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

##

##      context.S

##

##      H8/300 context switch code

##

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

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

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

##

## Author(s):   yoshinori sato

## Contributors:        yoshinori sato

## Date:        2002-02-17

## Purpose:     H8/300 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 

#include 

        .h8300h

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

# hal_thread_switch_context

# Switch thread contexts

# D0 = address of sp of next thread to execute

# D1 = address of sp save location of current thread

        .global CYG_LABEL_DEFN(hal_thread_switch_context)

CYG_LABEL_DEFN(hal_thread_switch_context):

        hal_cpu_save_all

        mov.l   sp,@er1

        # Now load the destination thread by dropping through

        # to hal_thread_load_context

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

# hal_thread_load_context

# Load thread context

# D0 = 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 CYG_LABEL_DEFN(hal_thread_load_context)

CYG_LABEL_DEFN(hal_thread_load_context):

        mov.l   @er0,sp

        hal_cpu_load_all

        rts

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

## HAL longjmp(), setjmp() implementations

## These implementations omit the usual movm [d2,d3,a2,a3],(sp)

## Which is the first instruction of all C compiled functions.

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

## remember to update both sets.

#define CYGARC_JMP_BUF_SP        0

#define CYGARC_JMP_BUF_ER3       1

#define CYGARC_JMP_BUF_ER4       2

#define CYGARC_JMP_BUF_ER5       3

#define CYGARC_JMP_BUF_ER6       4

#define CYGARC_JMP_BUF_PC        5

#define CYGARC_JMP_BUF_SIZE      6

        # This just preserves the callee save registers

        # namely a2,a3,d2,d3

        # setjmp cannot use movm to do this as we need to keep

        # the sp underneath all live data at all times.

        .globl CYG_LABEL_DEFN(hal_setjmp)

CYG_LABEL_DEFN(hal_setjmp):                              ; er0=env

        mov.l   er3,@(CYGARC_JMP_BUF_ER3*4,er0)

        mov.l   er4,@(CYGARC_JMP_BUF_ER4*4,er0)

        mov.l   er5,@(CYGARC_JMP_BUF_ER5*4,er0)

        mov.l   er6,@(CYGARC_JMP_BUF_ER6*4,er0)

        mov.l   @sp,er1

        mov.l   er1,@(CYGARC_JMP_BUF_PC*4,er0)

        mov     sp,er1

        mov     er1,@(CYGARC_JMP_BUF_SP*4,er0)

        sub.l   er0,er0

        rts

        # longjmp returns to caller of setjmp

        # after restoring callee save registers

        .globl CYG_LABEL_DEFN(hal_longjmp)

CYG_LABEL_DEFN(hal_longjmp):

        mov.l   @(CYGARC_JMP_BUF_ER3*4,er0),er3

        mov.l   @(CYGARC_JMP_BUF_ER4*4,er0),er4

        mov.l   @(CYGARC_JMP_BUF_ER5*4,er0),er5

        mov.l   @(CYGARC_JMP_BUF_ER6*4,er0),er6

        mov.l   @(CYGARC_JMP_BUF_PC*4,er0),er2

        mov.l   @(CYGARC_JMP_BUF_SP*4,er0),sp

        mov.l   er2,@sp

        mov.l   er1,er0

        rts

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

# end of context.S