* Re: ADA-9x done? Any good PC compilers? [not found] <1995Jan11.154250@clstac> @ 1995-01-12 22:14 ` Robert Dewar 1995-01-13 14:02 ` Howard.Gilbert 0 siblings, 1 reply; 5+ messages in thread From: Robert Dewar @ 1995-01-12 22:14 UTC (permalink / raw) You asked for Ada on a PC platform, so it is worth pointing out that the OS/2 version of GNAT on the PC does support tasking. P.S. the delay bug is fixed in the latest development version people will be glad to hear! Actually it was not technically a bug, since compilers are allowed to take longer than the minimum for a delay, if you had waited 25,000 years, the delay would have expired :-) :-) ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ADA-9x done? Any good PC compilers? 1995-01-12 22:14 ` ADA-9x done? Any good PC compilers? Robert Dewar @ 1995-01-13 14:02 ` Howard.Gilbert [not found] ` <3f9m5u$rc8@gnat.cs.nyu.edu> 0 siblings, 1 reply; 5+ messages in thread From: Howard.Gilbert @ 1995-01-13 14:02 UTC (permalink / raw) In <3f49k3$kfp@gnat.cs.nyu.edu>, dewar@cs.nyu.edu (Robert Dewar) writes: > >Actually it was not technically a bug, since compilers are allowed to >take longer than the minimum for a delay, if you had waited 25,000 years, >the delay would have expired :-) :-) Now you are beginning to sound like Microsoft. ^ permalink raw reply [flat|nested] 5+ messages in thread
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* Re: ADA-9x done? Any good PC compilers? [not found] ` <EACHUS.95Jan17120531@spectre.mitre.org> @ 1995-01-18 23:17 ` Robert Dewar 1995-01-19 19:08 ` Robert I. Eachus 0 siblings, 1 reply; 5+ messages in thread From: Robert Dewar @ 1995-01-18 23:17 UTC (permalink / raw) I was talking about when a delay expires, this has nothing to do with the required preemption by a higher priority task! (responding to Eachus' note on my note about infinite delays) ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ADA-9x done? Any good PC compilers? 1995-01-18 23:17 ` Robert Dewar @ 1995-01-19 19:08 ` Robert I. Eachus 1995-01-21 5:31 ` Robert Dewar 0 siblings, 1 reply; 5+ messages in thread From: Robert I. Eachus @ 1995-01-19 19:08 UTC (permalink / raw) In article <3fk7j7$ld5@gnat.cs.nyu.edu> dewar@cs.nyu.edu (Robert Dewar) writes: > I was talking about when a delay expires, this has nothing to do with the > required preemption by a higher priority task! > (responding to Eachus' note on my note about infinite delays) RM83 9.6(1): The execution of a delay statement evaluates the simple expression, and suspends further execution...for at least the duration specified by the resulting value. RM83 9.8(4): If two tasks with different priorities are both eligible for execution...then it cannot be the case that the task with the lower priority is executing while the task with the higher priority is not. The first creates a requirement that the delay must be at least that specified in the expression, the second paragraph adds a requirement which, on a single processor system, simplifies to: "The highest priority eligible task must be executing, in case of ties, the selection among the tied set is implemetation dependent." Paragraph 9.6(1) does not conflict with or supercede 9.8(4). They work together. Paragraph 9.6(1) declares certain tasks ineligible until the delay expires, 9.8(4) specifies requirements with respect to eligible tasks. I think you (Robert) perfectly well understand that the only freedom granted by 9.6 with respect to 9.8 is that the clock for interrupts need not be maintained to DURATION'SMALL resolution. The resolution is found instead in SYSTEM.TICK. If you want to validate a system where SYSTEM.TICK = DURATION'LAST, fine. But that still won't allow infinite prolongation of delays. -- Robert I. Eachus with Standard_Disclaimer; use Standard_Disclaimer; function Message (Text: in Clever_Ideas) return Better_Ideas is... ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ADA-9x done? Any good PC compilers? 1995-01-19 19:08 ` Robert I. Eachus @ 1995-01-21 5:31 ` Robert Dewar 0 siblings, 0 replies; 5+ messages in thread From: Robert Dewar @ 1995-01-21 5:31 UTC (permalink / raw) Robert Eachus is wrong in thinking System.Tick has anything to do with delays in Ada 83 (I guess he missed the ARG meeting where we discussed this :-) ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~1995-01-21 5:31 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <1995Jan11.154250@clstac> 1995-01-12 22:14 ` ADA-9x done? Any good PC compilers? Robert Dewar 1995-01-13 14:02 ` Howard.Gilbert [not found] ` <3f9m5u$rc8@gnat.cs.nyu.edu> [not found] ` <EACHUS.95Jan17120531@spectre.mitre.org> 1995-01-18 23:17 ` Robert Dewar 1995-01-19 19:08 ` Robert I. Eachus 1995-01-21 5:31 ` Robert Dewar
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