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// #===========================================================================

// #

// #    context.S

// #

// #    ARM 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.

//

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// for more details.

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// 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

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// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

// #===========================================================================

// ######DESCRIPTIONBEGIN####

// #

// # Author(s):    nickg, gthomas

// # Contributors: nickg, gthomas

// # Date:         1998-09-15

// # Purpose:      ARM context switch code

// # Description:  This file contains implementations of the thread context

// #               switch routines. It also contains the longjmp() and setjmp()

// #               routines.

// #

// #####DESCRIPTIONEND####

// #

// #===========================================================================

#include 

#include "arm.inc"

        .text

// ----------------------------------------------------------------------------

//  function declaration macro (start body in ARM mode)

#ifdef __thumb__

#define FUNC_START_ARM(_name_, _r_)              \

        .code   16                              ;\

        .thumb_func                             ;\

        .globl _name_                           ;\

_name_:                                         ;\

        ldr     _r_,=_name_ ## _ARM             ;\

        bx      _r_                             ;\

        .code   32                              ;\

_name_ ## _ARM:

#else

#define FUNC_START_ARM(_name_, _r_) \

        .globl _name_; \

_name_:

#endif

// ----------------------------------------------------------------------------

//  hal_thread_switch_context

//  Switch thread contexts

//  R0 = address of sp of next thread to execute

//  R1 = address of sp save location of current thread

// Need to save/restore R4..R12, R13 (sp), R14 (lr)

// Note: this is a little wasteful since r0..r3 don't need to be saved.

// They are saved here though so that the information can match the HAL_SavedRegisters

FUNC_START_ARM(hal_thread_switch_context, r2)

        sub     ip,sp,#20               // skip svc_sp, svc_lr, vector, cpsr, and pc

        stmfd   ip!,{sp,lr}

        mov     sp,ip

        stmfd   sp!,{r0-r10,fp,ip}

        mrs     r2,cpsr

        str     r2,[sp,#armreg_cpsr]

        str     sp,[r1]                 // return new stack pointer

#ifdef __thumb__

        b       hal_thread_load_context_ARM // skip mode switch stuff

#endif

        # Now load the destination thread by dropping through

        # to hal_thread_load_context

// ----------------------------------------------------------------------------

//  hal_thread_load_context

//  Load thread context

//  R0 = 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.

FUNC_START_ARM(hal_thread_load_context, r2)

        ldr     fp,[r0]                 // get context to restore

        mrs     r0,cpsr                 // disable IRQ's

        orr     r0,r0,#CPSR_IRQ_DISABLE|CPSR_FIQ_DISABLE

        msr     cpsr,r0

        ldr     r0,[fp,#armreg_cpsr]

        msr     spsr,r0

        ldmfd   fp,{r0-r10,fp,ip,sp,lr}

#ifdef __thumb__

        mrs     r1,spsr                 // r1 is scratch

                                        // [r0 holds initial thread arg]

        msr     cpsr,r1                 // hopefully no mode switch here!

        bx      lr

#else

        movs    pc,lr                   // also restores saved PSR

#endif

// ----------------------------------------------------------------------------

//  HAL longjmp, setjmp implementations

//  hal_setjmp saves only to callee save registers 4-14

//  and lr into buffer supplied in r0[arg0]

FUNC_START_ARM(hal_setjmp, r2)

        stmea   r0,{r4-r14}

        mov     r0,#0

#ifdef __thumb__

        bx      lr

#else

        mov     pc,lr;          # return

#endif

//  hal_longjmp loads state from r0[arg0] and returns

FUNC_START_ARM(hal_longjmp, r2)

        ldmfd   r0,{r4-r14}

        mov     r0,r1;          # return [arg1]

#ifdef __thumb__

        bx      lr

#else

        mov     pc,lr

#endif

// ----------------------------------------------------------------------------

//  end of context.S