hamer-p150 / code /hamer /kernels /eltwise /reader.cpp
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Optimized build (2026-10-03): model call 3.49 ms, device 3.36 ms
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// SPDX-FileCopyrightText: © 2026 Tenstorrent Inc.
// SPDX-License-Identifier: Apache-2.0
// Unary eltwise reader: pages [start, start+n) of the source (interleaved or sharded) into cb 0 in one
// batch (the CB holds the core's whole range). compile-time: TensorAccessorArgs(src).
// runtime: src_addr, start, n [, npf, w_addr, npf x (bank, bank offset, local dst, bytes)]
// npf > 0 (cross-op weight prefetch, tt_kernels.gelu(prefetch=...)): after its own tiles this core reads
// npf contiguous DRAM blocks (the next cmm_linear's first weight blocks) into a persistent L1 buffer
// (plain reads + one plain barrier before the kernel ends, so the data is in L1 when the next op starts)
#include <stdint.h>
#include "api/dataflow/dataflow_api.h"
void kernel_main() {
const uint32_t src_addr = get_arg_val<uint32_t>(0);
const uint32_t start = get_arg_val<uint32_t>(1);
const uint32_t n = get_arg_val<uint32_t>(2);
constexpr auto src_args = TensorAccessorArgs<0>();
constexpr uint32_t cb = 0;
const uint32_t page = get_local_cb_interface(cb).fifo_page_size;
const auto src = TensorAccessor(src_args, src_addr, page);
// in up to 4 chunks so the compute starts on the first tiles while the rest are in flight
cb_reserve_back(cb, n);
uint32_t dst = get_write_ptr(cb);
const uint32_t chunk = (n + 7) / 8;
for (uint32_t j0 = 0; j0 < n; j0 += chunk) {
const uint32_t m = (n - j0) < chunk ? (n - j0) : chunk;
for (uint32_t j = 0; j < m; ++j) {
noc_async_read(src.get_noc_addr(start + j0 + j), dst, page);
dst += page;
}
noc_async_read_barrier();
cb_push_back(cb, m);
}
#ifdef ELT_PREFETCH
const uint32_t npf = get_arg_val<uint32_t>(3);
if (npf) {
const uint32_t w_addr = get_arg_val<uint32_t>(4);
for (uint32_t i = 0; i < npf; ++i) {
const uint32_t bank = get_arg_val<uint32_t>(5 + 4 * i), off = get_arg_val<uint32_t>(6 + 4 * i);
const uint32_t ldst = get_arg_val<uint32_t>(7 + 4 * i), bytes = get_arg_val<uint32_t>(8 + 4 * i);
noc_async_read(get_noc_addr_from_bank_id<true>(bank, w_addr + off), ldst, bytes);
}
noc_async_read_barrier();
}
#endif
}