutindextype luTdex = 0 ;
91+ posinputtype posinput = input;
92+
93+ // Initialize the lookup table
94+ #ifdef __SYNTHESIS__
95+ bool initialized = false ;
96+ luttype sincos[512 ][2 ];
97+ #else
98+ static bool initialized = false ;
99+ static luttype sincos[512 ][2 ];
100+ #endif
101+ if (!initialized) {
102+ init_sincos_table<luttype, 12 , 0 >(sincos);
103+ initialized = true ;
104+ }
105+
106+ // Leaving this commented out makes the table to to BRAM
107+ // #pragma HLS ARRAY_PARTITION variable=sincos complete dim=0
108+
109+ typedef ap_uint<AP_MAX (T::width-T::iwidth-3 , 1 )> lutindextype1;
110+ // Extracting (MSB-3:LSB) bits of scaled input to determine the lookup table index
111+ lutindextype1 luTdex1 = posinput.range (AP_MAX (T::width-T::iwidth-3 , 1 ), 0 ); // Extracting the lookup table index
112+
113+ if (T::width-T::iwidth>=4 && T::width-T::iwidth<=12 ) {
114+ luTdex (8 , 12 - (T::width - T::iwidth)) = luTdex1; // stride
115+ }
116+ // Approximation for the scaled inputs whose number of bits are greater than 12
117+ else if (T::width-T::iwidth>12 ) {
118+ // Lookup table index for the scaled inputs whose number of bits are greater than 12
119+ luTdex = luTdex1/(1 <<(AP_MAX (T::width-T::iwidth-12 , 0 )));
120+ if ((luTdex1 % (1 <<(AP_MAX (T::width-T::iwidth-12 ,0 )))) > (1 <<(AP_MAX (T::width-T::iwidth-13 ,0 )))) {
121+ luTdex = luTdex + 1 ;
122+ }
123+ typedef ap_ufixed<AP_MAX ((AP_MAX (T::width-T::iwidth-3 , 1 ) + T::width-T::iwidth-12 ), 1 ), AP_MAX (T::width-T::iwidth-3 , 1 )> datatype;
124+ datatype x = (datatype)luTdex1;
125+ x = x >> AP_MAX (T::width-T::iwidth-12 , 0 );
126+ if (x > 511.5 ) { luTdex = 511 ; }
127+ if (luTdex1 <= 1 <<(AP_MAX (T::width-T::iwidth-13 ,0 )) && luTdex1 != 0 ) { luTdex = 1 ; }
128+ }
129+
130+ if (T::width-T::iwidth>=3 ) {
131+ // Getting the octant 0-7 by extracting the first 3 bits from MSB side of scaled input where
132+ // octant 0 corresponds to [0-PI/4),
133+ // octant 1 corresponds to [PI/4-2PI/4),
134+ // octant 2 corresponds to [2PI/4-3PI/4) and so on
135+ // octanttype octant = posinput.template slc<3>(T::width-T::iwidth-3);
136+ octanttype octant = posinput (T::width-T::iwidth-1 , T::width-T::iwidth-3 );
137+ luTdex = (octant[0 ] == 1 )?(lutindextype)(512 -luTdex):(lutindextype)(luTdex);
138+ // imaginary part is sine
139+ outputtemp[1 ] = ((octant==0 ) | (octant==3 )) ? (T) sincos[luTdex][1 ]:
140+ ((octant==2 ) | (octant==1 )) ? (T) sincos[luTdex][0 ]:
141+ ((octant==7 ) | (octant==4 )) ? (T)-sincos[luTdex][1 ]:
142+ (T)-sincos[luTdex][0 ];
143+ // real part is cosine
144+ outputtemp[0 ] = ((octant==6 ) | (octant==1 )) ? (T) sincos[luTdex][1 ]:
145+ ((octant==3 ) | (octant==4 )) ? (T)-sincos[luTdex][0 ]:
146+ ((octant==2 ) | (octant==5 )) ? (T)-sincos[luTdex][1 ]:
147+ (T) sincos[luTdex][0 ];
148+ // Below two are the cases when the output corresponds to + or - (0 or 1) for which there is no entry in the lookup table
149+ output[1 ] = ((posinput==0.125 ) | (posinput==0.375 )) ? T ( 0.7071067811865475244008 ):
150+ ((posinput==0.625 ) | (posinput==0.875 )) ? T (-0.7071067811865475244008 ):
151+ outputtemp[1 ];
152+ output[0 ] = ((posinput==0.125 ) | (posinput==0.875 )) ? T ( 0.7071067811865475244008 ):
153+ ((posinput==0.375 ) | (posinput==0.625 )) ? T (-0.7071067811865475244008 ):
154+ outputtemp[0 ];
155+ }
156+
157+ if (T::width-T::iwidth <= 2 ) {
158+ output[1 ] = (posinput==0 ) ? (T) 0 :
159+ (posinput==0.25 ) ? (T) 1 :
160+ (posinput==0.5 ) ? (T) 0 :
161+ (posinput==0.75 ) ? (T)-1 :
162+ outputtemp[1 ];
163+ output[0 ] = (posinput==0 ) ? (T) 1 :
164+ (posinput==0.25 ) ? (T) 0 :
165+ (posinput==0.5 ) ? (T)-1 :
166+ (posinput==0.75 ) ? (T) 0 :
167+ outputtemp[0 ];
168+ }
169+
170+ #if !defined(__SYNTHESIS__) && defined(SINCOS_LUT_DEBUG)
171+ std::cout << " FILE : " " , LINE : "
172+ std::cout << " ============AP_FIXED SINCOS======================"
173+ std::cout << " positive input is = "
174+ std::cout << " lut index is = "
175+ std::cout << " sin value is = " 1 ] << std::endl;
176+ std::cout << " cos value is = " 0 ] << std::endl;
177+ std::cout << " ================================================="
178+ #endif
179+ }
180+
181+ template <class T >
182+ T sin_lut (const T input) {
183+ T sincos_res[2 ];
184+ T scaled_input = input * ap_ufixed<16 ,0 >(0.15915494309 ); // 1/(2*pi)
185+ sincos_lut (scaled_input, sincos_res);
186+ return sincos_res[1 ];
187+ }
188+
189+ template <class T >
190+ T cos_lut (const T input) {
191+ T sincos_res[2 ];
192+ T scaled_input = input * ap_ufixed<16 ,0 >(0.15915494309 ); // 1/(2*pi)
193+ sincos_lut (scaled_input, sincos_res);
194+ return sincos_res[0 ];
195+ }
196+
52197}
53198
54- #endif
199+ #endif
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