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|
|=============================================================================
|
| context.S
|
| ColdFire architecture context switch code
|
|=============================================================================
| ####ECOSGPLCOPYRIGHTBEGIN####
| -------------------------------------------
| This file is part of eCos, the Embedded Configurable Operating System.
| Copyright (C) 1998, 1999, 2000, 2001, 2002, 2006 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): Enrico Piria
| Contributors:
| Date: 2005-25-06
| Purpose: 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/cf_offsets.inc>
#include <cyg/hal/arch.inc>
| ----------------------------------------------------------------------------
| hal_thread_switch_context - Switch between two threads
|
| externC void hal_thread_switch_context(CYG_ADDRESS to, CYG_ADDRESS from)
|
| INPUT:
| 0(%sp) : return address
| 4(%sp) : to - address of sp of next thread to execute
| 8(%sp) : from - address of sp save location of current thread
|
| OUTPUT:
| None
|
| RETURN VALUE:
| None
|
| d0, d1, a0, a1 are ours to abuse. Other registers are not touched.
FUNC_START(hal_thread_switch_context)
ctx_save_registers
| Read to and from parameters from the stack
move.l CYGARC_CF_CONTEXT_SIZE+4(%sp),%a0
move.l CYGARC_CF_CONTEXT_SIZE+8(%sp),%a1
| Store this thread's current stack pointer to *from
move.l %sp,(%a1)
| Load the stack pointer for the next thread from *to
move.l (%a0),%sp
ctx_restore_registers
| Return to caller
rts
| ----------------------------------------------------------------------------
| hal_thread_load_context - Load thread context
|
| externC void hal_thread_load_context(CYG_ADDRESS to)
|
| INPUT:
| 4(%sp) : to - address of sp of next thread to execute
|
| OUTPUT:
| None
|
| RETURN VALUE:
| None
|
| d0, d1, a0, a1 are ours to abuse.
FUNC_START(hal_thread_load_context)
| Read the to parameter from the stack and switch to that stack
| pointer
move.l 4(%sp),%a0
move.l (%a0),%sp
| Load all of the preserved registers from the stack
movem.l CYGARC_CFREG_DREGS(%sp),%d0-%d7
movem.l CYGARC_CFREG_AREGS(%sp),%a0-%a6
| Starting SR
move.w CYGARC_CF_SR(%sp), %d0
move.w %d0,%sr
| Deallocate context frame
lea CYGARC_CF_CONTEXT_SIZE(%sp),%sp
| Return
rts
| ----------------------------------------------------------------------------
| The following routines are based on the hal_jmp_buf structure layout, defined
| in hal_arch.h
| ----------------------------------------------------------------------------
| hal_setjmp - setjmp for the ColdFire architecture
|
| externC int hal_setjmp(hal_jmp_buf env)
|
| INPUT:
| 0(%sp) : return address
| 4(%sp) : env - address of a hal_jmp_buf structure
|
| OUTPUT:
| None
|
| RETURN VALUE:
| This routine always returns zero in d0.l.
|
| d0, d1, a0, a1 are ours to abuse.
FUNC_START(hal_setjmp)
| Get a pointer to the register buffer
move.l 4(%sp),%a0
| Store all of the preserved registers
movem.l %d2-%d7,CYGARC_JMPBUF_REG_D2(%a0)
movem.l %a2-%a6,CYGARC_JMPBUF_REG_A2(%a0)
#ifdef CYGHWR_HAL_COLDFIRE_MAC
| Store MAC registers
| Store MACSR register
move.l %macsr,%d0
move.l %d0,CYGARC_JMPBUF_REG_MACSR(%a0)
| Switch to integer mode. This allows to save the contents of ACC
| without rounding
and.l #0x000000df,%d0
move.l %d0,%macsr
| Store ACC register
move.l %acc,%d0
move.l %d0,CYGARC_JMPBUF_REG_MACC(%a0)
| Store MASK register
move.l %mask,%d0
move.l %d0,CYGARC_JMPBUF_REG_MASK(%a0)
#endif
| Store the stack pointer
move.l %sp,CYGARC_JMPBUF_REG_SP(%a0)
| Store the return address into the structure
move.l (%sp),CYGARC_JMPBUF_REG_PC(%a0)
| Load a zero return value
clr.l %d0
| Return
rts
| ----------------------------------------------------------------------------
| hal_longjmp - longjmp for the ColdFire architecture
|
| externC void hal_longjmp(hal_jmp_buf env, int val)
|
| INPUT:
| 0(%sp): return address
| 4(%sp): env - address of a hal_jmp_buf structure
| 8(%sp): val - the non-zero value to return
|
| OUTPUT:
| None
|
| RETURN VALUE:
| This routine always returns the value from the val parameter in d0.l
| and to the location of the PC in the env structure.
FUNC_START(hal_longjmp)
| Load the return value parameter
move.l 8(%sp),%d0
| Get a pointer to the buffer to read our state from
move.l 4(%sp),%a0
| Load all of the preserved registers
movem.l CYGARC_JMPBUF_REG_D2(%a0),%d2-%d7
movem.l CYGARC_JMPBUF_REG_A2(%a0),%a2-%a6
#ifdef CYGHWR_HAL_COLDFIRE_MAC
| Load MAC registers
| Load MACSR register
move.l CYGARC_JMPBUF_REG_MACSR(%a0),%d1
move.l %d1,%macsr
| Load ACC register
move.l CYGARC_JMPBUF_REG_MACC(%a0),%d1
move.l %d1,%acc
| Load MASK register
move.l CYGARC_JMPBUF_REG_MASK(%a0),%d1
move.l %d1,%mask
#endif
| Load the stack pointer
move.l CYGARC_JMPBUF_REG_SP(%a0),%sp
| Load return address and store it on stack
move.l CYGARC_JMPBUF_REG_PC(%a0),(%sp)
| Return to caller
rts
|
