1#version 450
 2
 3#include "soft_max_large_common.glsl"
 4
 5void main() {
 6    const uint tid = gl_LocalInvocationID.x;
 7    const uint rowx = gl_WorkGroupID.y;
 8    const uint wg_start = gl_WorkGroupID.x * BLOCK_SIZE * num_iters;
 9
10    const uint32_t i03 = rowx / (p.ne01 * p.ne02);
11    const uint32_t i02 = (rowx - i03 * p.ne01 * p.ne02) / p.ne01;
12    const uint32_t i01 = rowx % p.ne01;
13
14    uint rowy_start = 0;
15    if (p.KY > 0) {
16        rowy_start = i01 * p.nb11 + (i02 % p.ne12) * p.nb12 + (i03 % p.ne13) * p.nb13;
17    }
18
19    if (rowx >= p.nrows_x) {
20        return;
21    }
22
23    float slope = get_slope(rowx);
24
25    // Find max
26    FLOAT_TYPE max_val = p.has_sinks == 0 ? uintBitsToFloat(0xFF800000) : data_c[i02];
27
28    [[unroll]] for (uint i = 0; i < gl_NumWorkGroups.x; i += BLOCK_SIZE) {
29        if (i + tid < gl_NumWorkGroups.x) {
30            max_val = max(max_val, data_m[rowx * gl_NumWorkGroups.x + i + tid]);
31        }
32    }
33
34    // reduce across the workgroup
35    vals[tid] = max_val;
36    barrier();
37    [[unroll]] for (uint s = BLOCK_SIZE / 2; s > 0; s >>= 1) {
38        if (tid < s) {
39            vals[tid] = max(max_val, vals[tid + s]);
40        }
41        barrier();
42    }
43
44    max_val = vals[0];
45    barrier();
46
47    FLOAT_TYPE sum = FLOAT_TYPE(0.0f);
48
49    // Compute sum{exp(x - max)}
50    [[unroll]] for (uint col0 = wg_start, idx = 0; idx < num_iters; col0 += BLOCK_SIZE, ++idx) {
51        const uint col = col0 + tid;
52
53        if (col >= p.KX) {
54            break;
55        }
56
57        // compute exp(a*scale+b*slope), add it to sum
58        const uint i = rowx * p.KX + col;
59        FLOAT_TYPE val;
60        val = exp(FLOAT_TYPE(data_a[i]) * p.scale + (p.KY > 0 ? slope * FLOAT_TYPE(data_b[rowy_start + col]) : FLOAT_TYPE(0.0f)) - max_val);
61        sum += val;
62        data_d[i] = D_TYPE(val);
63    }
64
65    // reduce across the workgroup
66    vals[tid] = sum;
67    barrier();
68    [[unroll]] for (uint s = BLOCK_SIZE / 2; s > 0; s >>= 1) {
69        if (tid < s) {
70            vals[tid] += vals[tid + s];
71        }
72        barrier();
73    }
74
75    if (tid == 0) {
76        sum = vals[0];
77        data_s[rowx * gl_NumWorkGroups.x + gl_WorkGroupID.x] = sum;
78    }
79}