; better.
;
interrupt_handler:
- ; Do not use the stack before the switch...
-
- ; FIXME: add profil support here (need to keep profil ptrs
- ; unbanked if so ?)
-
- lda #1
- sta U_DATA__U_ININTERRUPT
-
- ; switch stacks
- sts istack_switched_sp
- lds #istack_top-2
- ; FIXME: check store/dec order might not need to be -2 here!!!!
-
- jsr map_save
-
- lda 0 ; save address 0 contents for checking
-
- ; preserves registers
- jsr map_kernel
- ;
- ; kernel_flag is in the kernel map so we need to map early, we
- ; need to map anyway for trap_signal
- ;
- ldb U_DATA__U_INSYS ; In a system call ?
- bne in_kernel
-
- ; we're not in kernel mode, check for signals and fault
- cmpa #0x7E ; JMP at 0
- beq nofault
- jsr map_process_always ; map the process
- lda #0x7E ; put it back
- sta 0 ; write
- jsr map_kernel ; restore the map
- ldx #11 ; SIGSEGV
- jsr trap_signal ; signal the user with a fault
+ ; Do not use the stack before the switch...
+ ; FIXME: add profil support here (need to keep profil ptrs
+ ; unbanked if so ?)
+
+ lda #1
+ sta U_DATA__U_ININTERRUPT
+
+ ; switch stacks
+ sts istack_switched_sp
+ lds #istack_top-2
+ ; FIXME: check store/dec order might not need to be -2 here!!!!
+
+ jsr map_save
+
+ lda 0 ; save address 0 contents for checking
+
+ ; preserves registers
+ jsr map_kernel
+ ;
+ ; kernel_flag is in the kernel map so we need to map early, we
+ ; need to map anyway for trap_signal
+ ;
+ ldb U_DATA__U_INSYS ; In a system call ?
+ bne in_kernel
+
+ ; we're not in kernel mode, check for signals and fault
+ cmpa #0x7E ; JMP at 0
+ beq nofault
+ jsr map_process_always ; map the process
+ lda #0x7E ; put it back
+ sta 0 ; write
+ jsr map_kernel ; restore the map
+ ldx #11 ; SIGSEGV
+ jsr trap_signal ; signal the user with a fault
nofault:
in_kernel:
- ; set inint to true
- lda #1
- sta _inint
-
- ;
- ; If the kernel decides to task switch it will set
- ; _need_resched, and will only do so if the caller was in
- ; user space so has a free kernel stack
-
- jsr _platform_interrupt
-
- clr _inint
- ldx istack_switched_sp ; stack back
- clr U_DATA__U_ININTERRUPT
- lda U_DATA__U_INSYS
- bne interrupt_return_x
- lda _need_resched
- beq no_switch
-
- clr _need_resched
- stx U_DATA__U_SYSCALL_SP ; save again somewhere safe for
+ ; set inint to true
+ lda #1
+ sta _inint
+
+ ;
+ ; If the kernel decides to task switch it will set
+ ; _need_resched, and will only do so if the caller was in
+ ; user space so has a free kernel stack
+
+ jsr _platform_interrupt
+
+ clr _inint
+ ldx istack_switched_sp ; stack back
+ clr U_DATA__U_ININTERRUPT
+ lda U_DATA__U_INSYS
+ bne interrupt_return_x
+ lda _need_resched
+ beq no_switch
+
+ clr _need_resched
+ stx U_DATA__U_SYSCALL_SP ; save again somewhere safe for
; preemption
- ; Pre emption occurs on the task stack. Conceptually its a
- ; not quite a syscall
- lds #kstack_top
- jsr _chksigs ; check signal state
- ;
- ldx U_DATA__U_PTAB
- ; Move to ready state
- lda #P_READY
- sta P_TAB__P_STATUS_OFFSET,x
- ; Sleep on the kernel stack, IRQs will get re-enabled if need
- ; be
- jsr _platform_switchout
- ;
- ; We will resume here after the pre-emption. Get back onto
- ; the user stack and map ourself in
- jsr map_process_always
- lds U_DATA__U_SYSCALL_SP
- bra intdone
+ ; Pre emption occurs on the task stack. Conceptually its a
+ ; not quite a syscall
+ lds #kstack_top
+ jsr _chksigs ; check signal state
+ ;
+ ldx U_DATA__U_PTAB
+ ; Move to ready state
+ lda #P_READY
+ sta P_TAB__P_STATUS_OFFSET,x
+ ; Sleep on the kernel stack, IRQs will get re-enabled if need
+ ; be
+ jsr _platform_switchout
+ ;
+ ; We will resume here after the pre-emption. Get back onto
+ ; the user stack and map ourself in
+ jsr map_process_always
+ lds U_DATA__U_SYSCALL_SP
+ bra intdone
; Not task switching - the easy and usual path
no_switch:
- ; On a return from an interrupt restore the old mapping as it
- ; will vary during kernel activity and we need to put it put
- ; it back as it was before the interrupt
- ; pre-emption is handled differently...
- jsr map_restore
- lds istack_switched_sp
+ ; On a return from an interrupt restore the old mapping as it
+ ; will vary during kernel activity and we need to put it put
+ ; it back as it was before the interrupt
+ ; pre-emption is handled differently...
+ jsr map_restore
+ lds istack_switched_sp
intdone:
- ; we're not in kernel mode, check for signals
- ; runs off the user stack
- pshs y
- jsr dispatch_process_signal
- puls y
+ ; we're not in kernel mode, check for signals
+ ; runs off the user stack
+ pshs y
+ jsr dispatch_process_signal
+ puls y
interrupt_return:
- rti
+ rti
interrupt_return_x:
- tfr x,s
- jsr map_restore
- bra interrupt_return
+ tfr x,s
+ jsr map_restore
+ bra interrupt_return
; Enter with X being the signal to send ourself
trap_signal:
- pshs x
- ldx U_DATA__U_PTAB ; ssig(pid, X)
- jsr _ssig
- puls x,pc
+ pshs x
+ ldx U_DATA__U_PTAB ; ssig(pid, X)
+ jsr _ssig
+ puls x,pc
; Called from process context (hopefully)
null_handler:
- ; kernel jump to NULL is bad
- lda U_DATA__U_INSYS
- beq trap_illegal
- ; user is merely not good
- ; check order of push arguments !!
- ldx #7
- ldy U_DATA__U_PTAB
- ldd #10 ; signal (getpid(), SIGBUS)
- pshs d,y
- swi
- puls d,y
- ldd #0
- tfr d,x
- pshs d,x
- swi ; exit
-
-
+ ; kernel jump to NULL is bad
+ lda U_DATA__U_INSYS
+ beq trap_illegal
+ ; user is merely not good
+ ; check order of push arguments !!
+ ldx #7
+ ldy U_DATA__U_PTAB
+ ldd #10 ; signal (getpid(), SIGBUS)
+ pshs d,y
+ swi
+ puls d,y
+ ldd #0
+ tfr d,x
+ pshs d,x
+ swi ; exit
illegalmsg: .ascii "[trap_illegal]"
- .db 13,10,0
+ .db 13,10,0
trap_illegal:
- ldx #illegalmsg
- jsr outstring
- jsr _platform_monitor
+ ldx #illegalmsg
+ jsr outstring
+ jsr _platform_monitor
-dpsmsg: .ascii "[dispsig]"
- .db 13,10,0
+dpsmsg: .ascii "[dispsig]"
+ .db 13,10,0
-nmimsg: .ascii "[NMI]"
- .db 13,10,0
+nmimsg: .ascii "[NMI]"
+ .db 13,10,0
nmi_handler:
lds #istack_top-2 ; We aren't coming back so this is ok
public / FUZIX.git / commitdiff