--- /dev/null
+#include "../kernel-68000.def"
+
+
+.globl platform_switchout,switchin,dofork,udata_shadow
+
+.mri 1
+
+; Switchout switches out the current process, finds another that is READY,
+; possibly the same process, and switches it in. When a process is
+; restarted after calling switchout, it thinks it has just returned
+; from switchout().
+platform_switchout:
+ or #$0700,sr
+ ; save machine state
+
+ clr.w -(sp) ; return code set here is ignored, but switchin can
+ ; return from either switchout OR dofork, so they must both write
+ ; U_DATA__U_SP with the following on the stack:
+ move.l usp,a0
+ movem.l a0/a2-a4/a6/d2-d7,-(sp)
+ move.l sp,U_DATA__U_SP(a5) ; this is where the SP is restored in switchin
+
+ ; find another process to run (may select this one again)
+ bsr getproc
+
+ move.l d0,-(sp)
+ bsr switchin
+
+ ; we should never get here
+ bra platform_monitor
+
+switchin:
+ or #$0700,sr
+ move.l 4(sp),a0 ; task to switch to
+ move.l P_TAB__P_UDATA_OFFSET(a0),a5
+ ; check u_data->u_ptab matches what we wanted
+ cmp.l U_DATA__U_PTAB(a5),a0
+ bne switchinfail
+
+ ; Switch the stacks back
+ move.l a5,udata_shadow ; For IRQs etc to recover A5 state
+ move.l U_DATA__U_SP(a5),a7
+
+ move.b #P_RUNNING,P_TAB__P_STATUS_OFFSET(a0)
+
+ ;
+ ; Get the user pages back. We can safely
+ ; do this above the parent kernel stack I think
+ ;
+ clr.l -(sp)
+ move.l a0,-(sp)
+ jsr pagemap_switch
+ addq #8,sp
+
+ ; runticks = 0
+ clr.w runticks
+
+ ; recover the task switch state
+ movem.l (sp)+,a0/a2-a4/a6/d2-d7
+ move.l a0,USP
+ ; and return code - FIXME: we have a different fork path so the d0
+ ; stacking can go
+ move.w (sp)+,d0
+
+ tst.b U_DATA__U_ININTERRUPT(a5)
+ bne keepoff ; in ISR, leave interrupts off
+ and #$F8FF,sr
+keepoff:
+ rts ; return with interrupts on
+
+switchinfail:
+ bsr outa0hex
+ lea badswitchmsg,a0
+ bsr outstring
+ ; something went wrong and we didn't switch in what we asked for
+ bra platform_monitor
+
+ ;
+ ; this gets exciting on the 68000 because our udata is not in a
+ ; fixed location except for swap only platforms. To deal with this
+ ; we return parent first and create a new return frame for the child
+ ;
+ ; Entry:
+ ; A5 = u_data pointer for parent
+ ; 4(sp) = child process table entry
+ ;
+ ; Exit:
+ ; We are running as the child, A5 = u_data pointer of child, on
+ ; child stack
+ ;
+dofork:
+ move.l 4(sp),a0 ; child p_tab
+ move.l a2,-(sp)
+
+ move.l P_TAB__P_UDATA_OFFSET(a0),a1 ; child udata
+
+ ; Copy the udata
+ ; FIXME: we don't need to copy the stack too!
+
+ move.l a5,a2
+ move.w #255,d0
+loop:
+ move.l (a2)+,(a1)+
+ dbra d0,loop
+
+
+ ;
+ ; Save the child PID for later and the udata offset
+ ;
+ move.w P_TAB__P_PID_OFFSET(a0),-(sp)
+ move.l P_TAB__P_UDATA_OFFSET(a0),-(sp)
+ ;
+ ; Configure the child udata now we copied it
+ ; BUG: child udata is NULL ????
+
+ move.l P_TAB__P_UDATA_OFFSET(a0),-(sp)
+ move.l a0,-(sp)
+ jsr makeproc
+ addq #8,sp
+ ;
+ ; The memory map is clone by ptab_alloc (we might want to
+ ; adjust that bit)
+ ;
+ ;tst.l d0
+ ;bne forked_up
+
+ move.l (sp)+,a2 ; Get the udata pointer back
+ ;
+ ; Now build a custom return frame for the child
+ ;
+ lea.l 1024(a2),a1 ; End of stack
+ ;
+ ; Copy over the parent top of stack return info
+ ;
+ ; FIXME: This assumes 68000 trap format. For the 68010
+ ; there will be 4 words not 3
+ ;
+ move.l 1020(a5),-(a1) ; Copy the PC
+ move.w 1018(a5),-(a1) ; Copy the status word
+ move.l 1014(a5),-(a1) ; Copy the A5 save of the parent
+ ; needed for PIC processes
+ ;
+ ; Stack a return address
+ ;
+ move.l #forkreturn,-(a1)
+ ;
+ ; USP has to be in a0
+ ;
+ move.l usp,a0
+ ;
+ ; And a frame as if we did a switchout
+ ;
+ move.w #0,-(a1)
+ movem.l a0/a2-a4/a6/d2-d7,-(a1)
+ move.l a1,U_DATA__U_SP(a2) ; Set the stack pointer
+
+ ; And carry on as the parent
+ move.w (sp)+,d0 ; child pid
+ move.l (sp)+,a2
+ clr.w runticks
+ rts
+forked_up:
+ moveq #-1,d0 ; parent, failed
+ rts
+;
+; This code gets called when we resume the child
+;
+forkreturn:
+ ; Wipe any stray kernel data
+ moveq #0,d1
+ move.l d1,a0
+ move.l d1,a1
+ move.l d1,a2
+ move.l d1,a3
+ move.l d1,a4
+ move.l d1,a6
+ move.l d1,d2
+ move.l d1,d3
+ move.l d1,d4
+ move.l d1,d5
+ move.l d1,d6
+ move.l d1,d7
+ ; recover A5 to match the parent
+ move.l (sp)+,a5
+ ; and RTE to the same address (which is fine as the user memory
+ ; has already been juggled if needed).
+ rte
+
+badswitchmsg: ascii "_switchin: FAIL"
+ byte 13,10,0
+.even
$(DOBJS): %.o: ../dev/%.c
$(CROSS_CC) $(CROSS_CCOPTS) -c $<
+tricks.S: ../lib/68000flat.S
+
clean:
rm -f *.o fuzix.elf loader.elf loader.map loader.bin core *~
#include "../kernel-68000.def"
-
-.globl platform_switchout,switchin,dofork,udata_shadow
-
-.mri 1
-
-; Switchout switches out the current process, finds another that is READY,
-; possibly the same process, and switches it in. When a process is
-; restarted after calling switchout, it thinks it has just returned
-; from switchout().
-platform_switchout:
- or #$0700,sr
- ; save machine state
-
- clr.w -(sp) ; return code set here is ignored, but switchin can
- ; return from either switchout OR dofork, so they must both write
- ; U_DATA__U_SP with the following on the stack:
- move.l usp,a0
- movem.l a0/a2-a4/a6/d2-d7,-(sp)
- move.l sp,U_DATA__U_SP(a5) ; this is where the SP is restored in switchin
-
- ; find another process to run (may select this one again)
- bsr getproc
-
- move.l d0,-(sp)
- bsr switchin
-
- ; we should never get here
- bra platform_monitor
-
-switchin:
- or #$0700,sr
- move.l 4(sp),a0 ; task to switch to
- move.l P_TAB__P_UDATA_OFFSET(a0),a5
- ; check u_data->u_ptab matches what we wanted
- cmp.l U_DATA__U_PTAB(a5),a0
- bne switchinfail
-
- ; Switch the stacks back
- move.l a5,udata_shadow ; For IRQs etc to recover A5 state
- move.l U_DATA__U_SP(a5),a7
-
- move.b #P_RUNNING,P_TAB__P_STATUS_OFFSET(a0)
-
- ;
- ; Get the user pages back. We can safely
- ; do this above the parent kernel stack I think
- ;
- clr.l -(sp)
- move.l a0,-(sp)
- jsr pagemap_switch
- addq #8,sp
-
- ; runticks = 0
- clr.w runticks
-
- ; recover the task switch state
- movem.l (sp)+,a0/a2-a4/a6/d2-d7
- move.l a0,USP
- ; and return code - FIXME: we have a different fork path so the d0
- ; stacking can go
- move.w (sp)+,d0
-
- tst.b U_DATA__U_ININTERRUPT(a5)
- bne keepoff ; in ISR, leave interrupts off
- and #$F8FF,sr
-keepoff:
- rts ; return with interrupts on
-
-switchinfail:
- bsr outa0hex
- lea badswitchmsg,a0
- bsr outstring
- ; something went wrong and we didn't switch in what we asked for
- bra platform_monitor
-
- ;
- ; this gets exciting on the 68000 because our udata is not in a
- ; fixed location except for swap only platforms. To deal with this
- ; we return parent first and create a new return frame for the child
- ;
- ; Entry:
- ; A5 = u_data pointer for parent
- ; 4(sp) = child process table entry
- ;
- ; Exit:
- ; We are running as the child, A5 = u_data pointer of child, on
- ; child stack
- ;
-dofork:
- move.l 4(sp),a0 ; child p_tab
- move.l a2,-(sp)
-
- move.l P_TAB__P_UDATA_OFFSET(a0),a1 ; child udata
-
- ; Copy the udata
- ; FIXME: we don't need to copy the stack too!
-
- move.l a5,a2
- move.w #255,d0
-loop:
- move.l (a2)+,(a1)+
- dbra d0,loop
-
-
- ;
- ; Save the child PID for later and the udata offset
- ;
- move.w P_TAB__P_PID_OFFSET(a0),-(sp)
- move.l P_TAB__P_UDATA_OFFSET(a0),-(sp)
- ;
- ; Configure the child udata now we copied it
- ; BUG: child udata is NULL ????
-
- move.l P_TAB__P_UDATA_OFFSET(a0),-(sp)
- move.l a0,-(sp)
- jsr makeproc
- addq #8,sp
- ;
- ; The memory map is clone by ptab_alloc (we might want to
- ; adjust that bit)
- ;
- ;tst.l d0
- ;bne forked_up
-
- move.l (sp)+,a2 ; Get the udata pointer back
- ;
- ; Now build a custom return frame for the child
- ;
- lea.l 1024(a2),a1 ; End of stack
- ;
- ; Copy over the parent top of stack return info
- ;
- ; FIXME: This assumes 68000 trap format. For the 68010
- ; there will be 4 words not 3
- ;
- move.l 1020(a5),-(a1) ; Copy the PC
- move.w 1018(a5),-(a1) ; Copy the status word
- move.l 1014(a5),-(a1) ; Copy the A5 save of the parent
- ; needed for PIC processes
- ;
- ; Stack a return address
- ;
- move.l #forkreturn,-(a1)
- ;
- ; USP has to be in a0
- ;
- move.l usp,a0
- ;
- ; And a frame as if we did a switchout
- ;
- move.w #0,-(a1)
- movem.l a0/a2-a4/a6/d2-d7,-(a1)
- move.l a1,U_DATA__U_SP(a2) ; Set the stack pointer
-
- ; And carry on as the parent
- move.w (sp)+,d0 ; child pid
- move.l (sp)+,a2
- clr.w runticks
- rts
-forked_up:
- moveq #-1,d0 ; parent, failed
- rts
-;
-; This code gets called when we resume the child
-;
-forkreturn:
- ; Wipe any stray kernel data
- moveq #0,d1
- move.l d1,a0
- move.l d1,a1
- move.l d1,a2
- move.l d1,a3
- move.l d1,a4
- move.l d1,a6
- move.l d1,d2
- move.l d1,d3
- move.l d1,d4
- move.l d1,d5
- move.l d1,d6
- move.l d1,d7
- ; recover A5 to match the parent
- move.l (sp)+,a5
- ; and RTE to the same address (which is fine as the user memory
- ; has already been juggled if needed).
- rte
-
-badswitchmsg: ascii "_switchin: FAIL"
- byte 13,10,0
-.even
+#include "../lib/68000flat.S"
public / FUZIX.git / commitdiff