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view level2/modules/kernel/falltsk.asm @ 3170:18306d646f71
mc09: First release of working L2 port to MC09 platform
Kernel has conditional code so should build for all targets, but it's
been split out into a separate file to avoid polluting the main code.
The included system call source code only has minor conditional
additions so it is shared.
| author | Neal Crook <foofoobedoo@gmail.com> |
|---|---|
| date | Thu, 20 Apr 2017 20:15:19 +0100 |
| parents | 2d22d31bc74b |
| children |
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************************************************** * System Call: F$AllTsk * * Function: Allocate process task number * * Input: X = Process descriptor pointer * * Output: None * * Error: CC = C bit set; B = error code * FAllTsk ldx R$X,u get pointer to process descriptor L0C58 ldb P$Task,x already have a task #? bne L0C64 yes, return bsr L0CA6 find a free task bcs L0C65 error, couldn't get one, return stb P$Task,x save task # bsr L0C79 load MMU with task L0C64 clrb clear errors L0C65 rts return ************************************************** * System Call: F$DelTsk * * Function: Deallocate process task number * * Input: X = Process descriptor pointer * * Output: None * * Error: CC = C bit set; B = error code * FDelTsk ldx R$X,u L0C68 ldb P$Task,x grab the current task number beq L0C64 if system (or released), exit clr P$Task,x force the task number to be zero bra L0CC3 do a F$RelTsk TstImg equ * IFNE H6309 tim #ImgChg,P$State,x ELSE * pshs b ldb P$State,x bitb #ImgChg * puls b ENDC beq L0C65 if not, exit now: don't clear carry, it's not needed fcb $8C skip LDX, below ************************************************** * System Call: F$SetTsk * * Function: Set process task DAT registers * * Input: X = Process descriptor pointer * * Output: None * * Error: CC = C bit set; B = error code * FSetTsk ldx R$X,u get process descriptor pointer L0C79 equ * IFNE H6309 aim #^ImgChg,P$State,x flag DAT image change in process descriptor ELSE * pshs b ldb P$State,x andb #^ImgChg stb P$State,x * puls b ENDC clr <D.Task1N task 1 DAT image has changed andcc #^Carry clear carry pshs cc,d,x,u preserve everything ldb P$Task,x get task # leau <P$DATImg,x point to DAT image ldx <D.TskIPt get task image table pointer lslb account for 2 bytes/entry stu b,x save DAT image pointer in task table cmpb #2 is it either system or GrfDrv? bhi L0C9F no, return IFNE mc09 lda <D.TINIT ELSE ldx #DAT.Regs update system DAT image ENDC lbsr L0E93 go bash the hardware L0C9F puls cc,d,x,u,pc ************************************************** * System Call: F$ResTsk * * Function: Reserve task number * * Input: None * * Output: B = Task number * * Error: CC = C bit set; B = error code * FResTsk bsr L0CA6 stb R$B,u L0CA5 rts * Find a free task in task map * Entry: None * Exit : B=Task # L0CA6 pshs x preserve X ldb #$02 get starting task # (skip System/Grfdrv) ldx <D.Tasks get task table pointer L0CAC lda b,x task allocated? beq L0CBA no, allocate it & return incb move to next task cmpb #$20 end of task list? bne L0CAC no, keep looking comb set carry for error ldb #E$NoTask get error code puls x,pc L0CBA stb b,x flag task used (1 cycle faster than inc) * orb <D.SysTsk merge in system task # ??? always 0 clra clear carry L0CBF puls x,pc restore & return ************************************************** * System Call: F$RelTsk * * Function: Release task number * * Input: B = Task number * * Output: None * * Error: CC = C bit set; B = error code * FRelTsk ldb R$B,u Get task # to release L0CC3 pshs b,x Preserve it & X * ??? No idea why this stuff is done. D.SysTsk is ALWAYS 0. * Even GrfDrv never changes it. * ldb <D.SysTsk Get system task # * comb Invert it * andb ,s Mask with requested task tstb check out B beq L0CD0 If system task, don't bother deleting the task ldx <D.Tasks Get task table ptr clr b,x Clear out the task L0CD0 puls b,x,pc Restore regs & return * Sleeping process update (Gets executed from clock) * Could move this code into Clock, but what about the call to F$AProc (L0D11)? * It probably will be OK... but have to check. * Possible, move ALL software-clock code into OS9p2, and therefore * have it auto-initialize? All hardware clocks would then be called * just once a minute. L0CD2 ldx <D.SProcQ Get sleeping process Queue ptr beq L0CFD None (no one sleeping), so exit IFNE H6309 tim #TimSleep,P$State,x Is it a timed sleep? ELSE ldb P$State,x bitb #TimSleep ENDC beq L0CFD No, exit: waiting for signal/interrupt ldu P$SP,x Yes, get his stack pointer ldd R$X,u Get his sleep tick count IFNE H6309 decd decrement sleep count ELSE subd #$0001 ENDC std R$X,u Save it back bne L0CFD Still more ticks to go, so exit * Process needs to wake up, update queue pointers L0CE7 ldu P$Queue,x Get next process in Queue bsr L0D11 activate it leax ,u point to new process beq L0CFB don't exist, go on IFNE H6309 tim #TimSleep,P$State,x is it in a timed sleep? ELSE ldb P$State,x bitb #TimSleep ENDC beq L0CFB no, go update process table ldu P$SP,x get it's stack pointer ldd R$X,u any sleep time left? beq L0CE7 no, go activate next process in queue L0CFB stx <D.SProcQ Store new sleeping process pointer L0CFD dec <D.Slice Any time remaining on process? bne L0D0D Yes, exit inc <D.Slice reset slice count ldx <D.Proc Get current process pointer beq L0D0D none, return IFNE H6309 oim #TimOut,P$State,x put him in a timeout state ELSE ldb P$State,x orb #TimOut stb P$State,x ENDC L0D0D clrb rts