path: root/lib/system/systhread.nim

#
#
#            Nimrod's Runtime Library
#        (c) Copyright 2011 Andreas Rumpf
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

const
  hasThreadSupport = false # deactivate for now: thread stack walking
                           # is missing!
  maxThreads = 256

when (defined(gcc) or defined(llvm_gcc)) and hasThreadSupport:
  proc sync_add_and_fetch(p: var int, val: int): int {.
    importc: "__sync_add_and_fetch", nodecl.}
  proc sync_sub_and_fetch(p: var int, val: int): int {.
    importc: "__sync_sub_and_fetch", nodecl.}
elif defined(vcc) and hasThreadSupport:
  proc sync_add_and_fetch(p: var int, val: int): int {.
    importc: "NimXadd", nodecl.}
else:
  proc sync_add_and_fetch(p: var int, val: int): int {.inline.} =
    inc(p, val)
    result = p

var
  isMultiThreaded: bool # true when prog created at least 1 thread

proc atomicInc(memLoc: var int, x: int): int =
  when hasThreadSupport:
    result = sync_add_and_fetch(memLoc, x)
  else:
    inc(memLoc, x)
    result = memLoc
  
proc atomicDec(memLoc: var int, x: int): int =
  when hasThreadSupport:
    when defined(sync_sub_and_fetch):
      result = sync_sub_and_fetch(memLoc, x)
    else:
      result = sync_add_and_fetch(memLoc, -x)
  else:
    dec(memLoc, x)
    result = memLoc