frame.inc

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/* MN10300 Microcontroller core system register definitions -*- asm -*-
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#ifndef _ASM_FRAME_INC
#define _ASM_FRAME_INC

#ifndef __ASSEMBLY__
#error not for use in C files
#endif

#ifndef __ASM_OFFSETS_H__
#include <asm/asm-offsets.h>
#endif
#include <asm/thread_info.h>

#define pi break

#define fp a3

###############################################################################
#
# build a stack frame from the registers
# - the caller has subtracted 4 from SP before coming here
#
###############################################################################
.macro SAVE_ALL
    add -4,sp               # next exception frame ptr save area
    movm    [other],(sp)
    mov usp,a1
    mov a1,(sp)             # USP in MOVM[other] dummy slot
    movm    [d2,d3,a2,a3,exreg0,exreg1,exother],(sp)
    mov sp,fp               # FRAME pointer in A3
    add -12,sp              # allow for calls to be made

    # push the exception frame onto the front of the list
    GET_THREAD_INFO a1
    mov (TI_frame,a1),a0
    mov a0,(REG_NEXT,fp)
    mov fp,(TI_frame,a1)

    # disable the FPU inside the kernel
    and ~EPSW_FE,epsw

    # we may be holding current in E2
#ifdef CONFIG_MN10300_CURRENT_IN_E2
    mov (__current),e2
#endif
.endm

###############################################################################
#
# restore the registers from a stack frame
#
###############################################################################
.macro RESTORE_ALL
    # peel back the stack to the calling frame
    # - we need that when returning from interrupts to kernel mode
    GET_THREAD_INFO a0
    mov (TI_frame,a0),fp
    mov fp,sp
    mov (REG_NEXT,fp),d0
    mov d0,(TI_frame,a0)                # userspace has regs->next == 0

#ifndef CONFIG_MN10300_USING_JTAG
    mov (REG_EPSW,fp),d0
    btst    EPSW_T,d0
    beq 99f

    or  EPSW_NMID,epsw
    movhu   (DCR),d1
    or  0x0001, d1
    movhu   d1,(DCR)

99:
#endif
    movm    (sp),[d2,d3,a2,a3,exreg0,exreg1,exother]

    # must restore usp even if returning to kernel space,
    # when CONFIG_PREEMPT is enabled.
    mov (sp),a1             # USP in MOVM[other] dummy slot
    mov a1,usp

    movm    (sp),[other]
    add 8,sp
    rti

.endm


#endif /* _ASM_FRAME_INC */