|	.file "swap.s.68k"|	ident	"@(#)cls4:lib/task/task/swap.s.68k	1.1"|##############################################################################|  | C++ source for the C++ Language System, Release 3.0.  This product| is a new release of the original cfront developed in the computer| science research center of AT&T Bell Laboratories.| | Copyright (c) 1991 AT&T and UNIX System Laboratories, Inc.| Copyright (c) 1984, 1989, 1990 AT&T.  All Rights Reserved.| || THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE of AT&T and UNIX System|	| Laboratories, Inc.  The copyright notice above does not evidence| any actual or intended publication of such source code.| ||##############################################################################| |	swap of DEDICATED| call swap(*running_task, *to_run_task, is_new_child, running_is_terminated)| This routine saves the fp in running's t_framep.| If running is a SHARED task, we must save its stack size as well,| although the stack does not need to be copied out here.| It then restores to_run's t_framep to be the current fp.| If to_run is a new child, it explicitly restores the registers from| New_task_regs, and returns without movem to restore the regs saved in| the stack.| If to_run is not a new child, it restores all the registers saved in| the frame on returning.| If running_task is TERMINATED, then we don't need to do a save.| NOTE:  assumes all functions return values in d0.| The following constants are displacements of elements in class task:| t_framep, th, t_basep, t_size, t_savearea, and t_mode.TFRAME = 20TH = 24TBASEP = 32TSIZE = 36TSAVE = 40TMODE = 52| The following constants are displacements from the fp to function args.ARG1 = 8ARG2 = 12ARG3 = 16ARG4 = 20ARG5 = 24	.text	.globl	_swap_swap:	link	a6,#-40	moveml	#0x3cfc,sp@		| save all user regs (d2-d7, a2-a5)	movl	a6@(ARG2),a1		| a1 = to_run	movl	a6@(ARG4),d0		| d0 = running_is_terminated	bnes	L_RESTORE		| if running is TERMINATED					|	skip the save	movl	a6@(ARG1),a0		| a0 = running	| save state of running task	movl	a6,a0@(TFRAME)		| running->t_framep = fp (a6)	movl	a0@(TMODE),d0		| d0 = running->t_mode	cmpl	#2,d0			| if running->t_mode == SHARED	bnes	L_RESTORE	| the code here to save the t_size is the same as for sswap	movl	a0@(TBASEP),d0		| d0 = running->t_basep	subl	sp,d0			| d0 = running->t_basep - sp	addql	#4,d0			| (size in bytes)	asrl	#2,d0			| d0 /= 4 (size in ints)	movl	d0,a0@(TSIZE)		| running->t_size = d0L_RESTORE:	movl	a6@(ARG3),d1		| d1 = is_new_child	| restore state of to_run task	movl	a1@(TFRAME),a6		| a6 (fp) = to_run->t_framep	| if is_new_child, restore registers	tstl	d1	beqs	L_RET	| new child task effectively returns from task::task, so we need	| to set the return value to "this"	movl	a1@(TH),d0		| d0 = to_run->th	lea	_New_task_regs,a1	| a1 = address of New_task_regs	movl	a1@,d2	movl	a1@(4),d3	movl	a1@(8),d4	movl	a1@(12),d5	movl	a1@(16),d6	movl	a1@(20),d7	movl	a1@(32),a2	movl	a1@(36),a3	movl	a1@(40),a4	movl	a1@(44),a5	unlk	a6			| NOTE:  movem not needed here.	rtsL_RET:	moveml	a6@(-40),#0x3cfc	| restore all user regs (d2-d7, a2-a5)	unlk	a6	rts|	swap of SHARED| sswap(*running, *prevOnStack, *to_run, is_new_child, running_is_terminated)| This routine saves the fp in running's t_framep and the stack size in t_size.| Then it copies out the target stack to prevOnStack's t_savearea.| If to_run is not a new child, it then copies the saved stack of to_run | (from t_savearea) to the target stack, and then restores to_run's t_framep | to be the current fp.  We don't need to restore state of a child | to_run object, because it's already in place.| If running_task is TERMINATED, then we don't need to do a save,| and if running_task is TERMINATED and equals prevOnStack, then we don't| have to do the stack copy.| NOTE:  assumes all functions return values in d0.	.text	.globl	_sswap_sswap:	link	a6,#-40	moveml	#0x3cfc,sp@		| save all user regs (d2-d7, a2-a5)	movl	a6@(ARG1),a1		| a1 = running	movl	a6@(ARG2),a2		| a2 = prevOnStack	movl	a6@(ARG5),d0		| d0 = running_is_terminated	bnes	L_SKIP			| if running is TERMINATED					|	skip the save	|save hw state of running	movl	a6,a1@(TFRAME)		| running->t_framep = fp (a6)	movl	a1@(TBASEP),d0		| d0 = running->t_basep	subl	sp,d0			| d0 = running->t_basep - sp	addql	#4,d0			| (size in bytes)	asrl	#2,d0			| d0 /= 4 (size in ints)	movl	d0,a1@(TSIZE)		| running->t_size = d0	bra	L_SAVEL_SKIP:	cmpl	a1,a2			| if running == prevOnStack	beq	L_REST			|	skip prevOnStack saveL_SAVE:	|copy out target stack to prevOnStack->t_savearea	movl	a2@(TSIZE),d2		| d2 = prevOnStack->t_size (count)	movl	d2,sp@-			| push count arg on stack	jsr	_swap_call_new		| get count bytes of storage	addql	#4,sp			| pop arg off stack	asll	#2,d2			| scale d2 to bytes	addl	d2,d0			| d0 = base of new stack, plus 1 long	subql	#4,d0			| d0 = base of new stack	movl	d0,a0			| a0 = base of new stack (to)	movl	a0,a2@(TSAVE)		| prevOnStack->t_savearea = a0 (to)	movl	a2@(TBASEP),a1		| a1 = prevOnStack->t_basep (from)	addql	#4,a0			| prepare for predecrement	addql	#4,a1			| ditto	movl	a2@(TSIZE),d0		| d0 = prevOnStack->t_size (count)	tstl	d0	beqs	L2			| if size == 0, goto L2	subql	#1,d0			| for dbraL1:	| copy out loop	movl	a1@-,a0@-		| *--to = *--from	dbra	d0,L1			| if --d0 != 0, goto L1L2:L_REST:	movl	a6@(ARG4),d0		| d0 = is_new_child	bnes	L6			| if is_new_child != 0					|	skip the copy-in loop	|copy into target stack from to_run->t_savearea	movl	a6@(ARG3),a2		| a2 = to_run	movl	a2@(TBASEP),a0		| a0 = to_run->t_basep (to)	movl	a2@(TSIZE),d0		| d0 = to_run->t_size (count)	| Kick up the sp if new stack will be taller than current.	asll	#2,d0			| d0 = new stack height in bytes	subl	d0,a0			| a0 = target sp	subl	sp,a0			| a0 = a0 - sp	tstl	a0	bges	L3			| if a0 < 0	addl	a0,sp			|	kick up spL3:	movl	a2@(TBASEP),a0		| a0 = to_run->t_basep (to)	movl	a2@(TSAVE),a1		| a1 = to_run->t_savearea (from)	addql	#4,a1			| prepare for predecrement	addql	#4,a0			| ditto	movl	a2@(TSIZE),d0		| d0 = to_run->t_size (count)	tstl	d0	beqs	L5			| if size == 0, goto L5	subql	#1,d0			| for dbraL4:	| copy in loop	movl	a1@-,a0@-		| *--to = *--from	dbra	d0,L4			| if --d0 != 0, goto L4L5:	| restore state of to_run	movl	a2@(TFRAME),a6		| fp (a6) = to_run->t_framep	| finally, delete to_run's t_savearea	movl	a2@(TSIZE),d1		| d1 = to_run->t_size	asll	#2,d1			| scale size to bytes	movl	a2@(TSAVE),a0		| a0 = to_run->t_savearea	subl	d1,a0			| get low address of savearea	addql	#4,a0	movl	a0,sp@-			| push pointer to savearea on stack	jsr	_swap_call_delete	| delete to_run->t_savearea	addql	#4,sp			| pop arg off stack	movl	#0,a2@(TSAVE)		| to_run->t_savearea = 0L6:	moveml	a6@(-40),#0x3cfc	| restore all user regs (d2-d7, a2-a5)	unlk	a6	rts