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

##

##      context.S

##

##      SH context switch code

##

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

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

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

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

##

## Author(s):   jskov

## Contributors:jskov

## Date:        1999-05-01

## Purpose:     SH 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 

#include            // CYG_LABEL_DEFN

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

# Register allocation for the Hitachi calling convention:

#

#       r0              arg return

#       r1..r3          scratch

#       r4..r7          args in

#       r8..r13         call saved

#       r14             frame pointer/call saved

#       r15             stack pointer

#       ap              arg pointer (doesn''t really exist, always eliminated)

#       pr              subroutine return address

#       t               t bit

#       mach            multiply/accumulate result, high part

#       macl            multiply/accumulate result, low part.

#       fpul            fp/int communication register

#       rap             return address pointer register

#       fr0             fp arg return

#       fr1..fr3        scratch floating point registers

#       fr4..fr11       fp args in

#       fr12..fr15      call saved floating point registers

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

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

# hal_thread_switch_context

# Switch thread contexts

# R4 = address of sp of next thread to execute

# R5 = address of sp save location of current thread

# Need to save r8-r13, r14 (fp), r15 (sp), pr, mach, macl

FUNC_START(hal_thread_switch_context)

        mov     r15, r0                 ! R0 = saved stack pointer

        sts.l   pr,@-r15                ! save caller in PC slot so it looks

                                        ! sensible when GDB examines it

        stc     sr,r1

        mov.l   r1,@-r15

        sts.l   pr,@-r15                ! return address

        sts.l   macl,@-r15              ! macl

        sts.l   mach,@-r15              ! mach

        mov.l   r0,@-r15                ! saved r15 (entry sp)

        mov.l   r14,@-r15               ! r14-r0

        mov.l   r13,@-r15

        mov.l   r12,@-r15

        mov.l   r11,@-r15

        mov.l   r10,@-r15

        mov.l   r9,@-r15

        mov.l   r8,@-r15

        mov.l   r7,@-r15

        mov.l   r6,@-r15

        mov.l   r5,@-r15

        mov.l   r4,@-r15

        mov.l   r3,@-r15

        mov.l   r2,@-r15

        mov.l   r1,@-r15

        mov.l   r0,@-r15

        mov.l   r15,@r5                 ! save SP into save location

        # Now load the destination thread by dropping through

        # to hal_thread_load_context

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

# hal_thread_load_context

# Load thread context

# R4 = 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(hal_thread_load_context)

        mov.l   @r4,r0

        add     #4+4,r0                 ! skip r0 and r1

        !mov.l   @r0+,r0

        !mov.l   @r0+,r1

        mov.l   @r0+,r2

        mov.l   @r0+,r3

        mov.l   @r0+,r4

        mov.l   @r0+,r5

        mov.l   @r0+,r6

        mov.l   @r0+,r7

        mov.l   @r0+,r8

        mov.l   @r0+,r9

        mov.l   @r0+,r10

        mov.l   @r0+,r11

        mov.l   @r0+,r12

        mov.l   @r0+,r13

        mov.l   @r0+,r14

        mov.l   @r0+,r3                 ! New SP.

        lds.l   @r0+,mach               ! mach

        lds.l   @r0+,macl               ! macl

        lds.l   @r0+,pr                 ! pr

        mov     r3,r15                  ! update stack pointer

        mov.l   @r0+,r2                 ! SR

        hal_cpu_int_merge r2,r0,r1      ! restore interrupt state

        rts                             ! and return

         nop

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

# HAL longjmp, setjmp implementations

# hal_setjmp saves only to callee save registers r8-r13, r14(fp), r15(sp)

# and pr into buffer supplied in r4[arg0]

FUNC_START(hal_setjmp)

        mov.l   r15,@(CYGARC_JMPBUF_SP,r4)

        sts     pr,r0

        mov.l   r0,@(CYGARC_JMPBUF_PR,r4)

        mov.l   r8,@(CYGARC_JMPBUF_R8,r4)

        mov.l   r9,@(CYGARC_JMPBUF_R9,r4)

        mov.l   r10,@(CYGARC_JMPBUF_R10,r4)

        mov.l   r11,@(CYGARC_JMPBUF_R11,r4)

        mov.l   r12,@(CYGARC_JMPBUF_R12,r4)

        mov.l   r13,@(CYGARC_JMPBUF_R13,r4)

        mov.l   r14,@(CYGARC_JMPBUF_R14,r4)

        mov    #0,r0            ! return 0

        rts

         nop

# hal_longjmp loads state from r4[arg0] and returns

# argument supplied in r5[arg1]

FUNC_START(hal_longjmp)

        mov.l   @(CYGARC_JMPBUF_SP,r4),r15

        mov.l   @(CYGARC_JMPBUF_PR,r4),r0

        lds     r0,pr

        mov.l   @(CYGARC_JMPBUF_R8,r4),r8

        mov.l   @(CYGARC_JMPBUF_R9,r4),r9

        mov.l   @(CYGARC_JMPBUF_R10,r4),r10

        mov.l   @(CYGARC_JMPBUF_R11,r4),r11

        mov.l   @(CYGARC_JMPBUF_R12,r4),r12

        mov.l   @(CYGARC_JMPBUF_R13,r4),r13

        mov.l   @(CYGARC_JMPBUF_R14,r4),r14

        mov     r5,r0

        rts

         nop

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

# end of context.S