Macintosh-SW
/
sys7.1-doc-wip
mirror of https://github.com/elliotnunn/sys7.1-doc-wip.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
sys7.1-doc-wip/OS/TimeMgr/TimeMgr.a

1043 lines
41 KiB
Plaintext
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;
; Hacks to match MacOS (most recent first):
;
; <Sys7.1> 8/3/92 Removed <3> QuickTime patch code, and what looks like a total rewrite of
; __MicroSeconds.
; 9/2/94 SuperMario ROM source dump (header preserved below)
;
;
; File: TimeMgr.a
;
; Contains: The Macintosh OS Time Manager
;
; Written by: Gary G. Davidian
;
; Copyright: © 1988-1993 by Apple Computer, Inc., all rights reserved.
;
; Change History (most recent first):
;
; <SM5> 11/9/93 KW added some eieioSTP macros. Only expands for CygnusX1 ROM
; <SM4> 11/12/92 PN Get rid of ≥ 020 conditionals for ROM builds
; <3> 9/10/92 AEK Roll in new _microseconds and PrimeTime fix from Quicktime
; code for _microseconds was already there, so just remove old one
; <2> 3/27/92 JSM Merge in Philip’s change: Export Labels for Patch roll-in.
; <1> • Pre-SuperMario comments follow •
; <9> 2/12/92 JSM Moved this file to TimeMgr folder, keeping all the old
; revisions.
; <8> 11/16/91 DTY Checked in Wayne Meretzky’s new version of __MicroSeconds,
; conditionalized for TheFuture.
; <7> 9/9/91 JSM Cleanup header.
; <6> 9/22/90 dba Break some routines into separate PROCs so they can be cut back
; in the linked patch version. Also change conditionals so the the
; linked patch version of the Time Mgr. is universal (does not
; assume 68020 or existence of the Power Mgr. chip). This file is
; now used as the source both of the Time Mgr. in ROM and of the
; Time Mgr. patches.
; <5> 9/19/90 BG Removed <3>. 040s are behaving more reliably now.
; <4> 7/25/90 GGD Added support for the _MicroSeconds trap which returns a 64 bit
; Microsecond counter which is usefull for timestamping and
; timing. Deleted some Eclipse NOPs which would not be assembled
; for 68040s
; <3> 6/20/90 CCH Added some NOPs for flaky 68040's.
; <2> 1/12/90 CCH Added include of “HardwarePrivateEqu.a”.
; <1.4> 11/13/89 MSH Pmgr equates now in record format.
; <1.3> 2/23/89 GGD Stored the underflow retry adjustment constant in RAM to allow
; better patching flexability. On systems with PowerManagers,
; switch into fast mode in FreezeTime, and restore mode in
; ThawTime, to reduce drift in the time critical section, and to
; prevent a potential loop in the underflow path.
; <1.2> 1/30/89 GGD Added new features for BigBang and the new ROMs. This includes
; support for extended time manager tasks, and improves accuracy
; and reduces drift even more.
; <1.1> 11/10/88 CCH Fixed Header.
; <1.0> 11/9/88 CCH Adding to EASE.
; <1.4> 10/16/88 GGD Changed resolution to 20µs with range of 1 day. Improved long
; term accuracy, and added initialization code to do runtime
; timings to make it processor speed independent. Coded around the
; bug in Rockwell VIA timers. Removed machine specific
; conditionals in favor of the "Cpu" equate. Improved conversion
; constants for better accuracy. Went back to having state in the
; system heap.
; <•1.3> 9/23/88 CCH Got rid of inc.sum.d and empty nFiles
; <1.2> 8/16/88 GGD Added InitTimeMgr initialization routine. Changed usage of
; TimeVars, is now head of active list, no state in SysHeap.
; <1.1> 8/5/88 GGD Completely re-written. Lots of bug fixes and new features.
; 7/26/88 GGD Completely re-wrote the Time Manager, replacing all of the code
; and comments from the old version. This version fixes numerous
; bugs, and adds several new features.
; <1.0> 2/10/88 BBM Adding file for the first time into EASE…
;
TITLE 'Time Manager - Macintosh Time Manager'
;_______________________________________________________________________
;
; Macintosh Time Manager.
;
; Written by Gary G. Davidian, July 26, 1988.
;
;_______________________________________________________________________
print off
load 'StandardEqu.d'
include 'HardwarePrivateEqu.a'
print on,nomdir
if forROM then
use68020Opcodes: equ 1
machine MC68020
else
use68020Opcodes: equ 0
machine MC68020 ; some 020 opcodes in stuff that is run-time determined
endif
; globals in system heap (same RECORD in TimeMgrPatch.a; move it to an equate file if you like)
TimeMgrPrivate record 0,increment ; time manager private storage
ActivePtr ds.l 1 ; pointer to soonest active request
TimerAdjust ds.b 1 ; number of VIA ticks used loading timer
TimerLowSave ds.b 1 ; low byte of VIA timer from last FreezeTime <4>
RetryAdjust ds.w 1 ; number of via ticks for underflow retry
CurrentTime ds.l 1 ; number of virtual ticks since boot
BackLog ds.l 1 ; number of virtual ticks of ready tasks
**** NOTE: The ordering of the following 4 fields must not change (FreezeTime Depends on it) <4>
HighUSecs ds.l 1 ; high 32 bits of microsecond count <4>
LowUSecs ds.l 1 ; low 32 bits of microsecond count <4>
FractUSecs ds.w 1 ; 16 bit fractional microsecond count <4>
CurTimeThresh ds.w 1 ; CurrentTime threshold for updating µsec count <4>
**** end of order dependent fields <4>
PrivateSize equ *-TimeMgrPrivate ; size of this record
endr
USecsInc equ $FFF2E035 ; 65522.8758µsec (16.16 fixed point) <4>
ThreshInc equ 3208 ; = 3208 internal ticks <4>
eject
;_______________________________________________________________________
;
; The time manager maintains a linked list of tasks that are waiting for
; their timer to run out. The list is ordered by expiration time, with
; ActivePtr pointing to the task with the earliest timeout. The tmCount
; field of the each task on the list contains the number of virtual ticks
; a task must wait after the task in front of it expires. For the task
; at the head of the list, this is the time to wait after the VIA timer
; expires.
; The TimerAdjust variable is used to account for the number of VIA ticks
; that go by while we are trying to load a new timer value. This is
; computed at runtime, so that it is processor speed independent.
;
;_______________________________________________________________________
;_______________________________________________________________________
;
; User visible changes since Inside Macintosh Vol. 4 was published.
;
; 1) tmCount field is a LONGINT, not an INTEGER (documentation error).
;
; 2) RmvTime, and PrimeTime now correctly return a result code (noErr)
; in register D0. Numerous other bugs that were not as visible have
; also been fixed.
;
; 3) Time can be represented in microseconds as well as milliseconds.
; Negative values represent negated microseconds. (Although microseconds
; can be specified, the actual resolution of the time manager is
; currently closer to 20 microseconds).
;
; 4) The high order bit of qType is now a flag to indicate that the
; task timer is active. Set by PrimeTime, cleared when time expires
; or RmvTime is called. Initialized cleared by InsTime.
;
; 5) tmAddr may be set to zero to indicate that no completion routine
; should be called. (The flag mentioned above may be used to determine
; if the time has expired).
;
; 6) The completion routine is now passed a pointer (in register A1) to
; the TMTask record associated with it. This makes it more usable
; under Multi-Finder.
;
; 7) When RmvTime is called on an active task, the tmCount field will
; be returned with the amount of remaining time that had not been
; used (in negative microseconds, or positive milliseconds). If
; the task had already expired, tmCount will contain zero. This
; allows the Time Manager to be used to compute elapsed times, which
; is useful for performance measurments.
;
; 8) In order to provide better resolution than 1 millisecond, the maximum
; delay time was reduced from about 24 days, to currently about 1 day.
; Larger delay times may still be specified to PrimeTime, but they will
; be converted to the largest possible time instead.
;
; 9) Support for Extended Time Manager Tasks has been added, _InsXTime is
; used to install them. The new field tmWakeUp is used by the TimeMgr
; to remember when a _PrimeTime is supposed to expire. When _PrimeTime
; is called, if tmWakeUp is non-zero, then the new wakeup time will be
; relative to the old tmWakeUp, instead of relative to the current time.
; This allows for drift free fixed frequency timing tasks, which is needed
; by the Sound Manager.
;
;_______________________________________________________________________
TITLE 'Time Manager - Equates'
TaskActiveBit equ 7 ; high bit of QType word is active flag
ExtendedTmTaskBit equ 6 ; indicates an extended TmTask record
T2IntBit equ 5 ; VIER/VIFR bit num for VIA Timer 2
;_______________________________________________________________________
;
; Representations of time in the Time Manager.
;
; Time is represented externally in two ways, both are stored in a longword,
; if the value is positive, it represents milliseconds, and if it is
; negative, it represents negated microseconds. This representation is used
; as the delay time input to PrimeTime, and as the unused remaining time
; output by RmvTime.
;
; The VIA1 Timer2 is the 16 bit hardware timer used by the time manager.
; On all current machines, it decrements at a rate of 783360 Hz, and
; generates an interrupt, and keeps counting, when it counts through zero.
; This provides resolution of 1.276 µsec, and a range of 83.660 msec.
;
; Internally the time manager represents time as a virtual unsigned 36 bit
; VIA timer, which gives a range of about 1 day. However, since we only
; have 32 bits to store time in, we drop the low 4 bits of the timer,
; which reduces the resolution by a factor of 16 to 20.425 µsec.
;
; Converting between the external and internal forms of time is done by
; multiplying by the proper fixed point constants, and shifting the binary
; point of the 64 bit result to get just the integer portion of the result.
; The computation of the 32 bit conversion constants requires 64 bit
; intermediate results, and unfortunatly the assembler only provides 32
; bit expression evaluation, so the proper constants were computed with
; a 64 bit hex caculator, and hard coded here (yuck!). These are not
; "Magic Numbers", the formula for computing them is provided, so that
; they may be re-computed if any of the parameters ever change.
;
;_______________________________________________________________________
TicksPerSec equ 783360 ; VIA Timer clock rate
TickScale equ 4 ; Internal time is VIA ticks >> TickScale
MsToIntFractBits equ 26 ; number of fraction bits in 64 bit result
*MsToInternal equ ((TicksPerSec<<(MsToIntFractBits-TickScale))\
+999)/1000
MsToInternal equ $C3D70A3E ; msec to internal time multiplier
UsToIntFractBits equ 32 ; number of fraction bits in 64 bit result
*UsToInternal equ ((TicksPerSec<<(UsToIntFractBits-TickScale))\
+999999)/1000000
UsToInternal equ $0C88A47F ; µsec to internal time multiplier
IntToMsFractBits equ 32 ; number of fraction bits in 64 bit result
*InternalToMs equ ((1000<<(IntToMsFractBits+TickScale))\
+TicksPerSec-1)/TicksPerSec
InternalToMs equ $053A8FE6 ; internal time to msec multiplier
IntToUsFractBits equ 27 ; number of fraction bits in 64 bit result
*InternalToUs equ ((1000000<<(IntToUsFractBits+TickScale))\
+TicksPerSec-1)/TicksPerSec
InternalToUs equ $A36610BC ; internal time to µsec multiplier
macro ; Macro for interfacing with the MultAndMerge routine.
Convert &Multiplier,&FractionBits
bsr.s MultAndMerge ; input/output is D0
dc.l &Multiplier ; conversion multiplier
if &eval(&FractionBits)=32 then
dc.l 0 ; merge mask (low 32 bits all fraction)
else
dc.l -1<<&FractionBits ; merge mask (some low bits not fraction)
rol.l #32-&FractionBits,d0 ; position result after merge
endif
endm
TITLE 'Time Manager - Remove Time Manager Task'
TimeMgr proc export
export __InsTime ; Install Time Manager Task
export __RmvTime ; Remove Time Manager Task
export __PrimeTime ; Initiate Time Manager Task Delay
import FreezeTime ; Stop timer
entry ThawTime ; Start timer (used by InitTimeMgr)
entry Timer2Int ; Interrupt handler (vector set up by InitTimeMgr)
with TimeMgrPrivate
;_______________________________________________________________________
;
; Routine: RmvTime
; Inputs: A0 - pointer to Time Manager Task to remove
; Outputs: D0 - error code (noErr)
; Destroys: none
; Calls: FreezeTime, ThawTime, MultAndMerge
; Called by: OsTrap dispatcher
;
; Function: Removes the specified Time Manager Task from the control
; of the Time Manager. If PrimeTime had been previously
; called for this task, and the time has not expired yet,
; the amount of unused time will be returned in the tmCount
; field. The unused time will be represented in negated
; microseconds, if it is not too large to fit within 32 bits
; otherwise it will be represented in positive milliseconds.
; Additionally, the TaskActiveBit of the QType field will
; be cleared to indicate that the timer task is no longer
; active.
;
;_______________________________________________________________________
export AfterFreezeTimeInRmvTime
__RmvTime ; a0-a2/d1-d2 saved by dispatcher
move.l d3,-(sp) ; save d3 also
jsr FreezeTime ; setup to manipulate time queue
AfterFreezeTimeInRmvTime
moveq.l #0,d2 ; D2 : total time remaining
lea ActivePtr-Qlink(a2),a1 ; A1 : previous := head
@SearchLoop move.l QLink(a1),d0 ; D0 : next := previous.QLink
beq.s @NotActive ; if end, not an active task
exg.l a1,d0 ; A1 : previous := next (save old previous)
move.l tmCount(a1),d1 ; get delay between previous and next
add.l d1,d2 ; add to total time remaining
cmpa.l a0,a1 ; is this the one to remove?
bne.s @SearchLoop ; loop until it is found
movea.l d0,a1 ; A1 : old previous
move.l QLink(a0),d0 ; get successor to removee
move.l d0,QLink(a1) ; previous points to successor
beq.s @Removed ; if no successor, don't adjust time
movea.l d0,a1 ; get pointer to successor
add.l d1,tmCount(a1) ; pass removees time to successor
@Removed move.l d2,d0 ; setup total time remaining in D0
@NotActive ; at this point D0 is total time remaining
sub.l BackLog(a2),d0 ; don't count the backlog
bhs.s @GotRemaining ; if still time remaining
moveq.l #0,d0 ; otherwise, all backlog, return zero time
@GotRemaining
bsr.w ThawTime ; done manipulating time queue
movea.l d0,a1 ; save a copy of internal time
convert InternalToUs,IntToUsFractBits ; convert internal to µsec
neg.l d0 ; µsecs are passed negated
bmi.s @ConvertDone ; if it fits we're done
move.l a1,d0 ; restore copy of internal time
convert InternalToMs,IntToMsFractBits ; convert internal to msec
@ConvertDone
move.l d0,tmCount(a0) ; return unused delay time
move.l (sp)+,d3 ; restore saved d3
moveq.l #0,d1 ; clear all of the flags
; (fall in) bra.s __InsTime ; mark task inactive, return with success
TITLE 'Time Manager - Install Time Manager Task'
;_______________________________________________________________________
;
; Routine: InsTime
; Inputs: A0 - pointer to Time Manager Task to install
; Outputs: D0 - error code (noErr)
; Destroys: none
; Calls: none
; Called by: OsTrap dispatcher, RmvTime (falls into)
;
; Function: Initializes the fields of a Time Manager Task, to indicate
; that it is inactive.
;
; NOTE: This routine is documented in Inside Machintosh Vol 4., and
; was used by the old Time Manager to install the task on the
; Time Manager queue. In this version of the Time Manager, the
; queue only contains active tasks, so installation is done by
; _PrimeTime now.
;
;_______________________________________________________________________
__InsTime ; a0-a2/d1-d2 saved by dispatcher
moveq.l #$1F,d0 ; mask to clear flag bits in QType
and.b QType(a0),d0 ; clear the flags
andi.w #$0600,d1 ; isolate 2 flag bits from trap word
lsr.w #4,d1 ; position the 3 flag bits (high bit zeroed)
or.b d1,d0 ; merge into QType high byte
move.b d0,QType(a0) ; save flags, mark the task initially inactive
moveq.l #noErr,d0 ; return success
rts ; all done
TITLE 'Time Manager - Multiply 32 by 32'
;_______________________________________________________________________
;
; Routine: MultAndMerge
; Inputs: D0 - 32 bit multiplier
; (return PC) - 32 bit multiplicand
; (return PC+4) - 32 bit merge mask
; Outputs: D0 - upper 32 bits of 64 bit product, merged with selected
; bits of lower 32 bits of 64 bit product as specified by
; merge mask.
; Destroys: A2, D1, D2, D3
; Calls: none
; Called by: PrimeTime, RmvTime
;
; Function: Performs a 32 by 32 bit multiply producing a 64 bit result.
; Same function as the 68020 MULU.L D0,D0:D1 instruction.
; The 64 bit product is then merged into a 32 bit result, by
; using a merge mask which has bits set corresponding to which
; bits in the low 32 bits of the product are to be merged into
; the corresponding bit positions of the high 32 bits of the
; product. If the bits specified in the merge mask an non-zero
; in the high 32 bits of the product, then a result of all ones
; will be returned to indicate overflow.
; This routine is used to perform fixed point multiplication,
; where the position of the implied binary point may vary.
;
; Note: D0 = A B, D1 := C D. Product is derived as follows.
; B*D
; + B*C
; + A*D
; + A*C
;
;_______________________________________________________________________
macro
mulud0d168000
; result in d0, d1
; trashes d2, d3
move.l d4,-(sp) ; preserve d4
move.l d1,d2 ; D2 := C D
move.l d1,d3 ; D3 := C D
mulu.w d0,d1 ; D1 := B*D
swap d1 ;
swap d3 ; D3 := D C
mulu.w d0,d3 ; D3 := B*C
swap d0 ; D0 := B A
ext.l d0 ; D0 := A (sign extended)
move.w d0,d4 ; D4 := A
beq.s @ShortMul ; if A is zero, skip next 2 mults
mulu.w d2,d4 ; D4 := A*D
swap d2 ; D2 := D C
mulu.w d2,d0 ; D0 := A*C
add.l d4,d3 ; D3 := A*D + B*C
clr.w d4 ;
addx.w d4,d4 ; D4 := carry from A*D + B*C
@ShortMul add.w d3,d1 ; add middle product to low product
swap d1 ; D1 := low 32 bits of product
move.w d4,d3 ; D3 := copy saved carry
swap d3 ; D3 := high 17 bits of A*D + B*C
addx.l d3,d0 ; D0 := high 32 bits of product
move.l (sp)+,d4 ; restore d4
endm
export MultAndMerge
MultAndMerge
movea.l (sp)+,a2 ; pop return address
move.l (a2)+,d1 ; get multiplicand
if forROM then
mulu.l d0,d0:d1 ; d0:d1 := d0*d1
else
tst.b CPUFlag ; are we on a machine with long multiply?
bz.s @noLongMultiply
mulu.l d0,d0:d1 ; d0:d1 := d0*d1
bra.s @didMultiply
@noLongMultiply
mulud0d168000 ; d0:d1 := d0*d1 (trash d2, d3)
@didMultiply
endif
move.l (a2)+,d2 ; get merge mask
beq.s @Done ; if zero, result in d0 is correct
and.l d2,d1 ; get the non-fraction bits from d1
add.l d0,d2 ; corresponding bits in d0 should be zero
subx.l d2,d2 ; d2 = -1 if d0 overflowed, else zero
or.l d2,d0 ; return d0 = -1 if overflow
or.l d1,d0 ; merge bits from d1 into d0
@Done jmp (a2) ; return to code after constant list
TITLE 'Time Manager - Prime Time Manager Task'
;_______________________________________________________________________
;
; Routine: PrimeTime
; Inputs: A0 - pointer to Time Manager Task to schedule
; D0 - [long] if >= 0, Delay Time in positive milliseconds
; if < 0, Delay Time in negated microseconds
; Outputs: D0 - error code (noErr)
; Destroys: none
; Calls: FreezeTime, ThawTime, MultAndMerge
; Called by: OsTrap dispatcher
;
; Function: Schedules a Time Manager Task to run after the specified
; Delay Time expires. The Delay Time may be specified in
; milliseconds, in which case, it must be a positive number,
; or it can be specified in microseconds, in which case, it
; must be negated first.
; Additionally, the TaskActiveBit of the QType field will
; be set to indicate that the timer task is currently active,
; and will be cleared when the specified time has expired.
;
; NOTE: The Time Manager does not support delay times as long as the
; maximum number of milliseconds that can be passed to this call.
; If delay time specified is too large, then the maximum delay
; time supported will be used instead.
;
;_______________________________________________________________________
export AfterFreezeTimeInPrimeTime
; a0-a2/d1-d2 saved by dispatcher
__PrimeTime move.l d3,-(sp) ; save d3 also
;_______________________________________________________________________
;
; start of code from Quicktime patch
; attempts to keep backlog from becoming very large
;
IF 0 THEN ; ex<3> <Sys7.1> Removed QuickTime patch
btst.b #ExtendedTmTaskBit, qType(a0)
beq.s @notExtended
lea 3+tmReserved(a0), a1
tst.l tmWakeUp(a0)
beq.s @startNew
tst.l d0
beq.s @checkCount
@startNew:
clr.b (a1)
bra.s @notExtended
@checkCount:
addq.b #1, (a1)
bpl.s @notExtended
bclr.b #ExtendedTmTaskBit, qType(a0)
@notExtended:
ENDIF ; ex<3> <Sys7.1> End of removed code
;
; end of code from Quicktime patch
;
;_______________________________________________________________________
tst.l d0 ; see if +msec or -µsec
bpl.s @msec ; µsec are negated, msec pos
@usec neg.l d0 ; get positive number of µsecs
convert UsToInternal,UsToIntFractBits ; convert µsec to internal
bra.s @ConvertDone ; join common code
@msec convert MsToInternal,MsToIntFractBits ; convert msec to internal
@ConvertDone
jsr FreezeTime ; setup to manipulate time queue
AfterFreezeTimeInPrimeTime
bset.b #TaskActiveBit,QType(a0); mark the task as active
bne.s @AlreadyActive ; if already on the queue don't touch it
btst.b #ExtendedTmTaskBit,QType(a0) ; check for extended tmTask
beq.s @AddToActive ; of standard tmTask, nothing special to do
move.l CurrentTime(a2),d2 ; get current time
move.l tmWakeUp(a0),d1 ; get wake time from last _PrimeTime
beq.s @SetNewWakeTime ; if not set, delay relative to CurrentTime
sub.l d2,d1 ; d1 := time since/till last wakeup
bpl.s @WakeInFuture ; if time till, just add to it
add.l d1,d0 ; subtract time since from desired delay
bcs.s @SetNewWakeTime ; if time still positive, use it
add.l d0,d2 ; new wakeup := old + delay
bne.s @WakeupInPast ; zero is special wakeup value, don't allow it
moveq.l #1,d2 ; use one instead of zero
@WakeupInPast
move.l d2,tmWakeUp(a0) ; update wakeup.
move.l d0,d1 ; remember negated delay
sub.l d0,BackLog(a2) ; remember how late we are
moveq.l #0,d0 ; for negative delay, use zero
lea ActivePtr-Qlink(a2),a1 ; A1 : previous := head
move.l QLink(a1),d2 ; D2 : next := previous.QLink
beq.s @Insert ; if empty, make it the head
exg.l a1,d2 ; A1 : previous := next (save old previous)
sub.l d1,tmCount(a1) ; add backlog of new task to old first task
exg.l a1,d2 ; restore prior previous and next ptrs
bra.s @Insert ; add it to the active list
@WakeInFuture
add.l d1,d0 ; add time till desired delay
@SetNewWakeTime
add.l d0,d2 ; new wakeup := old + delay
bne.s @StoreWakeup ; zero is special wakeup value, don't allow it
moveq.l #1,d2 ; use one instead of zero
@StoreWakeup
move.l d2,tmWakeUp(a0) ; update wakeup.
@AddToActive
add.l BackLog(a2),d0 ; run it after all pending tasks
lea ActivePtr-Qlink(a2),a1 ; A1 : previous := head
@SearchLoop move.l QLink(a1),d2 ; D2 : next := previous.QLink
beq.s @Insert ; if end, insert after previous
exg.l a1,d2 ; A1 : previous := next (save old previous)
move.l tmCount(a1),d1 ; get delay between previous and next
sub.l d1,d0 ; subtract from our delay time
bhs.s @SearchLoop ; loop until our delay between prev and next
add.l d1,d0 ; d0 := delay between previous and new
sub.l d0,d1 ; d1 := delay between new and next
move.l d1,tmCount(a1) ; adjust next task delay time
exg.l a1,d2 ; restore prior previous and next ptrs
@Insert move.l d2,QLink(a0) ; new task followed by next task
move.l d0,tmCount(a0) ; setup new task delay time
move.l a0,QLink(a1) ; previous task followed by new task
@AlreadyActive
bsr.s ThawTime ; done manipulating time queue
move.l (sp)+,d3 ; restore saved d3
moveq.l #noErr,d0 ; return success
rts ; all done
TITLE 'Time Manager - Timer 2 Interrupt Handler'
;_______________________________________________________________________
;
; Routine: Timer2Int
; Inputs: none
; Outputs: none
; Destroys: A0, A1, A2, A3, D0, D1, D2, D3
; Calls: FreezeTime, ThawTime, tmAddr service routine.
; Called by: VIA 1 system interrupt handler
;
; Function: Services the timer interrupt, and calls the service routine
; if task at the head of the list has expired, or continues
; it running if more time remaining. If nothing on timer
; list, just disables the timer.
;
; NOTE: The TaskActiveBit in the QType field will be cleared when the
; task timer expires so that applications can poll the timer for
; completion. If the tmAddr field is zero, the service routine
; will not be called. When the service routine is called, A0 points
; to the service routine itself, and A1 points to the expired
; Time Manager task.
;
;_______________________________________________________________________
export AfterFreezeTimeInTimer2Int
Timer2Int ; a0-a3/d0-d3 saved by IntHand
jsr FreezeTime ; stop the timer, adjust time remaining <4>
AfterFreezeTimeInTimer2Int
move.l ActivePtr(a2),d0 ; get pointer to first active timer task
beq.s ThawTime ; if nothing in queue, just exit
movea.l d0,a0 ; A0 := pointer to timer task
tst.l tmCount(a0) ; see if timer expired
bne.s ThawTime ; if not, let it continue running
move.l QLink(a0),ActivePtr(a2) ; remove it from the active list
bclr.b #TaskActiveBit,QType(a0); mark the task as completed
bsr.s ThawTime ; start next timer running
move.l tmAddr(a0),d0 ; get service routine address
beq.s @NoHandler ; if no service routine, just exit
movea.l a0,a1 ; A1 := pointer to queue element
movea.l d0,a0 ; A0 := address of service routine
jmp (a0) ; return through the service routine
@NoHandler rts ; all done
TITLE 'Time Manager - Thaw Time'
;_______________________________________________________________________
;
; Routine: ThawTime
; Inputs: A2 - ptr to TimeMgrPrivate
; D3.hi - saved SR (interrupt priority)
; D3.lo - value read from the low byte of the VIA timer masked
; to virtual ticks.
; Outputs: none
; Destroys: D1, D2, A1, A2
; Calls: none
; Called by: RmvTime, PrimeTime, Timer2Int
;
; Function: Starts timer, based upon head of timer list, adjusts
; time remaining for head of list. Restores interrupt
; priority level.
;
;_______________________________________________________________________
ThawTime move.l #$0000FFFF>>TickScale,d2; max range (internal form) of VIA timer
add.b TimerAdjust(a2),d3 ; add in the timer loading overhead
move.l ActivePtr(a2),d1 ; check pointer to first active timer task
beq.s @StartTimer ; if no tasks, just start timer with max
movea.l d1,a1 ; point to head of active list
move.l tmCount(a1),d1 ; get time remaining for head
sub.l BackLog(a2),d1 ; remove as much backlog as possible
bhs.s @NoBacklog ; if tmCount >= BackLog
neg.l d1 ; BackLog - tmCount
move.l d1,BackLog(a2) ; update backlog
moveq.l #0,d1 ; run immediatly
bra.s @FindMax ; update timer
@NoBackLog clr.l BackLog(a2) ; no backlog remaining
@FindMax cmp.l d2,d1 ; check remaining time against max
bhs.s @UseMax ; if remaining >= max, use the max instead
move.l d1,d2 ; otherwise, use time remaining
@UseMax sub.l d2,d1 ; remaining := remaining - timer value
move.l d1,tmCount(a1) ; update time remaining
@StartTimer movea.l VIA,a1 ; get base address of VIA1
lea vT2C(a1),a1 ; point to low byte of counter for speed
move.w d3,d1 ; save copy of adjusted original low byte
@Retry add.l d2,CurrentTime(a2) ; update current time
lsl.w #TickScale,d2 ; convert internal form to VIA form
lea vT2CH-vT2C(a1),a2 ; point to high byte for speed
; *** Begining of time critical section
eieioSTP
sub.b vT2C-vT2C(a1),d3 ; see how many ticks of overhead used
eieioSTP
sub.w d3,d2 ; subtract out overhead ticks
bls.s @Underflow ; if less than 1 tick, fix it up
; VIAs from Rockwell (which we have been shipping for several years) and possibly
; other vendors have a bug. If you load the counter high byte in the same clock
; as the old counter value is counting through zero, when the new counter value
; counts through zero the VIA will not generate an interrupt. To work around this
; "feature", we first load a dummy non-zero value into the high byte of the counter,
; and then load the value we really wanted. This should allow enough time to
; guarantee that it will not be counting through zero at the time we load the real
; counter value. This fixes the "AppleShare server hang problem".
eieioSTP
move.b d1,vT2CH-vT2CH(a2) ; *** ROCKWELL VIA FIX, DON'T REMOVE ***
eieioSTP
move.b d2,vT2C-vT2C(a1) ; setup timer low byte latch
eieioSTP
if use68020Opcodes then ; 68020 shifting is fast
lsr.w #8,d2 ; get high byte of time
eieioSTP
move.b d2,vT2CH-vT2CH(a2) ; load high byte of timer, start timer
eieioSTP
else ; 68000 shifting is slower than memory
move.w d2,-(sp) ; get high byte of time
eieioSTP
move.b (sp)+,vT2CH-vT2CH(a2) ; load high byte of timer, start timer
eieioSTP
endif
; *** End of time critical section
if forROM then
if hasPowerMgr then
movea.l PMgrBase,a2 ; PMgr gobals.
cmpi.b #1,PMgrRec.saveSpeedo(a2) ; see if we need to be idle
bne.s @RemainFast ; if not, remain running at fast speed.
tst.w Clock1M ; return processor to idle.
@RemainFast
endif
endif
swap d3 ; get saved sr from high word
move.w d3,sr ; restore interrupt priority level
rts ; all done
@Underflow add.w d2,d3 ; recompute original delay value
sub.b d3,d1 ; adjust initial timer low byte
neg.w d2 ; make excess time positive
movea.l TimeVars,a2 ; point to TimeMgrPrivate
add.w RetryAdjust(a2),d2 ; round up before conversion, add in some extra time
lsr.w #TickScale,d2 ; convert it to virtual ticks
add.l d2,BackLog(a2) ; remember how negative we are for next freeze
move.w d1,d3 ; restore initial timer low byte
bra.s @Retry ; now go reload the timer
endproc
TITLE 'Time Manager - Read 64 bit MicroSecond counter'
;_______________________________________________________________________ <4>
;
; Routine: MicroSeconds
; Inputs: none
; Outputs: A0/D0 - 64 bit counter (A0=High, D0=Low)
; Destroys: none
; Calls: none
; Called by: OsTrap dispatcher
;
; Function: Returns the value of the 64 bit microsecond counter, which
; is useful for timestamping.
;
;_______________________________________________________________________
__MicroSeconds: proc export ; a0-a2/d1-d2 saved by dispatcher
import FreezeTime
import ThawTime
with TimeMgrPrivate
move.l d3,-(sp)
jsr FreezeTime
move.b TimerLowSave(a2),d1 ; low byte of VIA timer
neg.b d1
ror.l #4,d1
move.w CurrentTime+2(a2),d1 ; get low word of current time
lea CurTimeThresh(a2),a1 ; point to CurTimeThresh
sub.w (a1),d1 ; CurrentTime := CurrentTime - CurTimeThresh
addi.w #ThreshInc,d1 ; compute additional time
rol.l #TickScale,d1 ; convert to un-scaled VIA time
mulu.w #InternalToUs>>16,d1 ; convert to microseconds
if 32-IntToUsFractBits-TickScale <> 1 then
lsl.l #32-IntToUsFractBits-TickScale,d1 ; align to form 16.16 fixed point result
else
add.l d1,d1 ; align to form 16.16 fixed point result
endif
add.w -(a1),d1 ; add in FractUSecs, set ccr.x to carry out
move.l -(a1),d0 ; LowUSecs
move.l -(a1),a0 ; HighUSecs
clr.w d1 ; clear out fraction bits
swap d1 ; get additional µsecs
addx.l d1,d0 ; add additional time to LowUSecs
subx.l d1,d1 ; -1 if ccr.x = 1, 0 if ccr.x = 0
sub.l d1,a0 ; propagate carry into HighUSecs
jsr ThawTime
move.l (sp)+,d3
rts
endproc
TITLE 'Time Manager - Freeze Time'
;_______________________________________________________________________
;
; Routine: FreezeTime
; Inputs: none
; Outputs: A2 - ptr to TimeMgrPrivate
; D3.hi - saved SR (interrupt priority)
; D3.lo - value read from the low byte of the VIA timer masked
; to virtual ticks.
; Destroys: D1, D2, A1
; Calls: none
; Called by: RmvTime, PrimeTime, Timer2Int
;
; Function: Saves current interrupt priority level, disables all interrupts.
; Reads the VIA timer 2, adjusts tmCount field of all active
; Time Manager Tasks to reflect actual time remaining.
;
;_______________________________________________________________________
FreezeTime proc export
with TimeMgrPrivate
move.w sr,d3 ; save interrupt priority level
swap d3 ; sr -> high word, zero -> low word
move.w #$0100-(1<<TickScale),d3; setup virtual tick mask
movea.l VIA,a1 ; get base address of VIA1
lea vT2CH(a1),a1 ; point to timer high byte for speed
movea.l TimeVars,a2 ; point to TimeMgrPrivate
ori.w #$0700,sr ; disable all interrupts
if forROM then
if hasPowerMgr then
eieioSTP
tst.w Clock16M ; force processor out of idle.
eieioSTP
endif
else
; NOP this out on machines without Power Mgr. chips
export PoundThreeNOPsHereIfNoPowerMgr
PoundThreeNOPsHereIfNoPowerMgr:
eieioSTP
tst.w Clock16M ; force processor out of idle.
eieioSTP
endif
; The VIA Timer is constantly decrementing, and after the high byte is read, but
; before the low byte is read, the low byte may decrement from 00 -> FF, which
; would mean that the high is off by one, which would be an error of 256 ticks.
; By reading the high byte twice, we can detect and correct this situation.
; We also correct for the case where the high byte counted from 00 -> FF, in which
; case the interrupt pending bit may have been incorrect at the time we read it.
eieioSTP
move.b vT2CH-vT2CH(a1),d2 ; get high byte of counter
eieioSTP
moveq.l #1<<T2IntBit,d1 ; setup mask to check int pending
eieioSTP
and.b vIFR-vT2CH(a1),d1 ; get interrupt pending bit
eieioSTP
neg.l d1 ; d1.hi := -1 if int pending, else 0
if use68020Opcodes then ; 68020 shifting is fast
move.b d2,d1 ; insert timer high byte
lsl.w #8,d1 ; position it in the right place
else ; 68000 shifting is slower than memory
move.b d2,-(sp) ; insert timer high byte
move.w (sp)+,d1 ; position it in the right place
endif
eieioSTP
move.b vT2C-vT2CH(a1),d1 ; insert timer low byte
eieioSTP
sub.b vT2CH-vT2CH(a1),d2 ; see if high byte changed
eieioSTP
beq.s @TimeOK ; if not, time is correct
subx.l d2,d2 ; d2 := -1 if counted through zero
or.l d2,d1 ; update sign bits
if use68020Opcodes then ; 68020 shifting is fast
eieioSTP
move.b vT2CH-vT2CH(a1),d1 ; re-read timer high byte
eieioSTP
lsl.w #8,d1 ; position it in the right place
else ; 68000 shifting is slower than memory
eieioSTP
move.b vT2CH-vT2CH(a1),-(sp) ; re-read timer high byte
eieioSTP
move.w (sp)+,d1 ; position it in the right place
endif
eieioSTP
move.b vT2C-vT2CH(a1),d1 ; insert timer low byte
eieioSTP
@TimeOK
eieioSTP
move.b d1,TimerLowSave(a2) ; save low byte of VIA timer <4>
moveq.l #(1<<TickScale)-1,d2 ; prepare to round to virtual ticks
add.l d2,d1 ; if virtual tick not complete, don't count it
and.b d1,d3 ; save VIA timer truncated to virtual ticks
asr.l #TickScale,d1 ; convert ticks to internal time form
sub.l d1,CurrentTime(a2) ; update current time
move.w CurrentTime+2(a2),d2 ; get low word of current time <4>
@chkThresh lea CurTimeThresh(a2),a1 ; point to CurTimeThresh <4>
cmp.w (a1),d2 ; see if next threshold has been reached <4>
bmi.s @threshOK ; if not reached yet, don't need to increment <4>
addi.w #ThreshInc,(a1) ; update the next threshold <4>
addi.l #USecsInc,-(a1) ; update microsecond counter (low word, and fract) <4>
bcc.s @chkThresh ; if no carry to prop, see if thresh adjusted <4>
addq.w #1,-(a1) ; propagate the carry <4>
bcc.s @chkThresh ; if no carry to prop, see if thresh adjusted <4>
addq.l #1,-(a1) ; propagate the carry <4>
bra.s @chkThresh ; see if threshold adjusted <4>
@threshOK ; <4>
move.l ActivePtr(a2),d2 ; get pointer to first active timer task
beq.s @UpdateBacklog ; if no active tasks, no backlog (d2=0)
movea.l d2,a1 ; setup pointer to task at head
moveq.l #0,d2 ; assume new backlog will be zero
sub.l BackLog(a2),d1 ; adjust the timer, account for backlog
bpl.s @Early ; extra time, no backlog of any kind
add.l tmCount(a1),d1 ; tmCount := tmCount - backlog
bcs.s @UpdateHead ; if no remaining backlog, use remaining count
sub.l d1,d2 ; setup remaining backlog
moveq.l #0,d1 ; no remaining time
@UpdateHead move.l d1,tmCount(a1) ; setup new time remaining
@UpdateBacklog
move.l d2,BackLog(a2) ; update backlog time, if any
rts ; all done
@Early add.l tmCount(a1),d1 ; add excess time to time remaining
bra.s @UpdateHead ; update the time remaining counter
endproc
TITLE 'Time Manager - Initialize Time Manager'
;_______________________________________________________________________
;
; Routine: InitTimeMgr
; Inputs: none
; Outputs: none
; Destroys: none
; Calls: none
; Called by: StartInit
;
; Function: Allocates and initializes the Time Manager's global data
; structures at system boot time. Sets up VIA 1 Timer2
; interrupt handler. Computes the timer adjustment value
; at runtime, since it is processor speed dependent.
;
;_______________________________________________________________________
InitTimeMgr proc export
import Timer2Int
import ThawTime
with TimeMgrPrivate
@SavedRegs reg a0-a4/d0-d5 ; registers to preserve
movem.l @SavedRegs,-(sp) ; save the registers
moveq.l #PrivateSize,d0 ; size to allocate
_NewPtr ,SYS,CLEAR ; allocate and clear the structure
move.l a0,TimeVars ; setup pointer to private storage
movea.l a0,a2 ; setup for ThawTime
if forROM then
move.w #(1<<(TickScale-1))\ ; round up before conversion
+(1<<TickScale),RetryAdjust(a2) ; add in some extra time
else
moveq #(1<<(TickScale-1))\ ; round up before conversion
+(2<<TickScale),d0 ; add in some extra time (value for 68000)
tst.b CPUFlag ; what processor do we have?
bz.s @gotRetryAdjust ; 68000, use value computed above
moveq #(1<<(TickScale-1))\ ; round up before conversion
+(1<<TickScale),d0 ; add in some extra time (value for 68020)
@gotRetryAdjust
move.w d0,RetryAdjust(a2) ; store the computed value
endif
lea Timer2Int,a1 ; get interrupt handler address
move.l a1,Lvl1DT+(T2IntBit*4) ; put into interrupt table
move.w sr,-(sp) ; save interrupt level
ori.w #$0700,sr ; disable interrupts
movea.l Via,a4 ; get VIA pointer
lea vT2C(a4),a1 ; point to low byte of timer 2 for speed
lea vT1C(a4),a3 ; point to low byte of timer 1 for speed
lea vACR(a4),a4 ; point to AUX control reg for speed
moveq.l #-$80+(1<<T2IntBit),d1 ; enable timer 2 interrupts
eieioSTP
move.b d1,vIER-vT2C(a1) ; initialize the interrupt enable bit
eieioSTP
moveq.l #~(1<<5),d5 ; mask to set timer 2 into timed interrupt mode
eieioSTP
and.b vACR-vACR(a4),d5 ; save old AUX control reg
eieioSTP
moveq.l #%00111111,d0 ; force timer 1 into one-shot mode
and.b d5,d0 ; clear the bits
eieioSTP
move.b d0,vACR-vACR(a4) ; setup temporary AUX control reg
eieioSTP
moveq.l #0,d3 ; setup timer low byte value
move.w sr,d3 ; get sr
swap d3 ; sr in high word
eieioSTP
move.b d1,vT1CH-vT1C(a3) ; load and start timer 1
eieioSTP
move.b d1,vT2CH-vT2C(a1) ; load and start timer 2
eieioSTP
move.b vT2C-vT2C(a1),d0 ; get timer 2 low byte
eieioSTP
sub.b vT1C-vT1C(a3),d0 ; get initial timer skew
eieioSTP
jsr ThawTime ; run the critical section, start timer
eieioSTP
move.b vT2C-vT2C(a1),d1 ; get timer 2 low byte
eieioSTP
sub.b vT1C-vT1C(a3),d1 ; get final timer skew
eieioSTP
sub.b d0,d1 ; don't count initial skew
subi.w #(($FFFF>>TickScale)<<TickScale),d1 ; subtract out loaded timer value
move.b d1,TimerAdjust(a0) ; setup the fudge factor
eieioSTP
move.b d5,vACR-vACR(a4) ; restore AUX control reg
eieioSTP
st vT2CH-vT2C(a1) ; load and start timer 2
eieioSTP
move.w (sp)+,sr ; restore interrupt level
movem.l (sp)+,@SavedRegs ; restore the registers
rts ; Time Manager is initialized
endproc
end
Reference in New Issue View Git Blame Copy Permalink