zephyr/arch/arc/core/atomic.S
Daniel Leung db2d48b66f arc: add atomic operations for ARC EM family processors
The ARC EM family processors do not support native atomic assembly
instructions (LLOCK and SCOND). Therefore, the assembly version
of atomic functions cannot be used. This adds pure C version of
these atomic functions.

Change-Id: Ic64dd31b0367b6dcf3a46f41c0c7ac2c2ce5eb8d
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2016-02-05 20:25:16 -05:00

435 lines
11 KiB
ArmAsm

/*
* Copyright (c) 2014 Wind River Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* @brief ARC atomic operations library
*
* This library provides routines to perform a number of atomic operations
* on a memory location: add, subtract, increment, decrement, bitwise OR,
* bitwise NOR, bitwise AND, bitwise NAND, set, clear and compare-and-swap.
*
* This requires the processor to support LLOCK and SCOND instructions,
* where they are not supported on ARC EM family processors.
*/
#define _ASMLANGUAGE
#include <toolchain.h>
#include <sections.h>
/* exports */
GTEXT(atomic_set)
GTEXT(atomic_get)
GTEXT(atomic_add)
GTEXT(atomic_nand)
GTEXT(atomic_and)
GTEXT(atomic_or)
GTEXT(atomic_xor)
GTEXT(atomic_clear)
GTEXT(atomic_dec)
GTEXT(atomic_inc)
GTEXT(atomic_sub)
GTEXT(atomic_cas)
.section .TEXT._Atomic, "ax"
.balign 2
/**
*
* @brief Atomically clear a memory location
*
* This routine atomically clears the contents of <target> and returns the old
* value that was in <target>.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_clear
* (
* atomic_t *target /@ memory location to clear @/
* )
*/
SECTION_SUBSEC_FUNC(TEXT, atomic_clear_set, atomic_clear)
mov_s r1, 0
/* fall through into atomic_set */
/**
*
* @brief Atomically set a memory location
*
* This routine atomically sets the contents of <target> to <value> and returns
* the old value that was in <target>.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_set
* (
* atomic_t *target, /@ memory location to set @/
* atomic_val_t value /@ set with this value @/
* )
*
*/
SECTION_SUBSEC_FUNC(TEXT, atomic_clear_set, atomic_set)
ex r1, [r0] /* swap new value with old value */
j_s.d [blink]
mov_s r0, r1 /* return old value */
/**
*
* @brief Get the value of a shared memory atomically
*
* This routine atomically retrieves the value in *target
*
* atomic_val_t atomic_get
* (
* atomic_t *target /@ address of atom to be retrieved @/
* )
*
* RETURN: value read from address target.
*
*/
SECTION_FUNC(TEXT, atomic_get)
ld_s r0, [r0, 0]
j_s [blink]
/**
*
* @brief Atomically increment a memory location
*
* This routine atomically increments the value in <target>. The operation is
* done using unsigned integer arithmetic. Various CPU architectures may impose
* restrictions with regards to the alignment and cache attributes of the
* atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_inc
* (
* atomic_t *target, /@ memory location to increment @/
* )
*
*/
SECTION_SUBSEC_FUNC(TEXT, atomic_inc_add, atomic_inc)
mov_s r1, 1
/* fall through into atomic_add */
/**
*
* @brief Atomically add a value to a memory location
*
* This routine atomically adds the contents of <target> and <value>, placing
* the result in <target>. The operation is done using signed integer arithmetic.
* Various CPU architectures may impose restrictions with regards to the
* alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_add
* (
* atomic_t *target, /@ memory location to add to @/
* atomic_val_t value /@ value to add @/
* )
*/
SECTION_SUBSEC_FUNC(TEXT, atomic_inc_add, atomic_add)
llock r2, [r0] /* load old value and mark exclusive access */
add_s r3, r1, r2
scond r3, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_add /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, r2 /* return old value */
/**
*
* @brief Atomically decrement a memory location
*
* This routine atomically decrements the value in <target>. The operation is
* done using unsigned integer arithmetic. Various CPU architectures may impose
* restrictions with regards to the alignment and cache attributes of the
* atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_dec
* (
* atomic_t *target, /@ memory location to decrement @/
* )
*
*/
SECTION_SUBSEC_FUNC(TEXT, atomic_dec_sub, atomic_dec)
mov_s r1, 1
/* fall through into atomic_sub */
/**
*
* @brief Atomically subtract a value from a memory location
*
* This routine atomically subtracts <value> from the contents of <target>,
* placing the result in <target>. The operation is done using signed integer
* arithmetic. Various CPU architectures may impose restrictions with regards to
* the alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_sub
* (
* atomic_t *target, /@ memory location to subtract from @/
* atomic_val_t value /@ value to subtract @/
* )
*
*/
SECTION_SUBSEC_FUNC(TEXT, atomic_dec_sub, atomic_sub)
llock r2, [r0] /* load old value and mark exclusive access */
sub r3, r2, r1
scond r3, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_sub /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, r2 /* return old value */
/**
*
* @brief Atomically perform a bitwise NAND on a memory location
*
* This routine atomically performs a bitwise NAND operation of the contents of
* <target> and <value>, placing the result in <target>.
* Various CPU architectures may impose restrictions with regards to the
* alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_nand
* (
* atomic_t *target, /@ memory location to NAND @/
* atomic_val_t value /@ NAND with this value @/
* )
*
*/
SECTION_FUNC(TEXT, atomic_nand)
llock r2, [r0] /* load old value and mark exclusive access */
and r3, r1, r2
not r3, r3
scond r3, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_nand /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, r2 /* return old value */
/**
*
* @brief Atomically perform a bitwise AND on a memory location
*
* This routine atomically performs a bitwise AND operation of the contents of
* <target> and <value>, placing the result in <target>.
* Various CPU architectures may impose restrictions with regards to the
* alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_and
* (
* atomic_t *target, /@ memory location to AND @/
* atomic_val_t value /@ AND with this value @/
* )
*
*/
SECTION_FUNC(TEXT, atomic_and)
llock r2, [r0] /* load old value and mark exclusive access */
and r3, r1, r2
scond r3, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_and /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, r2 /* return old value */
/**
*
* @brief Atomically perform a bitwise OR on memory location
*
* This routine atomically performs a bitwise OR operation of the contents of
* <target> and <value>, placing the result in <target>.
* Various CPU architectures may impose restrictions with regards to the
* alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_or
* (
* atomic_t *target, /@ memory location to OR @/
* atomic_val_t value /@ OR with this value @/
* )
*
*/
SECTION_FUNC(TEXT, atomic_or)
llock r2, [r0] /* load old value and mark exclusive access */
or r3, r1, r2
scond r3, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_or /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, r2 /* return old value */
/**
*
* @brief Atomically perform a bitwise XOR on a memory location
*
* This routine atomically performs a bitwise XOR operation of the contents of
* <target> and <value>, placing the result in <target>.
* Various CPU architectures may impose restrictions with regards to the
* alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return Contents of <target> before the atomic operation
*
* ERRNO: N/A
*
* atomic_val_t atomic_xor
* (
* atomic_t *target, /@ memory location to XOR @/
* atomic_val_t value /@ XOR with this value @/
* )
*
*/
SECTION_FUNC(TEXT, atomic_xor)
llock r2, [r0] /* load old value and mark exclusive access */
xor r3, r1, r2
scond r3, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_xor /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, r2 /* return old value */
/**
*
* @brief Atomically compare-and-swap the contents of a memory location
*
* This routine performs an atomic compare-and-swap. testing that the contents of
* <target> contains <oldValue>, and if it does, setting the value of <target>
* to <newValue>. Various CPU architectures may impose restrictions with regards
* to the alignment and cache attributes of the atomic_t type.
*
* This routine can be used from both task and interrupt level.
*
* @return 1 if the swap is actually executed, 0 otherwise.
*
* ERRNO: N/A
*
* int atomic_cas
* (
* atomic_t *target, /@ memory location to compare-and-swap @/
* atomic_val_t oldValue, /@ compare to this value @/
* atomic_val_t newValue, /@ swap with this value @/
* )
*
*/
SECTION_FUNC(TEXT, atomic_cas)
llock r3, [r0] /* load old value and mark exclusive access */
cmp_s r1, r3
bne_s nanoAtomicCas_fail
scond r2, [r0] /* try to store new value */
/* STATUS32.Z = 1 if successful */
bne_s atomic_cas /* if store is not successful, retry */
j_s.d [blink]
mov_s r0, 1 /* return TRUE */
/* failed comparison */
nanoAtomicCas_fail:
scond r1, [r0] /* write old value to clear the access lock */
j_s.d [blink]
mov_s r0, 0 /* return FALSE */