1const ffs = @import("count0bits.zig");
  2const testing = @import("std").testing;
  3
  4fn test__ffsdi2(a: u64, expected: i32) !void {
  5    const x = @as(i64, @bitCast(a));
  6    const result = ffs.__ffsdi2(x);
  7    try testing.expectEqual(expected, result);
  8}
  9
 10test "ffsdi2" {
 11    try test__ffsdi2(0x00000000_00000001, 1);
 12    try test__ffsdi2(0x00000000_00000002, 2);
 13    try test__ffsdi2(0x00000000_00000003, 1);
 14    try test__ffsdi2(0x00000000_00000004, 3);
 15    try test__ffsdi2(0x00000000_00000005, 1);
 16    try test__ffsdi2(0x00000000_00000006, 2);
 17    try test__ffsdi2(0x00000000_00000007, 1);
 18    try test__ffsdi2(0x00000000_00000008, 4);
 19    try test__ffsdi2(0x00000000_00000009, 1);
 20    try test__ffsdi2(0x00000000_0000000A, 2);
 21    try test__ffsdi2(0x00000000_0000000B, 1);
 22    try test__ffsdi2(0x00000000_0000000C, 3);
 23    try test__ffsdi2(0x00000000_0000000D, 1);
 24    try test__ffsdi2(0x00000000_0000000E, 2);
 25    try test__ffsdi2(0x00000000_0000000F, 1);
 26    try test__ffsdi2(0x00000000_00000010, 5);
 27    try test__ffsdi2(0x00000000_00000011, 1);
 28    try test__ffsdi2(0x00000000_00000012, 2);
 29    try test__ffsdi2(0x00000000_00000013, 1);
 30    try test__ffsdi2(0x00000000_00000014, 3);
 31    try test__ffsdi2(0x00000000_00000015, 1);
 32    try test__ffsdi2(0x00000000_00000016, 2);
 33    try test__ffsdi2(0x00000000_00000017, 1);
 34    try test__ffsdi2(0x00000000_00000018, 4);
 35    try test__ffsdi2(0x00000000_00000019, 1);
 36    try test__ffsdi2(0x00000000_0000001A, 2);
 37    try test__ffsdi2(0x00000000_0000001B, 1);
 38    try test__ffsdi2(0x00000000_0000001C, 3);
 39    try test__ffsdi2(0x00000000_0000001D, 1);
 40    try test__ffsdi2(0x00000000_0000001E, 2);
 41    try test__ffsdi2(0x00000000_0000001F, 1);
 42    try test__ffsdi2(0x00000000_00000020, 6);
 43    try test__ffsdi2(0x00000000_00000021, 1);
 44    try test__ffsdi2(0x00000000_00000022, 2);
 45    try test__ffsdi2(0x00000000_00000023, 1);
 46    try test__ffsdi2(0x00000000_00000024, 3);
 47    try test__ffsdi2(0x00000000_00000025, 1);
 48    try test__ffsdi2(0x00000000_00000026, 2);
 49    try test__ffsdi2(0x00000000_00000027, 1);
 50    try test__ffsdi2(0x00000000_00000028, 4);
 51    try test__ffsdi2(0x00000000_00000029, 1);
 52    try test__ffsdi2(0x00000000_0000002A, 2);
 53    try test__ffsdi2(0x00000000_0000002B, 1);
 54    try test__ffsdi2(0x00000000_0000002C, 3);
 55    try test__ffsdi2(0x00000000_0000002D, 1);
 56    try test__ffsdi2(0x00000000_0000002E, 2);
 57    try test__ffsdi2(0x00000000_0000002F, 1);
 58    try test__ffsdi2(0x00000000_00000030, 5);
 59    try test__ffsdi2(0x00000000_00000031, 1);
 60    try test__ffsdi2(0x00000000_00000032, 2);
 61    try test__ffsdi2(0x00000000_00000033, 1);
 62    try test__ffsdi2(0x00000000_00000034, 3);
 63    try test__ffsdi2(0x00000000_00000035, 1);
 64    try test__ffsdi2(0x00000000_00000036, 2);
 65    try test__ffsdi2(0x00000000_00000037, 1);
 66    try test__ffsdi2(0x00000000_00000038, 4);
 67    try test__ffsdi2(0x00000000_00000039, 1);
 68    try test__ffsdi2(0x00000000_0000003A, 2);
 69    try test__ffsdi2(0x00000000_0000003B, 1);
 70    try test__ffsdi2(0x00000000_0000003C, 3);
 71    try test__ffsdi2(0x00000000_0000003D, 1);
 72    try test__ffsdi2(0x00000000_0000003E, 2);
 73    try test__ffsdi2(0x00000000_0000003F, 1);
 74    try test__ffsdi2(0x00000000_00000040, 7);
 75    try test__ffsdi2(0x00000000_00000041, 1);
 76    try test__ffsdi2(0x00000000_00000042, 2);
 77    try test__ffsdi2(0x00000000_00000043, 1);
 78    try test__ffsdi2(0x00000000_00000044, 3);
 79    try test__ffsdi2(0x00000000_00000045, 1);
 80    try test__ffsdi2(0x00000000_00000046, 2);
 81    try test__ffsdi2(0x00000000_00000047, 1);
 82    try test__ffsdi2(0x00000000_00000048, 4);
 83    try test__ffsdi2(0x00000000_00000049, 1);
 84    try test__ffsdi2(0x00000000_0000004A, 2);
 85    try test__ffsdi2(0x00000000_0000004B, 1);
 86    try test__ffsdi2(0x00000000_0000004C, 3);
 87    try test__ffsdi2(0x00000000_0000004D, 1);
 88    try test__ffsdi2(0x00000000_0000004E, 2);
 89    try test__ffsdi2(0x00000000_0000004F, 1);
 90    try test__ffsdi2(0x00000000_00000050, 5);
 91    try test__ffsdi2(0x00000000_00000051, 1);
 92    try test__ffsdi2(0x00000000_00000052, 2);
 93    try test__ffsdi2(0x00000000_00000053, 1);
 94    try test__ffsdi2(0x00000000_00000054, 3);
 95    try test__ffsdi2(0x00000000_00000055, 1);
 96    try test__ffsdi2(0x00000000_00000056, 2);
 97    try test__ffsdi2(0x00000000_00000057, 1);
 98    try test__ffsdi2(0x00000000_00000058, 4);
 99    try test__ffsdi2(0x00000000_00000059, 1);
100    try test__ffsdi2(0x00000000_0000005A, 2);
101    try test__ffsdi2(0x00000000_0000005B, 1);
102    try test__ffsdi2(0x00000000_0000005C, 3);
103    try test__ffsdi2(0x00000000_0000005D, 1);
104    try test__ffsdi2(0x00000000_0000005E, 2);
105    try test__ffsdi2(0x00000000_0000005F, 1);
106    try test__ffsdi2(0x00000000_00000060, 6);
107    try test__ffsdi2(0x00000000_00000061, 1);
108    try test__ffsdi2(0x00000000_00000062, 2);
109    try test__ffsdi2(0x00000000_00000063, 1);
110    try test__ffsdi2(0x00000000_00000064, 3);
111    try test__ffsdi2(0x00000000_00000065, 1);
112    try test__ffsdi2(0x00000000_00000066, 2);
113    try test__ffsdi2(0x00000000_00000067, 1);
114    try test__ffsdi2(0x00000000_00000068, 4);
115    try test__ffsdi2(0x00000000_00000069, 1);
116    try test__ffsdi2(0x00000000_0000006A, 2);
117    try test__ffsdi2(0x00000000_0000006B, 1);
118    try test__ffsdi2(0x00000000_0000006C, 3);
119    try test__ffsdi2(0x00000000_0000006D, 1);
120    try test__ffsdi2(0x00000000_0000006E, 2);
121    try test__ffsdi2(0x00000000_0000006F, 1);
122    try test__ffsdi2(0x00000000_00000070, 5);
123    try test__ffsdi2(0x00000000_00000071, 1);
124    try test__ffsdi2(0x00000000_00000072, 2);
125    try test__ffsdi2(0x00000000_00000073, 1);
126    try test__ffsdi2(0x00000000_00000074, 3);
127    try test__ffsdi2(0x00000000_00000075, 1);
128    try test__ffsdi2(0x00000000_00000076, 2);
129    try test__ffsdi2(0x00000000_00000077, 1);
130    try test__ffsdi2(0x00000000_00000078, 4);
131    try test__ffsdi2(0x00000000_00000079, 1);
132    try test__ffsdi2(0x00000000_0000007A, 2);
133    try test__ffsdi2(0x00000000_0000007B, 1);
134    try test__ffsdi2(0x00000000_0000007C, 3);
135    try test__ffsdi2(0x00000000_0000007D, 1);
136    try test__ffsdi2(0x00000000_0000007E, 2);
137    try test__ffsdi2(0x00000000_0000007F, 1);
138    try test__ffsdi2(0x00000000_00000080, 8);
139    try test__ffsdi2(0x00000000_00000081, 1);
140    try test__ffsdi2(0x00000000_00000082, 2);
141    try test__ffsdi2(0x00000000_00000083, 1);
142    try test__ffsdi2(0x00000000_00000084, 3);
143    try test__ffsdi2(0x00000000_00000085, 1);
144    try test__ffsdi2(0x00000000_00000086, 2);
145    try test__ffsdi2(0x00000000_00000087, 1);
146    try test__ffsdi2(0x00000000_00000088, 4);
147    try test__ffsdi2(0x00000000_00000089, 1);
148    try test__ffsdi2(0x00000000_0000008A, 2);
149    try test__ffsdi2(0x00000000_0000008B, 1);
150    try test__ffsdi2(0x00000000_0000008C, 3);
151    try test__ffsdi2(0x00000000_0000008D, 1);
152    try test__ffsdi2(0x00000000_0000008E, 2);
153    try test__ffsdi2(0x00000000_0000008F, 1);
154    try test__ffsdi2(0x00000000_00000090, 5);
155    try test__ffsdi2(0x00000000_00000091, 1);
156    try test__ffsdi2(0x00000000_00000092, 2);
157    try test__ffsdi2(0x00000000_00000093, 1);
158    try test__ffsdi2(0x00000000_00000094, 3);
159    try test__ffsdi2(0x00000000_00000095, 1);
160    try test__ffsdi2(0x00000000_00000096, 2);
161    try test__ffsdi2(0x00000000_00000097, 1);
162    try test__ffsdi2(0x00000000_00000098, 4);
163    try test__ffsdi2(0x00000000_00000099, 1);
164    try test__ffsdi2(0x00000000_0000009A, 2);
165    try test__ffsdi2(0x00000000_0000009B, 1);
166    try test__ffsdi2(0x00000000_0000009C, 3);
167    try test__ffsdi2(0x00000000_0000009D, 1);
168    try test__ffsdi2(0x00000000_0000009E, 2);
169    try test__ffsdi2(0x00000000_0000009F, 1);
170    try test__ffsdi2(0x00000000_000000A0, 6);
171    try test__ffsdi2(0x00000000_000000A1, 1);
172    try test__ffsdi2(0x00000000_000000A2, 2);
173    try test__ffsdi2(0x00000000_000000A3, 1);
174    try test__ffsdi2(0x00000000_000000A4, 3);
175    try test__ffsdi2(0x00000000_000000A5, 1);
176    try test__ffsdi2(0x00000000_000000A6, 2);
177    try test__ffsdi2(0x00000000_000000A7, 1);
178    try test__ffsdi2(0x00000000_000000A8, 4);
179    try test__ffsdi2(0x00000000_000000A9, 1);
180    try test__ffsdi2(0x00000000_000000AA, 2);
181    try test__ffsdi2(0x00000000_000000AB, 1);
182    try test__ffsdi2(0x00000000_000000AC, 3);
183    try test__ffsdi2(0x00000000_000000AD, 1);
184    try test__ffsdi2(0x00000000_000000AE, 2);
185    try test__ffsdi2(0x00000000_000000AF, 1);
186    try test__ffsdi2(0x00000000_000000B0, 5);
187    try test__ffsdi2(0x00000000_000000B1, 1);
188    try test__ffsdi2(0x00000000_000000B2, 2);
189    try test__ffsdi2(0x00000000_000000B3, 1);
190    try test__ffsdi2(0x00000000_000000B4, 3);
191    try test__ffsdi2(0x00000000_000000B5, 1);
192    try test__ffsdi2(0x00000000_000000B6, 2);
193    try test__ffsdi2(0x00000000_000000B7, 1);
194    try test__ffsdi2(0x00000000_000000B8, 4);
195    try test__ffsdi2(0x00000000_000000B9, 1);
196    try test__ffsdi2(0x00000000_000000BA, 2);
197    try test__ffsdi2(0x00000000_000000BB, 1);
198    try test__ffsdi2(0x00000000_000000BC, 3);
199    try test__ffsdi2(0x00000000_000000BD, 1);
200    try test__ffsdi2(0x00000000_000000BE, 2);
201    try test__ffsdi2(0x00000000_000000BF, 1);
202    try test__ffsdi2(0x00000000_000000C0, 7);
203    try test__ffsdi2(0x00000000_000000C1, 1);
204    try test__ffsdi2(0x00000000_000000C2, 2);
205    try test__ffsdi2(0x00000000_000000C3, 1);
206    try test__ffsdi2(0x00000000_000000C4, 3);
207    try test__ffsdi2(0x00000000_000000C5, 1);
208    try test__ffsdi2(0x00000000_000000C6, 2);
209    try test__ffsdi2(0x00000000_000000C7, 1);
210    try test__ffsdi2(0x00000000_000000C8, 4);
211    try test__ffsdi2(0x00000000_000000C9, 1);
212    try test__ffsdi2(0x00000000_000000CA, 2);
213    try test__ffsdi2(0x00000000_000000CB, 1);
214    try test__ffsdi2(0x00000000_000000CC, 3);
215    try test__ffsdi2(0x00000000_000000CD, 1);
216    try test__ffsdi2(0x00000000_000000CE, 2);
217    try test__ffsdi2(0x00000000_000000CF, 1);
218    try test__ffsdi2(0x00000000_000000D0, 5);
219    try test__ffsdi2(0x00000000_000000D1, 1);
220    try test__ffsdi2(0x00000000_000000D2, 2);
221    try test__ffsdi2(0x00000000_000000D3, 1);
222    try test__ffsdi2(0x00000000_000000D4, 3);
223    try test__ffsdi2(0x00000000_000000D5, 1);
224    try test__ffsdi2(0x00000000_000000D6, 2);
225    try test__ffsdi2(0x00000000_000000D7, 1);
226    try test__ffsdi2(0x00000000_000000D8, 4);
227    try test__ffsdi2(0x00000000_000000D9, 1);
228    try test__ffsdi2(0x00000000_000000DA, 2);
229    try test__ffsdi2(0x00000000_000000DB, 1);
230    try test__ffsdi2(0x00000000_000000DC, 3);
231    try test__ffsdi2(0x00000000_000000DD, 1);
232    try test__ffsdi2(0x00000000_000000DE, 2);
233    try test__ffsdi2(0x00000000_000000DF, 1);
234    try test__ffsdi2(0x00000000_000000E0, 6);
235    try test__ffsdi2(0x00000000_000000E1, 1);
236    try test__ffsdi2(0x00000000_000000E2, 2);
237    try test__ffsdi2(0x00000000_000000E3, 1);
238    try test__ffsdi2(0x00000000_000000E4, 3);
239    try test__ffsdi2(0x00000000_000000E5, 1);
240    try test__ffsdi2(0x00000000_000000E6, 2);
241    try test__ffsdi2(0x00000000_000000E7, 1);
242    try test__ffsdi2(0x00000000_000000E8, 4);
243    try test__ffsdi2(0x00000000_000000E9, 1);
244    try test__ffsdi2(0x00000000_000000EA, 2);
245    try test__ffsdi2(0x00000000_000000EB, 1);
246    try test__ffsdi2(0x00000000_000000EC, 3);
247    try test__ffsdi2(0x00000000_000000ED, 1);
248    try test__ffsdi2(0x00000000_000000EE, 2);
249    try test__ffsdi2(0x00000000_000000EF, 1);
250    try test__ffsdi2(0x00000000_000000F0, 5);
251    try test__ffsdi2(0x00000000_000000F1, 1);
252    try test__ffsdi2(0x00000000_000000F2, 2);
253    try test__ffsdi2(0x00000000_000000F3, 1);
254    try test__ffsdi2(0x00000000_000000F4, 3);
255    try test__ffsdi2(0x00000000_000000F5, 1);
256    try test__ffsdi2(0x00000000_000000F6, 2);
257    try test__ffsdi2(0x00000000_000000F7, 1);
258    try test__ffsdi2(0x00000000_000000F8, 4);
259    try test__ffsdi2(0x00000000_000000F9, 1);
260    try test__ffsdi2(0x00000000_000000FA, 2);
261    try test__ffsdi2(0x00000000_000000FB, 1);
262    try test__ffsdi2(0x00000000_000000FC, 3);
263    try test__ffsdi2(0x00000000_000000FD, 1);
264    try test__ffsdi2(0x00000000_000000FE, 2);
265    try test__ffsdi2(0x00000000_000000FF, 1);
266
267    try test__ffsdi2(0x00000000_00000000, 0);
268    try test__ffsdi2(0x80000000_00000000, 64);
269    try test__ffsdi2(0x40000000_00000000, 63);
270    try test__ffsdi2(0x20000000_00000000, 62);
271    try test__ffsdi2(0x10000000_00000000, 61);
272    try test__ffsdi2(0x08000000_00000000, 60);
273    try test__ffsdi2(0x04000000_00000000, 59);
274    try test__ffsdi2(0x02000000_00000000, 58);
275    try test__ffsdi2(0x01000000_00000000, 57);
276    try test__ffsdi2(0x00800000_00000000, 56);
277    try test__ffsdi2(0x00400000_00000000, 55);
278    try test__ffsdi2(0x00200000_00000000, 54);
279    try test__ffsdi2(0x00100000_00000000, 53);
280    try test__ffsdi2(0x00080000_00000000, 52);
281    try test__ffsdi2(0x00040000_00000000, 51);
282    try test__ffsdi2(0x00020000_00000000, 50);
283    try test__ffsdi2(0x00010000_00000000, 49);
284    try test__ffsdi2(0x00008000_00000000, 48);
285    try test__ffsdi2(0x00004000_00000000, 47);
286    try test__ffsdi2(0x00002000_00000000, 46);
287    try test__ffsdi2(0x00001000_00000000, 45);
288    try test__ffsdi2(0x00000800_00000000, 44);
289    try test__ffsdi2(0x00000400_00000000, 43);
290    try test__ffsdi2(0x00000200_00000000, 42);
291    try test__ffsdi2(0x00000100_00000000, 41);
292    try test__ffsdi2(0x00000080_00000000, 40);
293    try test__ffsdi2(0x00000040_00000000, 39);
294    try test__ffsdi2(0x00000020_00000000, 38);
295    try test__ffsdi2(0x00000010_00000000, 37);
296    try test__ffsdi2(0x00000008_00000000, 36);
297    try test__ffsdi2(0x00000004_00000000, 35);
298    try test__ffsdi2(0x00000002_00000000, 34);
299    try test__ffsdi2(0x00000001_00000000, 33);
300
301    try test__ffsdi2(0x00000000_80000000, 32);
302    try test__ffsdi2(0x00000000_40000000, 31);
303    try test__ffsdi2(0x00000000_20000000, 30);
304    try test__ffsdi2(0x00000000_10000000, 29);
305    try test__ffsdi2(0x00000000_08000000, 28);
306    try test__ffsdi2(0x00000000_04000000, 27);
307    try test__ffsdi2(0x00000000_02000000, 26);
308    try test__ffsdi2(0x00000000_01000000, 25);
309    try test__ffsdi2(0x00000000_00800000, 24);
310    try test__ffsdi2(0x00000000_00400000, 23);
311    try test__ffsdi2(0x00000000_00200000, 22);
312    try test__ffsdi2(0x00000000_00100000, 21);
313    try test__ffsdi2(0x00000000_00080000, 20);
314    try test__ffsdi2(0x00000000_00040000, 19);
315    try test__ffsdi2(0x00000000_00020000, 18);
316    try test__ffsdi2(0x00000000_00010000, 17);
317    try test__ffsdi2(0x00000000_00008000, 16);
318    try test__ffsdi2(0x00000000_00004000, 15);
319    try test__ffsdi2(0x00000000_00002000, 14);
320    try test__ffsdi2(0x00000000_00001000, 13);
321    try test__ffsdi2(0x00000000_00000800, 12);
322    try test__ffsdi2(0x00000000_00000400, 11);
323    try test__ffsdi2(0x00000000_00000200, 10);
324    try test__ffsdi2(0x00000000_00000100, 9);
325}