Deep Note: agent/example/kernels/a2/flash_attn_full_pj_hif8.py

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Open this file only after the short catalog entry confirmed the kernel is relevant.

What this kernel is really for

• the scaled-hif8 probability variant of normalized a2 online softmax
• a contract that intentionally changes the delayed value path while keeping row_sum in float
• a kernel that exports final rowmax / rowsum as part of the visible contract

Decisions worth copying

• update row_sum from the float p_j tile before any half / hif8 cast
• keep stage-1 score scratch and stage-2 pv scratch separate in the readable baseline
• implement the non-negative hif8 simulation without relying on unsupported uint8 -> float shortcuts
• copy [M,64] score slices into contiguous scratch before reinterpret(...) when the quantized helper needs contiguous lanes
• handle non-aligned S2 in score space with suffix invalidation and a sufficiently negative finite sentinel
• handle non-aligned S1 separately from S2; invalid rows should become zero contribution to delayed p @ v while GM still writes only valid rows

Prefer another kernel when

• you still want the plain p.half().float() value path
• you are debugging the normalized float/half baseline before introducing hif8 behavior

【免费下载链接】cannbot-skills CANNBot 是面向 CANN 开发的用于提升开发效率的系列智能体，本仓库为其提供可复用的 Skills 模块。 项目地址: https://gitcode.com/cann/cannbot-skills