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

##      context.S

##

##      CalmRISC32 context switch code

##

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

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

## This file is part of eCos, the Embedded Configurable Operating System.

## Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.

##

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## for more details.

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##

## 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,

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## must still be made available in accordance with section (3) of the GNU

## General Public License v2.

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

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

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

##

## Author(s):   msalter

## Contributors: msalter

## Date:        2001-02-12

## Purpose:     CalmRISC32 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_R0        0

#define CYGARC_JMP_BUF_R1        1

#define CYGARC_JMP_BUF_R2        2

#define CYGARC_JMP_BUF_R3        3

#define CYGARC_JMP_BUF_R4        4

#define CYGARC_JMP_BUF_R5        5

#define CYGARC_JMP_BUF_R6        6

#define CYGARC_JMP_BUF_R7        7

#define CYGARC_JMP_BUF_R12       8

#define CYGARC_JMP_BUF_R13       9

#define CYGARC_JMP_BUF_R14      10

#define CYGARC_JMP_BUF_R15      11

#define CYGARC_JMP_BUF_SIZE     48

// 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:

        ld      r8, r0

        ldw     @[r8+0], r0

        ldw     @[r8+4], r1

        ldw     @[r8+8], r2

        ldw     @[r8+12], r3

        ldw     @[r8+16], r4

        ldw     @[r8+20], r5

        ldw     @[r8+24], r6

        ldw     @[r8+28], r7

        ldw     @[r8+32], r12

        ldw     @[r8+36], r13

        ldw     @[r8+40], r14

        ldw     @[r8+44], sp

        jmpd    r14

         ldw    r0, #0

        .globl  hal_longjmp

hal_longjmp:

        ld      r9, r0

        ld      r8, r1

        ldw     sp, @[r9+44]

        ldw     r14, @[r9+40]

        ldw     r13, @[r9+36]

        ldw     r12, @[r9+32]

        ldw     r7, @[r9+28]

        ldw     r6, @[r9+24]

        ldw     r5, @[r9+20]

        ldw     r4, @[r9+16]

        ldw     r3, @[r9+12]

        ldw     r2, @[r9+8]

        ldw     r1, @[r9+4]

        # Value to return is in r8.  If zero, return 1

        ld      r0, r8

        cmp eq  r0, #0

        brf     0f

        ldw     r0, #1

    0:

        jmpd    r14

         nop

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

# end of context.S