char-fork/llama.cpp

git clone https://git.t4t.associates/char-fork/llama.cpp

Pasha KhosraviCUDA: add Q2_0 support (#25707)9b2a08881

char/aliceai-t5-moe
17.2 KiB452 linesraw
1#include "common.cuh"
2#include "convert.cuh"
3
4static __device__ __forceinline__ void dequantize_q1_0(const void * vx, const int64_t ib, const int iqs, float2 & v){
5    const block_q1_0 * x = (const block_q1_0 *) vx;
6
7    const float d = x[ib].d;
8
9    const int bit_index_0 = iqs;
10    const int bit_index_1 = iqs + 1;
11
12    const int byte_index_0 = bit_index_0 / 8;
13    const int bit_offset_0 = bit_index_0 % 8;
14
15    const int byte_index_1 = bit_index_1 / 8;
16    const int bit_offset_1 = bit_index_1 % 8;
17
18    // Extract bits: 1 = +d, 0 = -d (branchless)
19    const int bit_0 = (x[ib].qs[byte_index_0] >> bit_offset_0) & 1;
20    const int bit_1 = (x[ib].qs[byte_index_1] >> bit_offset_1) & 1;
21
22    v.x = (2*bit_0 - 1) * d;
23    v.y = (2*bit_1 - 1) * d;
24}
25
26static __device__ __forceinline__ void dequantize_q2_0(const void * vx, const int64_t ib, const int iqs, float2 & v){
27    const block_q2_0 * x = (const block_q2_0 *) vx;
28
29    const float d = x[ib].d;
30
31    // Q2_0: 2 bits per element, 4 elements per byte.
32    // Stored code c in {0,1,2,3} maps to symbol s = c - 1 in {-1, 0, +1, +2}.
33    const int byte_index_0 = iqs / 4;
34    const int bit_offset_0 = (iqs % 4) * 2;
35
36    const int byte_index_1 = (iqs + 1) / 4;
37    const int bit_offset_1 = ((iqs + 1) % 4) * 2;
38
39    const int c0 = (x[ib].qs[byte_index_0] >> bit_offset_0) & 0x3;
40    const int c1 = (x[ib].qs[byte_index_1] >> bit_offset_1) & 0x3;
41
42    v.x = (c0 - 1) * d;
43    v.y = (c1 - 1) * d;
44}
45
46static __device__ __forceinline__ void dequantize_q4_0(const void * vx, const int64_t ib, const int iqs, float2 & v){
47    const block_q4_0 * x = (const block_q4_0 *) vx;
48
49    const float d = x[ib].d;
50
51    const int vui = x[ib].qs[iqs];
52
53    v.x = vui & 0xF;
54    v.y = vui >> 4;
55
56    v.x = (v.x - 8.0f) * d;
57    v.y = (v.y - 8.0f) * d;
58}
59
60static __device__ __forceinline__ void dequantize_q4_1(const void * vx, const int64_t ib, const int iqs, float2 & v){
61    const block_q4_1 * x = (const block_q4_1 *) vx;
62
63    const float2 dm = __half22float2(x[ib].dm);
64
65    const int vui = x[ib].qs[iqs];
66
67    v.x = vui & 0xF;
68    v.y = vui >> 4;
69
70    v.x = (v.x * dm.x) + dm.y;
71    v.y = (v.y * dm.x) + dm.y;
72}
73
74static __device__ __forceinline__ void dequantize_q5_0(const void * vx, const int64_t ib, const int iqs, float2 & v){
75    const block_q5_0 * x = (const block_q5_0 *) vx;
76
77    const float d = x[ib].d;
78
79    uint32_t qh;
80    memcpy(&qh, x[ib].qh, sizeof(qh));
81
82    const int xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
83    const int xh_1 = ((qh >> (iqs + 12))     ) & 0x10;
84
85    v.x = ((x[ib].qs[iqs] & 0xf) | xh_0);
86    v.y = ((x[ib].qs[iqs] >>  4) | xh_1);
87
88    v.x = (v.x - 16.0f) * d;
89    v.y = (v.y - 16.0f) * d;
90}
91
92static __device__ __forceinline__ void dequantize_q5_1(const void * vx, const int64_t ib, const int iqs, float2 & v){
93    const block_q5_1 * x = (const block_q5_1 *) vx;
94
95    const float2 dm = __half22float2(x[ib].dm);
96
97    uint32_t qh;
98    memcpy(&qh, x[ib].qh, sizeof(qh));
99
100    const int xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
101    const int xh_1 = ((qh >> (iqs + 12))     ) & 0x10;
102
103    v.x = ((x[ib].qs[iqs] & 0xf) | xh_0);
104    v.y = ((x[ib].qs[iqs] >>  4) | xh_1);
105
106    v.x = (v.x * dm.x) + dm.y;
107    v.y = (v.y * dm.x) + dm.y;
108}
109
110static __device__ __forceinline__ void dequantize_q8_0(const void * vx, const int64_t ib, const int iqs, float2 & v){
111    const block_q8_0 * x = (const block_q8_0 *) vx;
112
113    const float d = x[ib].d;
114
115    v.x = x[ib].qs[iqs + 0];
116    v.y = x[ib].qs[iqs + 1];
117
118    v.x *= d;
119    v.y *= d;
120}
121
122//================================== k-quants
123
124// Each call dequantizes one super-block of QK_K values into y using the
125// thread layout of the caller: 32 threads for q4_K, 64 threads otherwise.
126
127template<typename dst_t>
128static __device__ __forceinline__ void dequantize_q2_K(const void * vx, const int64_t ib, dst_t * yy, const int tid) {
129    const block_q2_K * x = (const block_q2_K *) vx;
130
131    const int64_t n   = tid/32;
132    const int64_t l   = tid - 32*n;
133    const int64_t is  = 8*n + l/16;
134
135    const uint8_t q = x[ib].qs[32*n + l];
136    dst_t * y = yy + 128*n;
137
138    float dall = __low2half(x[ib].dm);
139    float dmin = __high2half(x[ib].dm);
140    y[l+ 0] = ggml_cuda_cast<dst_t>(dall * (x[ib].scales[is+0] & 0xF) * ((q >> 0) & 3) - dmin * (x[ib].scales[is+0] >> 4));
141    y[l+32] = ggml_cuda_cast<dst_t>(dall * (x[ib].scales[is+2] & 0xF) * ((q >> 2) & 3) - dmin * (x[ib].scales[is+2] >> 4));
142    y[l+64] = ggml_cuda_cast<dst_t>(dall * (x[ib].scales[is+4] & 0xF) * ((q >> 4) & 3) - dmin * (x[ib].scales[is+4] >> 4));
143    y[l+96] = ggml_cuda_cast<dst_t>(dall * (x[ib].scales[is+6] & 0xF) * ((q >> 6) & 3) - dmin * (x[ib].scales[is+6] >> 4));
144}
145
146template<typename dst_t>
147static __device__ __forceinline__ void dequantize_q3_K(const void * vx, const int64_t ib, dst_t * yy, const int tid) {
148    const block_q3_K * x = (const block_q3_K *) vx;
149
150    const int64_t r = tid/4;
151    const int64_t t = r/2;
152    const int64_t is0 = r%2;
153    const int64_t l0 = 16*is0 + 4*(tid%4);
154    const int64_t n = t / 4;
155    const int64_t j = t - 4*n;
156
157    uint8_t m = 1 << (4*n + j);
158    int64_t is = 8*n + 2*j + is0;
159    int shift = 2*j;
160
161    int8_t us = is <  4 ? (x[ib].scales[is-0] & 0xF) | (((x[ib].scales[is+8] >> 0) & 3) << 4) :
162                is <  8 ? (x[ib].scales[is-0] & 0xF) | (((x[ib].scales[is+4] >> 2) & 3) << 4) :
163                is < 12 ? (x[ib].scales[is-8] >>  4) | (((x[ib].scales[is+0] >> 4) & 3) << 4) :
164                          (x[ib].scales[is-8] >>  4) | (((x[ib].scales[is-4] >> 6) & 3) << 4);
165    float d_all = x[ib].d;
166    float dl = d_all * (us - 32);
167
168    dst_t * y = yy + 128*n + 32*j;
169    const uint8_t * q = x[ib].qs + 32*n;
170    const uint8_t * hm = x[ib].hmask;
171
172    for (int l = l0; l < l0+4; ++l) {
173        y[l] = ggml_cuda_cast<dst_t>(dl * ((int8_t)((q[l] >> shift) & 3) - ((hm[l] & m) ? 0 : 4)));
174    }
175}
176
177static inline __device__ void get_scale_min_k4(int j, const uint8_t * q, uint8_t & d, uint8_t & m) {
178    if (j < 4) {
179        d = q[j] & 63; m = q[j + 4] & 63;
180    } else {
181        d = (q[j+4] & 0xF) | ((q[j-4] >> 6) << 4);
182        m = (q[j+4] >>  4) | ((q[j-0] >> 6) << 4);
183    }
184}
185
186template<typename dst_t>
187static __device__ __forceinline__ void dequantize_q4_K(const void * vx, const int64_t ib, dst_t * yy, const int tid) {
188    const block_q4_K * x = (const block_q4_K *) vx;
189
190    // assume 32 threads
191    const int64_t il  = tid/8;
192    const int64_t ir  = tid%8;
193    const int64_t is  = 2*il;
194    const int64_t n   = 4;
195
196    dst_t * y = yy + 64*il + n*ir;
197
198    const float dall = __low2half(x[ib].dm);
199    const float dmin = __high2half(x[ib].dm);
200
201    const uint8_t * q = x[ib].qs + 32*il + n*ir;
202
203    uint8_t sc, m;
204    get_scale_min_k4(is + 0, x[ib].scales, sc, m);
205    const float d1 = dall * sc; const float m1 = dmin * m;
206    get_scale_min_k4(is + 1, x[ib].scales, sc, m);
207    const float d2 = dall * sc; const float m2 = dmin * m;
208    for (int l = 0; l < n; ++l) {
209        y[l + 0] = ggml_cuda_cast<dst_t>(d1 * (q[l] & 0xF) - m1);
210        y[l +32] = ggml_cuda_cast<dst_t>(d2 * (q[l] >>  4) - m2);
211    }
212}
213
214template<typename dst_t>
215static __device__ __forceinline__ void dequantize_q5_K(const void * vx, const int64_t ib, dst_t * yy, const int tid) {
216    const block_q5_K * x = (const block_q5_K *) vx;
217
218    // assume 64 threads - this is very slightly better than the one below
219    const int64_t il  = tid/16;   // il is in 0...3
220    const int64_t ir  = tid%16;   // ir is in 0...15
221    const int64_t is  = 2*il;     // is is in 0...6
222
223    dst_t * y = yy + 64*il + 2*ir;
224
225    const float dall = __low2half(x[ib].dm);
226    const float dmin = __high2half(x[ib].dm);
227
228    const uint8_t * ql = x[ib].qs + 32*il + 2*ir;
229    const uint8_t * qh = x[ib].qh + 2*ir;
230
231    uint8_t sc, m;
232    get_scale_min_k4(is + 0, x[ib].scales, sc, m);
233    const float d1 = dall * sc; const float m1 = dmin * m;
234    get_scale_min_k4(is + 1, x[ib].scales, sc, m);
235    const float d2 = dall * sc; const float m2 = dmin * m;
236
237    uint8_t   hm  = 1 << (2*il);
238    y[ 0] = ggml_cuda_cast<dst_t>(d1 * ((ql[ 0] & 0xF) + (qh[ 0] & hm ? 16 : 0)) - m1);
239    y[ 1] = ggml_cuda_cast<dst_t>(d1 * ((ql[ 1] & 0xF) + (qh[ 1] & hm ? 16 : 0)) - m1);
240    hm <<= 1;
241    y[32] = ggml_cuda_cast<dst_t>(d2 * ((ql[ 0] >>  4) + (qh[ 0] & hm ? 16 : 0)) - m2);
242    y[33] = ggml_cuda_cast<dst_t>(d2 * ((ql[ 1] >>  4) + (qh[ 1] & hm ? 16 : 0)) - m2);
243}
244
245template<typename dst_t>
246static __device__ __forceinline__ void dequantize_q6_K(const void * vx, const int64_t ib, dst_t * yy, const int tid) {
247    const block_q6_K * x = (const block_q6_K *) vx;
248
249    // assume 64 threads - this is very slightly better than the one below
250    const int64_t ip  = tid/32;   // ip is 0 or 1
251    const int64_t il  = tid - 32*ip; // 0...32
252    const int64_t is  = 8*ip + il/16;
253
254    dst_t * y = yy + 128*ip + il;
255
256    const float d = x[ib].d;
257
258    const uint8_t * ql = x[ib].ql + 64*ip + il;
259    const uint8_t   qh = x[ib].qh[32*ip + il];
260    const int8_t  * sc = x[ib].scales + is;
261
262    y[ 0] = ggml_cuda_cast<dst_t>(d * sc[0] * ((int8_t)((ql[ 0] & 0xF) | (((qh >> 0) & 3) << 4)) - 32));
263    y[32] = ggml_cuda_cast<dst_t>(d * sc[2] * ((int8_t)((ql[32] & 0xF) | (((qh >> 2) & 3) << 4)) - 32));
264    y[64] = ggml_cuda_cast<dst_t>(d * sc[4] * ((int8_t)((ql[ 0]  >> 4) | (((qh >> 4) & 3) << 4)) - 32));
265    y[96] = ggml_cuda_cast<dst_t>(d * sc[6] * ((int8_t)((ql[32]  >> 4) | (((qh >> 6) & 3) << 4)) - 32));
266}
267
268//================================== i-quants
269
270// Each call dequantizes one super-block of QK_K values into y with 32
271// threads; iq4_nl packs QK_K/QK4_NL sub-blocks per super-block.
272
273template<typename dst_t>
274static __device__ __forceinline__ void dequantize_iq2_xxs(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
275
276    const block_iq2_xxs * x = (const block_iq2_xxs  *) vx;
277
278    const int64_t il = tid/8; // 0...3
279    const int64_t ib = tid%8; // 0...7
280    dst_t * y = yy + 32*ib + 8*il;
281    const uint16_t * q2 = x[ibs].qs + 4*ib;
282    const uint8_t  * aux8 = (const uint8_t *)q2;
283    const uint8_t  * grid = (const uint8_t *)(iq2xxs_grid + aux8[il]);
284    const uint32_t aux32 = q2[2] | (q2[3] << 16);
285    const float d = (float)x[ibs].d * (0.5f + (aux32 >> 28)) * 0.25f;
286    const uint8_t signs = ksigns_iq2xs[(aux32 >> 7*il) & 127];
287    for (int j = 0; j < 8; ++j) {
288        y[j] = ggml_cuda_cast<dst_t>(d * grid[j] * (signs & kmask_iq2xs[j] ? -1.f : 1.f));
289    }
290}
291
292template<typename dst_t>
293static __device__ __forceinline__ void dequantize_iq2_xs(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
294
295    const block_iq2_xs * x = (const block_iq2_xs *) vx;
296
297    const int64_t il = tid/8; // 0...3
298    const int64_t ib = tid%8; // 0...7
299    dst_t * y = yy + 32*ib + 8*il;
300    const uint16_t * q2 = x[ibs].qs + 4*ib;
301    const uint8_t  * grid = (const uint8_t *)(iq2xs_grid + (q2[il] & 511));
302    const float d = (float)x[ibs].d * (0.5f + ((x[ibs].scales[ib] >> 4*(il/2)) & 0xf)) * 0.25f;
303    const uint8_t signs = ksigns_iq2xs[q2[il] >> 9];
304    for (int j = 0; j < 8; ++j) {
305        y[j] = ggml_cuda_cast<dst_t>(d * grid[j] * (signs & kmask_iq2xs[j] ? -1.f : 1.f));
306    }
307}
308
309template<typename dst_t>
310static __device__ __forceinline__ void dequantize_iq2_s(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
311
312    const block_iq2_s * x = (const block_iq2_s *) vx;
313
314    const int64_t il = tid/8; // 0...3
315    const int64_t ib = tid%8; // 0...7
316    dst_t * y = yy + 32*ib + 8*il;
317    const uint8_t * grid = (const uint8_t *)(iq2s_grid + (x[ibs].qs[4*ib+il] | ((x[ibs].qh[ib] << (8-2*il)) & 0x300)));
318    const float d = (float)x[ibs].d * (0.5f + ((x[ibs].scales[ib] >> 4*(il/2)) & 0xf)) * 0.25f;
319    const uint8_t signs = x[ibs].qs[QK_K/8+4*ib+il];
320    for (int j = 0; j < 8; ++j) {
321        y[j] = ggml_cuda_cast<dst_t>(d * grid[j] * (signs & kmask_iq2xs[j] ? -1.f : 1.f));
322    }
323}
324
325template<typename dst_t>
326static __device__ __forceinline__ void dequantize_iq3_xxs(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
327
328    const block_iq3_xxs * x = (const block_iq3_xxs  *) vx;
329
330    const int64_t il = tid/8; // 0...3
331    const int64_t ib = tid%8; // 0...7
332    dst_t * y = yy + 32*ib + 8*il;
333    const uint8_t  * q3 = x[ibs].qs + 8*ib;
334    const uint16_t * gas = (const uint16_t *)(x[ibs].qs + QK_K/4) + 2*ib;
335    const uint8_t  * grid1 = (const uint8_t *)(iq3xxs_grid + q3[2*il+0]);
336    const uint8_t  * grid2 = (const uint8_t *)(iq3xxs_grid + q3[2*il+1]);
337    const uint32_t aux32 = gas[0] | (gas[1] << 16);
338    const float d = (float)x[ibs].d * (0.5f + (aux32 >> 28)) * 0.5f;
339    const uint8_t signs = ksigns_iq2xs[(aux32 >> 7*il) & 127];
340    for (int j = 0; j < 4; ++j) {
341        y[j+0] = ggml_cuda_cast<dst_t>(d * grid1[j] * (signs & kmask_iq2xs[j+0] ? -1.f : 1.f));
342        y[j+4] = ggml_cuda_cast<dst_t>(d * grid2[j] * (signs & kmask_iq2xs[j+4] ? -1.f : 1.f));
343    }
344}
345
346template<typename dst_t>
347static __device__ __forceinline__ void dequantize_iq3_s(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
348
349    const block_iq3_s * x = (const block_iq3_s *) vx;
350
351    const int64_t il = tid/8; // 0...3
352    const int64_t ib = tid%8; // 0...7
353    dst_t * y = yy + 32*ib + 8*il;
354    const uint8_t * qs = x[ibs].qs + 8*ib;
355    const uint8_t * grid1 = (const uint8_t *)(iq3s_grid + (qs[2*il+0] | ((x[ibs].qh[ib] << (8-2*il)) & 256)));
356    const uint8_t * grid2 = (const uint8_t *)(iq3s_grid + (qs[2*il+1] | ((x[ibs].qh[ib] << (7-2*il)) & 256)));
357    const float d = (float)x[ibs].d * (1 + 2*((x[ibs].scales[ib/2] >> 4*(ib%2)) & 0xf));
358    const uint8_t signs = x[ibs].signs[4*ib + il];
359    for (int j = 0; j < 4; ++j) {
360        y[j+0] = ggml_cuda_cast<dst_t>(d * grid1[j] * (signs & kmask_iq2xs[j+0] ? -1.f : 1.f));
361        y[j+4] = ggml_cuda_cast<dst_t>(d * grid2[j] * (signs & kmask_iq2xs[j+4] ? -1.f : 1.f));
362    }
363}
364
365template<typename dst_t>
366static __device__ __forceinline__ void dequantize_iq1_s(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
367
368    const block_iq1_s * x = (const block_iq1_s  *) vx;
369
370    const int64_t il = tid/8; // 0...3
371    const int64_t ib = tid%8; // 0...7
372    dst_t * y = yy + 32*ib + 8*il;
373    const float delta = x[ibs].qh[ib] & 0x8000 ? -1 - IQ1S_DELTA : -1 + IQ1S_DELTA;
374    const float d = (float)x[ibs].d * (2*((x[ibs].qh[ib] >> 12) & 7) + 1);
375    uint32_t grid32[2]; const int8_t * q = (const int8_t *)grid32;
376    grid32[0] = iq1s_grid_gpu[x[ibs].qs[4*ib+il] | (((x[ibs].qh[ib] >> 3*il) & 7) << 8)];
377    grid32[1] = (grid32[0] >> 4) & 0x0f0f0f0f;
378    grid32[0] &= 0x0f0f0f0f;
379    for (int j = 0; j < 8; ++j) {
380        y[j] = ggml_cuda_cast<dst_t>(d * (q[j] + delta));
381    }
382}
383
384template<typename dst_t>
385static __device__ __forceinline__ void dequantize_iq1_m(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
386
387    const block_iq1_m * x = (const block_iq1_m  *) vx;
388
389    const int64_t il = tid/8; // 0...3
390    const int64_t ib = tid%8; // 0...7
391    dst_t * y = yy + 32*ib + 8*il;
392    const uint16_t * sc = (const uint16_t *)x[ibs].scales;
393    iq1m_scale_t scale;
394    scale.u16 = (sc[0] >> 12) | ((sc[1] >> 8) & 0x00f0) | ((sc[2] >> 4) & 0x0f00) | (sc[3] & 0xf000);
395    const int64_t ib16 = 2*ib + il/2; // sc[ib16/4] >> 3*(ib16%4) -> sc[ib/2] >> 3*((2*ib+il/2)%4);
396    const float d = (float)scale.f16 * (2*((sc[ib16/4] >> 3*(ib16%4)) & 0x7) + 1);
397    const float delta = x[ibs].qh[2*ib+il/2] & (0x08 << 4*(il%2)) ? -1 - IQ1M_DELTA : -1 + IQ1M_DELTA;
398    uint32_t grid32[2]; const int8_t * q = (const int8_t *)grid32;
399    grid32[0] = iq1s_grid_gpu[x[ibs].qs[4*ib+il] | (((x[ibs].qh[2*ib+il/2] >> 4*(il%2)) & 7) << 8)];
400    grid32[1] = (grid32[0] >> 4) & 0x0f0f0f0f;
401    grid32[0] &= 0x0f0f0f0f;
402    for (int j = 0; j < 8; ++j) {
403        y[j] = ggml_cuda_cast<dst_t>(d * (q[j] + delta));
404    }
405}
406
407template<typename dst_t>
408static __device__ __forceinline__ void dequantize_iq4_nl(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
409
410    const block_iq4_nl * x = (const block_iq4_nl *) vx + ibs*(QK_K/QK4_NL);
411
412    const int64_t il = tid/8; // 0...3
413    const int64_t ib = tid%8; // 0...7
414    dst_t * y = yy + 32*ib + 4*il;
415    const uint8_t  * q4 = x[ib].qs + 4*il;
416    const float d = (float)x[ib].d;
417    for (int j = 0; j < 4; ++j) {
418        y[j+ 0] = ggml_cuda_cast<dst_t>(d * kvalues_iq4nl[q4[j] & 0xf]);
419        y[j+16] = ggml_cuda_cast<dst_t>(d * kvalues_iq4nl[q4[j] >>  4]);
420    }
421}
422
423template<typename dst_t>
424static __device__ __forceinline__ void dequantize_iq4_xs(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
425    const block_iq4_xs * x = (const block_iq4_xs *)vx;
426
427    const int64_t il = tid/8; // 0...3
428    const int64_t ib = tid%8; // 0...7
429    dst_t * y = yy + 32*ib + 4*il;
430    const uint8_t  * q4 = x[ibs].qs + 16*ib + 4*il;
431    const float d = (float)x[ibs].d * ((((x[ibs].scales_l[ib/2] >> 4*(ib%2)) & 0xf) | (((x[ibs].scales_h >> 2*ib) & 3) << 4)) - 32);
432    for (int j = 0; j < 4; ++j) {
433        y[j+ 0] = ggml_cuda_cast<dst_t>(d * kvalues_iq4nl[q4[j] & 0xf]);
434        y[j+16] = ggml_cuda_cast<dst_t>(d * kvalues_iq4nl[q4[j] >>  4]);
435    }
436}
437
438template<typename dst_t>
439static __device__ __forceinline__ void dequantize_mxfp4(const void * vx, const int64_t ibs, dst_t * yy, const int tid) {
440
441    const block_mxfp4 * x = (const block_mxfp4 *) vx + ibs*(QK_K/QK_MXFP4);
442
443    const int64_t il = tid/8; // 0...3
444    const int64_t ib = tid%8; // 0...7
445    dst_t * y = yy + 32*ib + 4*il;
446    const uint8_t  * q4 = x[ib].qs + 4*il;
447    const float d = ggml_cuda_e8m0_to_fp32(x[ib].e);
448    for (int j = 0; j < 4; ++j) {
449        y[j+ 0] = ggml_cuda_cast<dst_t>(d * kvalues_mxfp4[q4[j] & 0xf]*0.5f);
450        y[j+16] = ggml_cuda_cast<dst_t>(d * kvalues_mxfp4[q4[j] >>  4]*0.5f);
451    }
452}