sub_tiles

void ckernel::sub_init(uint32_t icb0, uint32_t icb1, bool acc_to_dest = false, uint32_t call_line = __builtin_LINE())

Paired init for two-operand element-wise subtraction (sub_tiles). Configures the unpacker and math pipeline so that SrcA <- icb0 and SrcB <- icb1. Call before sub_tiles. The one-time hardware configuration must already have been performed via compute_kernel_hw_startup(icb0, icb1, ocb) at the start of MAIN. For general information on init functions refer to any_init. For the dest-reuse variant (one operand from DST) use sub_reuse_dest_init<reuse_dest> below.

Argument	Description	Type	Valid Range	Required
icb0	CB whose tile is unpacked into SrcA (operand A)	uint32_t	0 to 31	True
icb1	CB whose tile is unpacked into SrcB (operand B)	uint32_t	0 to 31	True
acc_to_dest	If true, operation = A - B + dst_tile_idx of sub_tiles	bool	0,1	False

void ckernel::sub_tiles(uint32_t icb0, uint32_t icb1, uint32_t itile0, uint32_t itile1, uint32_t idst)

Performs element-wise subtraction C=A-B of tiles in two CBs at given indices and writes the result to the DST register at index dst_tile_index. The DST register buffer must be in acquired state via acquire_dst call. This call is blocking and is only available on the compute engine.

Return value: None

Argument	Description	Type	Valid Range	Required
icb0	The identifier of the circular buffer (CB) containing A	uint32_t	0 to 31	True
icb1	The identifier of the circular buffer (CB) containing B	uint32_t	0 to 31	True
itile0	The index of tile A within the first CB	uint32_t	Must be less than the size of the CB	True
itile1	The index of tile B within the second CB	uint32_t	Must be less than the size of the CB	True
idst	The index of the tile in DST REG for the result C	uint32_t	Must be less than the acquired size of DST REG	True

void ckernel::sub_block(uint32_t icb0, uint32_t icb1, uint32_t start_itile0, uint32_t start_itile1, uint32_t start_idst, uint32_t ntiles)

Performs element-wise subtraction C=A-B on ntiles consecutive tile pairs from two CBs, writing each result to a consecutive DST register slot. This is the uniform block entry point for the subtract op: its body is a simple loop over sub_tiles, so it inherits sub_tiles’s semantics and requires the same initialization (sub_init) to have been called first. The DST register buffer must be in acquired state via acquire_dst call. This call is blocking and is only available on the compute engine.

NOTE: The loop implementation is transitional. In the future this for-loop must be folded into a hardware MOP / REPLAY buffer (as is being done for Quasar) so the whole block issues as a single packed op; the blocking then lives in llk-lib without changing this signature. Tracked under the Compute API Split effort (tt-metal#35739); the per-op push-down lands in tt-metal#47482.

Return value: None

Argument	Description	Type	Valid Range	Required
icb0	The identifier of the circular buffer (CB) containing A	uint32_t	0 to 31	True
icb1	The identifier of the circular buffer (CB) containing B	uint32_t	0 to 31	True
start_itile0	The index of the first tile A within the first CB	uint32_t	Must be less than the size of the CB	True
start_itile1	The index of the first tile B within the second CB	uint32_t	Must be less than the size of the CB	True
start_idst	The index of the first tile in DST REG for the result C	uint32_t	Must be less than the acquired size of DST REG	True
ntiles	The number of consecutive tile pairs to subtract	uint32_t	start_idst + ntiles <= acquired DST REG size	True