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/*===========================================================================

//

//      vec_ivsr.S

//

//      SPARClite vectors: interrupt vector service routine

//

//===========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

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//####ECOSGPLCOPYRIGHTEND####

//===========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    hmt

// Contributors: hmt

// Date:         1999-02-20

// Purpose:      SPARClite vector code

// Description:  see vectors.S; this is the default vector service routine

//               for interrupts.

//

//####DESCRIPTIONEND####

//

//=========================================================================*/

!----------------------------------------------------------------------------

//      .file   "vec_ivsr.S"

!----------------------------------------------------------------------------

#include 

#include 

#ifdef CYGPKG_KERNEL

# include 

#else

# undef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

# undef CYGFUN_HAL_COMMON_KERNEL_SUPPORT

#endif

!------------------------------------------------------------------------

#include 

#define DELAYS_AFTER_WRPSR_SAME_WINDOW

#define DELAYS_AFTER_WRWIM

! Macro to mark the stack as we descend, for debugging, because it is likely

! that actually running the ISR won~t touch the stack, but the memory needs

! to be there.  Normally blank.

//#define       MARKSTACKUSED st %sp, [ %sp ]

#define MARKSTACKUSED

!------------------------------------------------------------------------

        .text

!---------------------------------------------------------------------------

! default interrupt VSR, which calls the appropriate ISR after scheduler

! lock and interrupt masking, then interrupt_end().  interrupt_end() must be

! called with interrupts enabled, on the original thread stack (no separate

! interrupt stack) or with interrupts masked, on the original stack (when

! separate interrupt stack is supported).

        .global hal_default_interrupt_vsr

hal_default_interrupt_vsr:

        ! here,locals have been set up as follows:

        ! %l0 = psr (with this CWP/window-level in it)

        ! %l1 = pc

        ! %l2 = npc

        ! %l3 = vector number (1-15 for interrupts)

        ! and we are in our own register window, though it is likely that

        ! the next one will need to be saved before we can use it:

        ! ie. this one is the invalid register window.

        ! must establish a safe stack before re-enabling interrupts + traps

        and     %l0, __WINBITS, %l7     ! CWP extracted

        ! no inc/dec here, so no need for special measures for not-8-windows

        mov     1, %l6

        sll     %l6, %l7, %l6           ! 1 << CWP

        rd      %wim, %l5

        cmp     %l5, %l6                ! are they the same?

        bne     1f                      ! No, so the stack is OK as is.

        ! now do by hand an overflow trap, effectively

        mov     %g1, %l7                ! (DELAY SLOT)

        srl     %l5, 1, %l5

        sll     %l6, __WINSIZE-1, %l6

        or      %l6, %l5, %g1           ! new WIM in %g1 so we can get it

                                        ! within the save:

        save                            ! Slip into next window

        mov     %g1, %wim               ! Install the new wim

                                        ! (invalidates current window!)

#ifdef DELAYS_AFTER_WRWIM

        nop

        nop

        nop

#endif

        std     %l0, [%sp + 0 * 4]      ! save L & I registers

        std     %l2, [%sp + 2 * 4]

        std     %l4, [%sp + 4 * 4]

        std     %l6, [%sp + 6 * 4]

        std     %i0, [%sp + 8 * 4]

        std     %i2, [%sp + 10 * 4]

        std     %i4, [%sp + 12 * 4]

        std     %i6, [%sp + 14 * 4]

        restore                         ! Go back to trap window.

        mov     %l7, %g1                ! Restore %g1

1:      ! now save away the regs we must preserve

        sub     %fp, 32 * 4, %sp

#ifdef CYGDBG_HAL_COMMON_INTERRUPTS_SAVE_MINIMUM_CONTEXT

        std     %g0, [%sp + 16 * 4]     ! save G registers

        std     %g2, [%sp + 18 * 4]     ! (set %g0 place to 0 to flag special context)

        std     %g4, [%sp + 20 * 4]

        std     %g6, [%sp + 22 * 4]

#else // not CYGDBG_HAL_COMMON_INTERRUPTS_SAVE_MINIMUM_CONTEXT

        std     %l0, [%sp + 0 * 4]      ! save L & I registers

        std     %l2, [%sp + 2 * 4]

        std     %l4, [%sp + 4 * 4]

        std     %l6, [%sp + 6 * 4]

        std     %i0, [%sp + 8 * 4]

        std     %i2, [%sp + 10 * 4]

        std     %i4, [%sp + 12 * 4]

        std     %i6, [%sp + 14 * 4]

        st      %g1, [%sp + 17 * 4]     ! save G registers

        std     %g2, [%sp + 18 * 4]

        std     %g4, [%sp + 20 * 4]

        std     %g6, [%sp + 22 * 4]

        ! no point whatsoever in saving O registers

        ! and save the CWP in %g0 save place

        st      %l0, [%sp + 16 * 4]

#endif // ! CYGDBG_HAL_COMMON_INTERRUPTS_SAVE_MINIMUM_CONTEXT

        sub     %sp, 24 * 4, %sp        ! fresh frame including

                                        ! arg spill area for callees

        MARKSTACKUSED                   ! kilroy was here

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

        ! we will switch to the interrupt stack unless already running on it

        .extern cyg_interrupt_stack

        .extern cyg_interrupt_stack_base

        set     cyg_interrupt_stack, %g1

        set     cyg_interrupt_stack_base, %g2

        cmp     %sp, %g2                ! below base?

        blu     1f                      ! if so, switch.

        cmp     %sp, %g1                ! below top? (DELAY SLOT)

        blu     2f                      ! if so, DON~T switch.

        nop                             ! (DELAY SLOT)

1:      ! switch to the interrupt stack

        st      %sp, [ %g1 ]            ! there is spare above stack

        sub     %g1, 24 * 4, %sp        ! fresh frame including

                                        ! arg spill area for callees

        MARKSTACKUSED                   ! kilroy was here

2:

        ! continue as before, already in the interrupt stack.

#endif // CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

#ifdef CYGFUN_HAL_COMMON_KERNEL_SUPPORT

        ! Lock the scheduler

        .extern SCHED_LOCK_MANGLED_NAME

        sethi   %hi(SCHED_LOCK_MANGLED_NAME), %l7

        ld      [ %l7 + %lo(SCHED_LOCK_MANGLED_NAME) ], %l6

        add     %l6, 1, %l6

        st      %l6, [ %l7 + %lo(SCHED_LOCK_MANGLED_NAME) ]

#endif

        ! HELP_GDB_WITH_BACKTRACE

        mov     %i7, %l5                ! preserve it in l5

        mov     %l1, %i7                ! bogus return link here

        ! and we must preserve the Y register (multiply/divide auxiliary)

        ! over these calls; we will keep it in %l4 which is otherwise unused.

        rd      %y, %l4

        ! Now we can reenable traps and mask off only lower prio interrupts:

        andn    %l0, 0xf00, %l7         ! clear PIL field

        or      %l7, 0x0e0, %l7         ! and ET (+S,PS)

        sll     %l3, 8, %l6             ! trap number (1-15) into PIL bitfield

        wr      %l7, %l6, %psr          ! and enable!

#ifdef DELAYS_AFTER_WRPSR_SAME_WINDOW

        nop

        nop

        nop

#endif

        ! now call the ISR and so on with the appropriate args:

        ! ie.

        ! isr_retcode = (*(hal_interrupt_handlers[ vector ]))

        !                          ( vector, hal_interrupt_data[ vector ] );

        ! from hal_arch.h

        !// ISR tables

        !CYG_ADDRESS    hal_interrupt_handlers[CYGNUM_HAL_ISR_COUNT];

        !CYG_ADDRWORD   hal_interrupt_data[CYGNUM_HAL_ISR_COUNT];

        !CYG_ADDRESS    hal_interrupt_objects[CYGNUM_HAL_ISR_COUNT];

        mov     %l3, %o0

        sll     %l3, 2, %l3             ! %l3 to a word offset

        sethi   %hi(hal_interrupt_data), %l7

        or      %l7, %lo(hal_interrupt_data), %l7

        ld      [ %l7 + %l3 ], %o1

        sethi   %hi(hal_interrupt_handlers), %l7

        or      %l7, %lo(hal_interrupt_handlers), %l7

        ld      [ %l7 + %l3 ], %l6

        call    %l6

        nop

#ifdef CYGFUN_HAL_COMMON_KERNEL_SUPPORT

        ! We only need to call _interrupt_end() when there is a kernel

        ! present to do any tidying up.

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

        ! now we switch back to the user stack (if we~re at the top

        ! of the interrupt stack).

        or      %l0, 0xfe0, %l7

        wr      %l7, %psr               ! Interrupts all masked, ET

#ifdef DELAYS_AFTER_WRPSR_SAME_WINDOW

        nop

        nop

        nop

#endif

        .extern cyg_interrupt_stack

        set     cyg_interrupt_stack - (24 * 4), %g1

        cmp     %sp, %g1                ! is SP less?

        blu     1f                      ! if so, do not change back

        nop

        ! switch to the thread stack

        ld      [ %g1 + (24 * 4) ], %sp         ! there is spare above stack

1:

#else // CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

        ! First restore the processor interrupt level to that interrupted

        ! (otherwise a task-switch runs at the current PIL) on the assumption

        ! that the ISR dealt with the interrupt source per se, so it is safe

        ! to unmask it, effectively:

        or      %l0, 0x0e0, %l7         ! original PSR and ET (+S,PS)

        wr      %l7, %psr               ! and enable!

#ifdef DELAYS_AFTER_WRPSR_SAME_WINDOW

        nop

        nop

        nop

#endif

#endif // CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

        ! then call interrupt_end( isr_retcode, &intr_object, ®save )

        ! to unlock the scheduler and do any rescheduling that~s needed.

        ! argument 0 (isr_retcode) is already in place in %o0

        sethi   %hi(hal_interrupt_objects), %l7

        or      %l7, %lo(hal_interrupt_objects), %l7

        ld      [ %l7 + %l3 ], %o1

        add     %sp, 24 * 4, %o2        ! saved regset (maybe tiny)

        .extern interrupt_end

        call    interrupt_end

        nop

#endif

        ! restore the Y register having done our callouts to C

        wr      %l4, %y

        ! We can reinstall the original CWP here; even if interrupt_end()

        ! performed a reschedule (ie. yield/resume pair) we will be in the

        ! same window.  The window is preserved by reschedule precisely

        ! because it is impossible atomically to disable traps here without

        ! involving a CWP living in a register for a time when other

        ! interrupts may occur.

        ! disable traps (using the saved psr is fastest way)

        wr      %l0, %psr       ! restores flags, disables traps, and old PIL

#ifdef DELAYS_AFTER_WRPSR_SAME_WINDOW

        nop

        nop

        nop

#endif

        ! HELP_GDB_WITH_BACKTRACE

        mov     %l5, %i7        ! restore (unused) return link

        ! and restore other saved regs

        ! (see CYGDBG_HAL_COMMON_INTERRUPTS_SAVE_MINIMUM_CONTEXT)

        add     %sp, 24 * 4, %sp        ! undo fresh frame

        ld      [%sp + 17 * 4], %g1     ! restore G registers

        ldd     [%sp + 18 * 4], %g2

        ldd     [%sp + 20 * 4], %g4

        ldd     [%sp + 22 * 4], %g6

        ! and do NOT restore any other registers L, I or O

        ! Now test for window underflow here and fix up if needs be.

        !

        ! Why?  interrupt_end() might have yielded us, when only

        ! its own frame was restored; its own return to us caused a

        ! window underflow trap, as would our return to interruptee

        ! unless we deal with it now.

        add     %l0, 1, %l7             ! interruptee~s CWP plus noise

        and     %l7, __WINBITS, %l7     ! CWP only

#if 8 == __WINSIZE

        ! it is in range already

#else   // expect 5 or 6 or 7 windows

        cmp     %l7, __WINSIZE

        bge,a   567f                    ! taken: do delay slot, handle overflow

         mov    0, %l7                  ! only if .ge. above

567:

#endif

        mov     1, %l6

        sll     %l6, %l7, %l6           ! 1 << CWP

        rd      %wim, %l5

        cmp     %l5, %l6                ! are they the same?

        bne     2f                      ! No, so the stack is OK as is.

        ! now do by hand an underflow trap, effectively

        sll     %l5, 1, %l5             ! Rotate wim left

        srl     %l6, __WINSIZE-1, %l6

        wr      %l5, %l6, %wim

#ifdef DELAYS_AFTER_WRWIM

        nop                             ! are these delays needed?

        nop                             ! (following restore uses wim)

        nop

#endif

        restore                         ! Interruptee~s window

        ldd     [%sp + 0 * 4], %l0      ! restore L & I registers

        ldd     [%sp + 2 * 4], %l2

        ldd     [%sp + 4 * 4], %l4

        ldd     [%sp + 6 * 4], %l6

        ldd     [%sp + 8 * 4], %i0

        ldd     [%sp + 10 * 4], %i2

        ldd     [%sp + 12 * 4], %i4

        ldd     [%sp + 14 * 4], %i6

        save                            ! Back to trap window

2:      ! restore the condition codes, PSR and PIL and return from trap.

        wr      %l0, %psr       ! restores flags, disables traps, and old PIL

#ifdef DELAYS_AFTER_WRPSR_SAME_WINDOW

        nop

        nop

        nop

#endif

        jmpl    %l1,  %g0

        rett    %l2

!----------------------------------------------------------------------------

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

! This routine can only be called from a thread stack, maybe

! with interrupts (but not traps) disabled.

! It switches to the interrupt stack then calls back to the

! kernel to execute DSRs.

        .global hal_interrupt_stack_call_pending_DSRs

hal_interrupt_stack_call_pending_DSRs:

        save    %sp, -24 * 4, %sp

        MARKSTACKUSED                   ! kilroy was here

        ! be atomic

        rd      %psr, %l0

        andn    %l0, 0x20, %l1          ! clear ET to disable traps

        wr      %l1, %psr               ! into the PSR

        nop

        nop

        nop

        mov     %sp, %l7                ! save calling stack location

        ! now switch stack to the interrupt stack, plus some headroom

        ! for saving a register set if we are interrupted

        .extern cyg_interrupt_stack

        set     cyg_interrupt_stack - 4 * 24, %sp

        MARKSTACKUSED                   ! kilroy was here

        ! and enable interrupts unconditionally to call the DSRs

        or      %l0, 0x0e0, %l2         ! set ET, S, PS

        andn    %l2, 0xf00, %l2         ! PIL to zero

        wr      %l2, %psr               ! into the PSR

        nop

        nop

        nop

        .extern cyg_interrupt_call_pending_DSRs

        call    cyg_interrupt_call_pending_DSRs

        nop

        mov     %l7, %sp                ! restore calling stack

        wr      %l0, %psr               ! restore interrupt status

        nop

        nop

        nop

        ret

        restore

#endif // CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK

!----------------------------------------------------------------------------

! end of vec_ivsr.S