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/*===========================================================================
//
// vec_xvsr.S
//
// SPARC vectors: exception vector service routine
//
//===========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later
// version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with eCos; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
// this file does not by itself cause the resulting work to be covered by
// the GNU General Public License. However the source code for this file
// must still be made available in accordance with section (3) of the GNU
// General Public License v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): hmt
// Contributors: hmt
// Date: 1999-02-20
// Purpose: SPARC vector code
// Description: see vectors.S; this is the default vector service routine
// for exceptions.
//
//####DESCRIPTIONEND####
//
//=========================================================================*/
!-----------------------------------------------------------------------------
// .file "vec_xvsr.S"
!----------------------------------------------------------------------------
#include <pkgconf/system.h>
#include <pkgconf/hal.h>
#ifdef CYGPKG_KERNEL
# include <pkgconf/kernel.h>
#endif
!------------------------------------------------------------------------
#include <cyg/hal/vectors.h>
#define DELAYS_AFTER_WRPSR_SAME_WINDOW
#define DELAYS_AFTER_WRWIM
!------------------------------------------------------------------------
.text
!---------------------------------------------------------------------------
! default exception handler VSR, which calls the appropriate ISR after
! interrupt masking - much the same as the interrupt VSR but does not lock
! scheduler or call interrupt_end().
.global hal_default_exception_vsr
hal_default_exception_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 (16-25 for traps)
! 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
! save a maximal context regardless: see also
! 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]
sub %sp, 24 * 4, %sp ! fresh frame including
! arg spill area for callees
! do not lock the scheduler
! HELP_GDB_WITH_BACKTRACE
mov %i7, %l5 ! preserve it JIC
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 (preserving interrupt level)
or %l0, 0x0e0, %l7 ! set ET (+S,PS), preserve PIL
wr %l7, %psr ! and enable!
#ifdef DELAYS_AFTER_WRPSR_SAME_WINDOW
nop
nop
nop
#endif
! now call the XSR and so on with the appropriate args:
! ie.
! isr_retcode = (*(hal_interrupt_handlers[ vector ]))
! ( vector, hal_interrupt_data[ vector ], stackp );
! 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 ! data
add %sp, 24 * 4, %o2 ! stackpointer of saved regset
sethi %hi(hal_interrupt_handlers), %l7
or %l7, %lo(hal_interrupt_handlers), %l7
ld [ %l7 + %l3 ], %l6
call %l6
nop
! do not call _interrupt_end()
! 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, same 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
add %sp, 24 * 4, %sp ! undo fresh frame
! restore a maximal context regardless: see also
! CYGDBG_HAL_COMMON_INTERRUPTS_SAVE_MINIMUM_CONTEXT
ldd [%sp + 0 * 4], %l0 ! restore L & I registers
ldd [%sp + 2 * 4], %l2 ! to support the handler
ldd [%sp + 4 * 4], %l4 ! having messed with them.
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
ld [%sp + 17 * 4], %g1 ! and G registers
ldd [%sp + 18 * 4], %g2
ldd [%sp + 20 * 4], %g4
ldd [%sp + 22 * 4], %g6
! no point whatsoever in loading back O registers.
! 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
! end of vec_xvsr.S
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