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/* SPDX-License-Identifier: MIT */
/*
* Copyright 2025 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
// This shader is to clean LDS, SGPRs and VGPRs. It is first 64 Dwords or 256 bytes of 256 Dwords cleaner shader.
// GFX10.1 : Clear SGPRs, VGPRs and LDS
// Launch 32 waves per CU (16 per SIMD) as a workgroup (threadgroup) to fill every wave slot
// Waves are "wave32" and have 64 VGPRs each, which uses all 1024 VGPRs per SIMD
// Waves are launched in "CU" mode, and the workgroup shares 64KB of LDS (half of the WGP's LDS)
// It takes 2 workgroups to use all of LDS: one on each CU of the WGP
// Each wave clears SGPRs 0 - 107
// Each wave clears VGPRs 0 - 63
// The first wave of the workgroup clears its 64KB of LDS
// The shader starts with "S_BARRIER" to ensure SPI has launched all waves of the workgroup
// before any wave in the workgroup could end. Without this, it is possible not all SGPRs get cleared.
shader main
asic(GFX10.1)
type(CS)
wave_size(32)
// Note: original source code from SQ team
//
// Create 32 waves in a threadgroup (CS waves)
// Each allocates 64 VGPRs
// The workgroup allocates all of LDS (64kbytes)
//
// Takes about 2500 clocks to run.
// (theorhetical fastest = 1024clks vgpr + 640lds = 1660 clks)
//
S_BARRIER
s_cmp_eq_u32 s0, 1 // Bit0 is set, sgpr0 is set then clear VGPRS and LDS as FW set COMPUTE_USER_DATA_0
s_cbranch_scc0 label_0023 // Clean VGPRs and LDS if sgpr0 of wave is set, scc = (s0 == 1)
s_mov_b32 s2, 0x00000038 // Loop 64/8=8 times (loop unrolled for performance)
s_mov_b32 m0, 0
//
// CLEAR VGPRs
//
label_0005:
v_movreld_b32 v0, 0
v_movreld_b32 v1, 0
v_movreld_b32 v2, 0
v_movreld_b32 v3, 0
v_movreld_b32 v4, 0
v_movreld_b32 v5, 0
v_movreld_b32 v6, 0
v_movreld_b32 v7, 0
s_mov_b32 m0, s2
s_sub_u32 s2, s2, 8
s_cbranch_scc0 label_0005
//
s_mov_b32 s2, 0x80000000 // Bit31 is first_wave
s_and_b32 s2, s2, s0 // sgpr0 has tg_size (first_wave) term as in ucode only COMPUTE_PGM_RSRC2.tg_size_en is set
s_cbranch_scc0 label_0023 // Clean LDS if its first wave of ThreadGroup/WorkGroup
// CLEAR LDS
//
s_mov_b32 exec_lo, 0xffffffff
s_mov_b32 exec_hi, 0xffffffff
v_mbcnt_lo_u32_b32 v1, exec_hi, 0 // Set V1 to thread-ID (0..63)
v_mbcnt_hi_u32_b32 v1, exec_lo, v1 // Set V1 to thread-ID (0..63)
v_mul_u32_u24 v1, 0x00000008, v1 // * 8, so each thread is a double-dword address (8byte)
s_mov_b32 s2, 0x00000003f // 64 loop iterations
s_mov_b32 m0, 0xffffffff
// Clear all of LDS space
// Each FirstWave of WorkGroup clears 64kbyte block
label_001F:
ds_write2_b64 v1, v[2:3], v[2:3] offset1:32
ds_write2_b64 v1, v[4:5], v[4:5] offset0:64 offset1:96
v_add_co_u32 v1, vcc, 0x00000400, v1
s_sub_u32 s2, s2, 1
s_cbranch_scc0 label_001F
//
// CLEAR SGPRs
//
label_0023:
s_mov_b32 m0, 0x00000068 // Loop 108/4=27 times (loop unrolled for performance)
label_sgpr_loop:
s_movreld_b32 s0, 0
s_movreld_b32 s1, 0
s_movreld_b32 s2, 0
s_movreld_b32 s3, 0
s_sub_u32 m0, m0, 4
s_cbranch_scc0 label_sgpr_loop
//clear vcc
s_mov_b64 vcc, 0 //clear vcc
//s_setreg_imm32_b32 hw_reg_shader_flat_scratch_lo, 0 //clear flat scratch lo SGPR
//s_setreg_imm32_b32 hw_reg_shader_flat_scratch_hi, 0 //clear flat scratch hi SGPR
s_mov_b64 ttmp0, 0 //Clear ttmp0 and ttmp1
s_mov_b64 ttmp2, 0 //Clear ttmp2 and ttmp3
s_mov_b64 ttmp4, 0 //Clear ttmp4 and ttmp5
s_mov_b64 ttmp6, 0 //Clear ttmp6 and ttmp7
s_mov_b64 ttmp8, 0 //Clear ttmp8 and ttmp9
s_mov_b64 ttmp10, 0 //Clear ttmp10 and ttmp11
s_mov_b64 ttmp12, 0 //Clear ttmp12 and ttmp13
s_mov_b64 ttmp14, 0 //Clear ttmp14 and ttmp15
s_endpgm
end
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