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##=============================================================================##

##      context.S

##

##      CalmRISC16 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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## or inline functions from this file, or you compile this file and link it

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#####ECOSGPLCOPYRIGHTEND####

##=============================================================================

#######DESCRIPTIONBEGIN####

##

## Author(s):   msalter

## Contributors: msalter

## Date:        2001-02-12

## Purpose:     CalmRISC16 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 

#------------------------------------------------------------------------------

# hal_thread_switch_context

# Switch thread contexts

# A0 = address of sp of next thread to execute

# A1 = address of sp save location of current thread

        .global hal_thread_switch_context

hal_thread_switch_context:

        // FIXME

        # Now load the destination thread by dropping through

        # to hal_thread_load_context

#------------------------------------------------------------------------------

# hal_thread_load_context

# Load thread context

# A0 = 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:

        // FIXME

#------------------------------------------------------------------------------

# HAL longjmp, setjmp implementations

# hal_setjmp saves only callee save registers into given buffer

# Note: These definitions are repeated in hal_arch.h. If changes are required

# remember to update both sets.

#define CYGARC_JMP_BUF_R4        0

#define CYGARC_JMP_BUF_R5        2

#define CYGARC_JMP_BUF_A12       4

#define CYGARC_JMP_BUF_A13       8

#define CYGARC_JMP_BUF_A14      12

#define CYGARC_JMP_BUF_A15      16

#define CYGARC_JMP_BUF_SIZE     20

// FIXME: The follwing restricts us to using only 32 bit registers

// in jump buffers. If/when we move to a full 64 bit architecture,

// this will need to change, as will the instructions that we use to

// save and restore them.

#define jmpbuf_regsize 4

        .globl  hal_setjmp

hal_setjmp:

        ldw     a8,@[sp+2]      // jmpbuf

        ldw     @[a8+0],r4

        ldw     @[a8+2],r5

        ldw     @[a8+4],a12

        ldw     @[a8+8],a13

        ldw     @[a8+12],a14

        ldw     @[a8+16],a15

        retd

         ld     r0,#0

        .end hal_setjmp

        .globl  hal_longjmp

hal_longjmp:

        ldw     a8,@[sp+2]

        ldw     r0,@[sp+6]

        ldw     r4,@[a8+0]

        ldw     r5,@[a8+2]

        ldw     a12,@[a8+4]

        ldw     a13,@[a8+8]

        ldw     a14,@[a8+12]

        ldw     a15,@[a8+16]

        and     r0,r0

        retd

        incc    r0

        .end hal_longjmp

#------------------------------------------------------------------------------

# end of context.S