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/*
* Copyright (c) 2018, Cornell University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of Cornell University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Tuan Ta
*/
//------------------------------------------------------------------------
// This code tests lr.d and sc.d instructions in multi-threading system.
// All threads execute a critical section LOOP_COUNT times. A thread
// gets into a critical section by acquiring a lock variable (i.e.,
// shared_var) and checking return value.
// 0 means the lock is not being locked. Each thread increments
// a variable (i.e., var) inside the critical section and releases the
// lock by swapping back 0 to the lock variable.
// The master thread (i.e., thread 0) waits for all threads to complete
// and compare the var's value to the expected result.
//------------------------------------------------------------------------
#include "riscv_test.h"
#include "test_macros.h"
#include "test_macros_mt.h"
RVTEST_RV64U
RVTEST_CODE_BEGIN
#define LOOP_COUNT 1000
#define RESULT NUM_THREADS * LOOP_COUNT
//------------------------------------------------------------------------
// Master thread creates new threads, waits for all threads to complete,
// deallocates threads and checks result
//------------------------------------------------------------------------
call _create_threads
call _join
call _delete_threads
call _check
RVTEST_CODE_END
//------------------------------------------------------------------------
// mt_test function executed in child threads
// A child thread signals its completion by atomicaly adding 1 to barrier
//------------------------------------------------------------------------
_mt_test:
li t0, 1 // initialize the swap value (1-locked)
li t1, LOOP_COUNT
la t2, var // load the var's address
la a0, shared_var
1:
lr.d.aq s2, (a0) // load and reserve a0
bnez s2, 1b // retry lr if the lock is being held
sc.d.rl s2, t0, (a0) // try to lock a0
bnez s2, 1b // retry if sc failed
lw t3, (t2) // load the var's value
addi t3, t3, 1 // add 1 to the value
sw t3, (t2) // store the new value to var
sd zero, (a0) // release the lock by storing 0 to a0
addi t1, t1, -1 // decrement the loop_count
bnez t1, 1b // repeat if not done yet
la a0, barrier
amoadd.d zero, t0, (a0) // signal this thread's completion
RVTEST_CODE_END
//------------------------------------------------------------------------
// Master thread checks result
//------------------------------------------------------------------------
_check:
la a0, var
li a1, RESULT
ld a0, (a0)
bne a0, a1, _fail
li a0, SUCCESS
ret
_fail:
li a0, FAILURE
ret
.data
MT_DATA
var: .dword 0
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