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##=============================================================================
##
## context.S
##
## MN10300 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
## Contributors: nickg
## Date: 1998-04-27
## Purpose: MN10300 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>
#include <cyg/hal/arch.inc>
#------------------------------------------------------------------------------
# hal_thread_switch_context
# Switch thread contexts
# D0 = address of sp of next thread to execute
# D1 = address of sp save location of current thread
.global _hal_thread_switch_context
_hal_thread_switch_context:
add -8,sp # space for SP and PSW
mov d2,a0 # move d2->a0 since PSW can only be
# saved to a data register
hal_cpu_get_psw d2 # save PSW to d2
mov d2,(4,sp) # store in stack loc
mov a0,d2 # retrieve old d2 value
hal_cpu_save_all # save entire register set
mov d1,a2 # move save loc addr to A2
mov sp,(0,a2) # store SP in save location
# Now load the destination thread by dropping through
# to hal_thread_load_context
#------------------------------------------------------------------------------
# hal_thread_load_context
# Load thread context
# D0 = address of sp of next thread to execute
# Note that this function is also the second half of hal_thread_switch_context
# and is simply dropped into from it.
.global _hal_thread_load_context
_hal_thread_load_context:
mov d0,a2 # move next sp loc to a2
mov (0,a2),sp # load SP with new value
hal_cpu_load_all # load whole register set
mov (4,sp),d1 # retrieve saved PSW
hal_cpu_set_psw d1 # and restore it
add 8,sp # skip saved SP and PSW
ret [],0 # and return
##-----------------------------------------------------------------------------
## HAL longjmp(), setjmp() implementations
## These implementations omit the usual movm [d2,d3,a2,a3],(sp)
## Which is the first instruction of all C compiled functions.
## Note: These definitions are repeated in hal_arch.h. If changes are required
## remember to update both sets.
#define CYGARC_JMP_BUF_SP 0
#define CYGARC_JMP_BUF_D2 1
#define CYGARC_JMP_BUF_D3 2
#define CYGARC_JMP_BUF_A2 3
#define CYGARC_JMP_BUF_A3 4
#define CYGARC_JMP_BUF_LR 5
#define CYGARC_JMP_BUF_SIZE 6
# This just preserves the callee save registers
# namely a2,a3,d2,d3
# setjmp cannot use movm to do this as we need to keep
# the sp underneath all live data at all times.
.globl _hal_setjmp
_hal_setjmp: # d0=env
mov d0,a0 # env
mov d2,(CYGARC_JMP_BUF_D2*4,a0)
mov d3,(CYGARC_JMP_BUF_D3*4,a0)
mov a2,(CYGARC_JMP_BUF_A2*4,a0)
mov a3,(CYGARC_JMP_BUF_A3*4,a0)
mov mdr,d1 # link saved by call (also in (0,sp))
mov d1,(CYGARC_JMP_BUF_LR*4,a0)
mov sp,a1
mov a1,(CYGARC_JMP_BUF_SP*4,a0) # a1==(caller''s sp)
clr d0 # return 0
ret [],0
# longjmp returns to caller of setjmp
# after restoring callee save registers
.globl _hal_longjmp
_hal_longjmp:
mov d0,a0
mov (CYGARC_JMP_BUF_D2*4,a0),d2
mov (CYGARC_JMP_BUF_D3*4,a0),d3
mov (CYGARC_JMP_BUF_A2*4,a0),a2
mov (CYGARC_JMP_BUF_A3*4,a0),a3
mov (CYGARC_JMP_BUF_LR*4,a0),d0
## mov d0,mdr
mov (CYGARC_JMP_BUF_SP*4,a0),a1 # stashed (caller''s sp)
mov a1,sp
mov d0,(0,sp) # put link on stack
mov d1,d0 # return arg1
ret [],0 # this ignores (0,sp) and does pc=mdr
#------------------------------------------------------------------------------
# end of context.S
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