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// #===========================================================================
// #
// # context.S
// #
// # ZYLIN context switch code
// #
// #===========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, 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.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 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.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
// #===========================================================================
// ######DESCRIPTIONBEGIN####
// #
// # Author(s): nickg, gthomas
// # Contributors: nickg, gthomas
// # Date: 1998-09-15
// # Purpose: ZYLIN context switch code
// # Description: This file contains implementations of the thread context
// # switch routines. It also contains the longjmp() and setjmp()
// # routines.
// #
// #####DESCRIPTIONEND####
// #
// #===========================================================================
#include <pkgconf/hal.h>
#ifdef CYGPKG_KERNEL // no CDL yet
#include <pkgconf/kernel.h>
#else
# undef CYGFUN_HAL_COMMON_KERNEL_SUPPORT
# undef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK
#endif
#include "zylin.inc"
.text
;; By using a macro, we get multiple breakpoint sites
.macro LOAD_STATE
popsp
; stack pointer now points to beginning of HAL_SavedRegisters
; we now pop the state of the CPU
; this will restore r0-r3
im 0
store
im 4
store
im 8
store
im 12
store
im 16
store
im 20
store
im 24
store
im 28
store
;; restore interrupts
im INTERRUPT_MASK
load
store
.endm
// ----------------------------------------------------------------------------
// hal_thread_switch_context
// Switch thread contexts
.globl hal_thread_switch_context
hal_thread_switch_context:
;; save interrupt state
im INTERRUPT_MASK
load
load
; store current state on stack
im 28
load
im 24
load
im 20
load
im 16
load
im 12
load
im 8
load
im 4
load
im 0
load
;; store pointer to SP in "from" pointer
pushsp
pushsp
im 8+8*4+4+4
add
load
store
;; put pointer to '*to' on stack
pushsp
im 4+8*4+4
add
load
load
LOAD_STATE
poppc ; voila! jump to saved pc
// ----------------------------------------------------------------------------
// hal_thread_load_context
// Load thread context
.globl hal_thread_load_context
hal_thread_load_context:
pushsp
im 4
add
load
load ; pointer to HAL_SavedRegisters on stack
load_state_internal:
LOAD_STATE
poppc ; voila! jump to saved pc
// ----------------------------------------------------------------------------
// HAL longjmp, setjmp implementations
.globl hal_setjmp
hal_setjmp:
.byte 0
.globl hal_longjmp
hal_longjmp:
.byte 0
// ----------------------------------------------------------------------------
// end of context.S
#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK
; push 1 onto stack if we're already switched, 0 otherwise
.macro check_thread_stack
pushsp ; 0xda68
im __interrupt_stack ; 0x241a
lessthan ; => 1
im __interrupt_stack_base
pushsp
lessthan
or
.endm
; push 1 onto stack if we're already switched, 0 otherwise
.macro switch_stack
pushsp
im __interrupt_stack-4
store ; saved stack pointer on interrupt stack.
im __interrupt_stack-4
popsp
; we're now on the interrupt stack
.endm
.macro switch_stack_back
; return to thread stack
popsp
.endm
_zpu_invoke_zpu_interrupt_stack:
im hal_IRQ_handler
call
im 0
load ; return value - source
im _zpu_interrupt_stack
call
im 0
load ; return value - result
; we've got source and ISR result args on the stack
im _zpu_interrupt_thread
call
storesp 0 ; destroy args
storesp 0
poppc
// switch to interrupt stack, invoke interrupt handler, switch back to original stack, enable interrupts
.globl _zpu_interrupt
_zpu_interrupt:
; disable interrupts, we don't nest
im 1
nop
im INTERRUPT_MASK
load
store
; if we're interrupting the DSRs then
; we're already on the interrupt stack
check_thread_stack
impcrel _already_switched
eqbranch
_zpu_interrupt_switch_stack:
switch_stack
im _zpu_invoke_zpu_interrupt_stack
call
switch_stack_back
im .already_switched2
poppc
_already_switched:
im _zpu_invoke_zpu_interrupt_stack
call
.already_switched2:
; turn on interrupts and run on thread stack.
im 0
nop
im INTERRUPT_MASK
load
store ; unmask interrupts
; we're now running on thread stack
im _zpu_interrupt_thread
call
poppc
.globl hal_interrupt_stack_call_pending_DSRs
hal_interrupt_stack_call_pending_DSRs:
; the scheduler is not running, so only interrupts
; could have switched stacks at this point and
; since we're running, interrupts are not
switch_stack
im cyg_interrupt_call_pending_DSRs
call
switch_stack_back
; back on thread stack
poppc
// Runtime stack used during all interrupt processing
#ifndef CYGNUM_HAL_COMMON_INTERRUPTS_STACK_SIZE
#define CYGNUM_HAL_COMMON_INTERRUPTS_STACK_SIZE 4096
#endif
.bss
.balign 4,0
.global cyg_interrupt_stack_base
cyg_interrupt_stack_base:
__interrupt_stack_base:
.rept CYGNUM_HAL_COMMON_INTERRUPTS_STACK_SIZE
.byte 0
.endr
.balign 4,0
.global cyg_interrupt_stack
cyg_interrupt_stack:
__interrupt_stack:
#endif
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