#ifdef Q_F32
#define Q_TYPE f32
#else
#define Q_TYPE f16
#endif
#ifdef K_F32
#define K_TYPE f32
#elif defined(K_Q4_0) || defined(K_Q8_0)
#define K_TYPE u32
#else
#define K_TYPE f16
#endif
#ifdef V_F32
#define V_TYPE f32
#elif defined(V_Q4_0) || defined(V_Q8_0)
#define V_TYPE u32
#else
#define V_TYPE f16
#endif
#ifdef DST_F32
#define DST_TYPE f32
#else
#define DST_TYPE f16
#endif
#if defined(FLASH_ATTN_SCALAR_KV) || defined(K_Q4_0) || defined(K_Q8_0)
#define K_STORAGE_TYPE K_TYPE
#else
#define K_STORAGE_TYPE vec4<K_TYPE>
#endif
#if defined(FLASH_ATTN_SCALAR_KV) || defined(V_Q4_0) || defined(V_Q8_0)
#define V_STORAGE_TYPE V_TYPE
#else
#define V_STORAGE_TYPE vec4<V_TYPE>
#endif
// Just a very small float value.
const FLOAT_MIN: f32 = -1.0e9;
struct Params {
offset_q: u32,
offset_k: u32,
offset_v: u32,
offset_mask: u32,
offset_sinks: u32,
offset_dst: u32,
// shapes of Q/K/V
n_heads: u32,
seq_len_q: u32,
seq_len_kv: u32,
// strides (in elements)
stride_q1: u32,
stride_q2: u32,
stride_q3: u32,
stride_k1: u32,
stride_k2: u32,
stride_k3: u32,
stride_v1: u32,
stride_v2: u32,
stride_v3: u32,
stride_mask3: u32,
// repeat factors for K/V, e.g., MHA vs. MQA vs. GQA
q_per_kv: u32,
// softmax params
scale: f32,
max_bias: f32,
logit_softcap: f32,
n_head_log2: f32,
m0: f32,
m1: f32,
#ifdef FLASH_ATTN_VEC_SPLIT
#ifdef BLK
blk_base: u32,
blk_nblk0: u32,
blk_nblk1: u32,
#endif
tmp_data_base: u32,
tmp_stats_base: u32,
nwg: u32,
#endif
};
@group(0) @binding(0) var<storage, read_write> Q: array<Q_TYPE>;
@group(0) @binding(1) var<storage, read_write> K: array<K_STORAGE_TYPE>;
#ifdef KV_OVERLAP
#define V K
#define MASK_BINDING 2
#else
@group(0) @binding(2) var<storage, read_write> V: array<V_STORAGE_TYPE>;
#define MASK_BINDING 3
#endif // KV_OVERLAP
#ifdef MASK
@group(0) @binding(MASK_BINDING) var<storage, read_write> mask: array<f16>;
#define SINKS_BINDING (MASK_BINDING + 1)
#else
#define SINKS_BINDING MASK_BINDING
#endif
#ifdef SINKS
@group(0) @binding(SINKS_BINDING) var<storage, read_write> sinks: array<f32>;
#define BLK_BINDING (SINKS_BINDING + 1)
#else
#define BLK_BINDING SINKS_BINDING
#endif
#ifdef FLASH_ATTN_VEC_SPLIT
#ifdef BLK
@group(0) @binding(BLK_BINDING) var<storage, read_write> blk: array<u32>;
#define TMP_BINDING (BLK_BINDING + 1)
#else
#define TMP_BINDING BLK_BINDING
#endif
@group(0) @binding(TMP_BINDING) var<storage, read_write> tmp: array<f32>;
#define DST_BINDING (TMP_BINDING + 1)
#else
#define DST_BINDING BLK_BINDING
#endif // FLASH_ATTN_VEC_SPLIT
@group(0) @binding(DST_BINDING) var<storage, read_write> dst: array<vec4<DST_TYPE>>;
#define PARAMS_BINDING (DST_BINDING + 1)
@group(0) @binding(PARAMS_BINDING) var<uniform> params: Params;