asm

func SPSCDequeue ¶

func SPSCDequeue(q uintptr) (elem uintptr, err int)

SPSCDequeue performs an optimized SPSC dequeue operation. Combines cached index check, buffer load, and head update.

Returns:

• elem: the dequeued value (valid only if err == 0)
• err: 0 on success, 1 if queue is empty (ErrWouldBlock)

func SPSCEnqueue ¶

func SPSCEnqueue(q uintptr, elem uintptr) int

SPSCEnqueue performs an optimized SPSC enqueue operation. It combines the cached index check, buffer store, and tail update in a tight instruction sequence without Go runtime preemption points.

Parameters (passed via registers per Go ABI):

• q: pointer to SPSCIndirect struct
• elem: the uintptr value to enqueue

Returns:

• 0 on success
• 1 if queue is full (ErrWouldBlock)

The struct layout is (verified via reflection):

• offset 0: pad (64 bytes cache line isolation)
• offset 64: head (atomix.Uint64 - 8 bytes)
• offset 72: pad (64 bytes)
• offset 136: cachedTail (8 bytes, non-atomic)
• offset 144: pad (64 bytes)
• offset 208: tail (atomix.Uint64 - 8 bytes)
• offset 216: pad (64 bytes)
• offset 280: cachedHead (8 bytes, non-atomic)
• offset 288: pad (64 bytes)
• offset 352: buffer (slice header: ptr, len, cap = 24 bytes)
• offset 376: mask (8 bytes)
• Total size: 384 bytes