os9@cbosgd.att.com (01/07/87)
OS-9 Discussions Wednesday, January 7th 1987 Volume 2 : Issue 9 Today's Topics: stack usage in device drivers -------------------------------------------------------------------------- Date: 6 Jan 1987 1345-CST (Tuesday) From: sun!mcrware!jejones (James Jones) Subject: stack usage in device drivers [The following is a reply to a query about stack usage in device drivers. The author of the query, exunido!res (Ralf Stranzenbach), felt that the answer would be of general interest, so I forward it to mod.os.os9 as well as to him...James Jones] ------- Forwarded Message In system state OS-9/68k only reserves about 2K of stack. Everything in the kernel, FMs, etc. are very stack conservative. Just a few temps, register saves and return addresses appear there. If a driver intends to use a lot of stack, you should consider whether the stack should really be used. Normally, driver code is not recursively or indirectly re-entered so there is really no need to keep massive stuff on the stack. Remember that if the driver sleeps with a big hunk of stack swallowed, that could be asking for trouble. My rule of thumb is to reserve the space in driver static storage if the amount is under 1K. If the data is over 1K or large or transient in nature, do an F$SrqMem to request the memory from the system. This should eliminate any question of stack overusage. ------- End of Forwarded Message ------------------------------------- The views expressed in OS-9 Discussions are those of the individual authors only. ------ Moderator: John Daleske cbosgd!cbdkc1!daleske daleske@cbdkc1.ATT.COM Submissions should go to cbosgd!os9 os9@cbosgd.ATT.COM Comments to the moderator or to join the mailing cbosgd!os9-request os9-request@cbosgd.ATT.COM list. ********************* End of OS-9 Discussions *********************