mirror of
https://gitlab.com/sortix/sortix.git
synced 2023-02-13 20:55:38 -05:00
57 lines
1.8 KiB
ArmAsm
57 lines
1.8 KiB
ArmAsm
|
/*******************************************************************************
|
||
|
|
|
||
|
|
Copyright(C) Jonas 'Sortie' Termansen 2012.
|
||
|
|
|
||
|
|
This file is part of Sortix.
|
||
|
|
|
||
|
|
Sortix is free software: you can redistribute it and/or modify it under the
|
||
|
|
terms of the GNU General Public License as published by the Free Software
|
||
|
|
Foundation, either version 3 of the License, or (at your option) any later
|
||
|
|
version.
|
||
|
|
|
||
|
|
Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
|
||
|
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
||
|
|
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
|
||
|
|
details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public License along with
|
||
|
|
Sortix. If not, see <http://www.gnu.org/licenses/>.
|
||
|
|
|
||
|
|
x64/interlock.s
|
||
|
|
Functions that perform non-atomic operations in an atomic manner.
|
||
|
|
|
||
|
|
*******************************************************************************/
|
||
|
|
|
||
|
|
.section .text
|
||
|
|
|
||
|
|
# Atomicly runs a function on a value and returns the unmodified value.
|
||
|
|
# ilret_t
|
||
|
|
# asm_interlocked_modify(unsigned long* val,
|
||
|
|
# unsigned long (*func)(unsigned long, unsigned long),
|
||
|
|
# unsigned long user);
|
||
|
|
.global asm_interlocked_modify
|
||
|
|
.type asm_interlocked_modify, @function
|
||
|
|
asm_interlocked_modify:
|
||
|
|
pushq %rbp
|
||
|
|
movq %rsp, %rbp
|
||
|
|
asm_interlocked_modify_retry:
|
||
|
|
# Save our parameters in case we need to retry.
|
||
|
|
pushq %rdi
|
||
|
|
pushq %rsi
|
||
|
|
pushq %rdx
|
||
|
|
# Read the current value and calculate the replacement.
|
||
|
|
movq (%rdi), %rdi
|
||
|
|
movq %rdx, %rsi
|
||
|
|
callq *%rsi
|
||
|
|
movq %rax, %rdx
|
||
|
|
popq %rax
|
||
|
|
popq %rdi
|
||
|
|
popq %rsi
|
||
|
|
# Atomicly assign the replacement if the value is unchanged.
|
||
|
|
cmpxchgq %rdx, (%rdi)
|
||
|
|
# Retry if the value was modified by someone else.
|
||
|
|
jnz asm_interlocked_modify_retry
|
||
|
|
# Return the old value in %rax, new one in %rdx.
|
||
|
|
leaveq
|
||
|
|
retq
|