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/*=============================================================================

//

//      icontext.c

//

//      SPARClite HAL context init function

//

//=============================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

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

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

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 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

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

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

//####ECOSGPLCOPYRIGHTEND####

//=============================================================================

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

//

// Author(s):   hmt

// Contributors:        hmt

// Date:        1998-12-14

// Purpose:     HAL context initialization function

// Description: Initialize a HAL context for SPARClite; this is in C and out

//              of line because there is too much of it for a simple macro.

//

//####DESCRIPTIONEND####

//

//===========================================================================*/

#include <pkgconf/hal.h>

#include <cyg/hal/hal_arch.h>           // HAL header

#include <cyg/infra/cyg_type.h>

#include <cyg/hal/vectors.h>            // SAVE_REGS_SIZE, __WINSIZE, ...

/*---------------------------------------------------------------------------*/

/* We lay out the stack in the manner that the PCS demands:

 *        frame pointer -----> [top of stack]

 *                             Argument spill area (6 words)

 *                             Return Arg pointer

 *                             Initial saved register window (i[8], l[8])

 *                                for use by program when it starts

 *                             [rest of] saved register object (various)

 *        stack pointer -----> saved register window (i[8], l[8])

 *                                to allow us to be interrupted.

 *

 * ie.    frame pointer ->

 *                          struct HAL_FrameStructure

 *        stack pointer ->  struct HAL_SavedRegisters

 *

 * and when the context "resumes" sp is incremented by 40 * 4, the size of

 * a  _struct HAL_SavedRegisters_  which points it at the extant but unused

 *  _struct HAL_FrameStructure_  as the PCS requires.  The frame pointer is

 * left pointing off the top of stack.

 *

 *

 * Thus the stack is the same if created from an already executing context:

 *

 *        frame pointer ----->

 *                             [temporaries and locals]

 *                             [more arguments]

 *                             Argument spill area (6 words)

 *                             Return Arg pointer

 *        [sp at entry]------> Previous saved register window (i[8], l[8])

 *                                for use by program when it starts

 *                             [rest of] saved register object (various)

 *        stack pointer -----> saved register window (i[8], l[8])

 *                                to allow us to be interrupted.

 */

CYG_ADDRESS

hal_thread_init_context(  CYG_WORD sparg,

                          CYG_WORD thread,

                          CYG_WORD entry,

                          CYG_WORD id )

{

    register CYG_WORD fp = sparg;

    register CYG_WORD sp = 0;

    register HAL_SavedRegisters *regs;

    register HAL_FrameStructure *frame;

    int i;

    if ( 0 == (id & 0xffff0000) )

        id <<= 16;

    fp &= ~15;                          // round down to double alignment

    frame = (HAL_FrameStructure *)(

        fp - sizeof( HAL_FrameStructure ) );

    regs = (HAL_SavedRegisters *)(

        ((CYG_WORD)frame) - sizeof(HAL_SavedRegisters) );

    sp = (CYG_WORD)regs;

    for ( i = 0; i < 6; i++ ) {

        frame->spill_args[i] = id | 0xa0 | i;

    }

    frame->composite_return_ptr = 0;

    for ( i = 0; i < 8; i++ ) {

        frame->li.i[i]   = id | ( 56 + i );

        frame->li.l[i]   = id | ( 48 + i );

        regs ->li.i[i]   = id | ( 24 + i );

        regs ->li.l[i]   = id | ( 16 + i );

        regs ->o[i]      = id | (  8 + i );

        regs ->g[i]      = id | (      i );

    }

    // first terminate the linked list on the stack in the initial

    // (already saved) register window:

    frame->li.i[6] = regs->li.i[6] = (cyg_uint32)fp; // frame pointer

    frame->li.i[7] = regs->li.i[7] = (cyg_uint32)0;  // no ret addr here

    // and set up other saved regs as if called from just before

    // the entry point:

    regs->o[7] = (entry - 8);

    regs->o[6] = sp;

    // this is the argument that the entry point is called with

    regs->o[0] = thread;

    // this is the initial CWP and interrupt state; CWP is quite arbitrary

    // really, the WIM is set up accordingly in hal_thread_load_context().

    regs->g[0] = 0x0e0 + __WIN_INIT; // PIL zero, ET, S, PS and CWP set.

    return (CYG_ADDRESS)sp;

}

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

//#define THREAD_DEBUG_SERIAL_VERBOSE

#ifdef THREAD_DEBUG_SERIAL_VERBOSE         // NOT INCLUDED

// This is unpleasant to try to debug, because these routines are called

// WHEN THE PROGRAM IS NOT RUNNING from the CygMon's GDB stubs - so you

// can't use any normal output: these little routines use the serial

// line directly, so are best used when debugging via Ethernet, so you

// just have a separate output stream to read.  Nasty...

#include <cyg/hal/hal_diag.h>

#undef  HAL_DIAG_WRITE_CHAR

#define HAL_DIAG_WRITE_CHAR(_c_) CYG_MACRO_START                    \

    SLEB_LED = (_c_);                                               \

    HAL_DIAG_WRITE_CHAR_DIRECT( _c_ );                              \

CYG_MACRO_END

static void swritec( char c )

{

    HAL_DIAG_WRITE_CHAR( c );

}

static void swrites( char *s )

{

    char c;

    while ( 0 != (c = *s++) )

        HAL_DIAG_WRITE_CHAR( c );

}

static void swritex( cyg_uint32 x )

{

    int i;

    swrites( "0x" );

    for ( i = 28; i >= 0; i-= 4 ) {

        char c = "0123456789abcdef"[ 0xf & (x >> i) ];

        HAL_DIAG_WRITE_CHAR( c );

    }

}

#define newline() swrites( "\n\r" )

static void x8( char *s, unsigned long *xp )

{

    int i;

    for ( i = 0; i < 8; i++ ) {

        swrites( s );

        swritec( '0' + i );

        swrites( " = " );

        swritex( xp[i] );

        if ( 3 == (i & 3) )

            newline();

        else

            swrites( "    " );

    }

}

#endif // THREAD_DEBUG_SERIAL_VERBOSE ... NOT INCLUDED

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

// Routines in icontext.c used here because they're quite large for

// the SPARClite (note param order); these are used in talking to GDB.

enum regnames {G0 = 0, G1, G2, G3, G4, G5, G6, G7,

               O0, O1, O2, O3, O4, O5, SP, O7,

               L0, L1, L2, L3, L4, L5, L6, L7,

               I0, I1, I2, I3, I4, I5, FP, I7,

               F0, F1, F2, F3, F4, F5, F6, F7,

               F8, F9, F10, F11, F12, F13, F14, F15,

               F16, F17, F18, F19, F20, F21, F22, F23,

               F24, F25, F26, F27, F28, F29, F30, F31,

               Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR};

typedef unsigned long target_register_t;

void

cyg_hal_sparc_get_gdb_regs( void *gdb_regset,

                            HAL_SavedRegisters *eCos_regset )

{

    target_register_t *gdb = (target_register_t *)gdb_regset;

    int reg;

    cyg_uint32 scratch = 0;

    cyg_uint32 *sptrap;

    HAL_SavedWindow *trapli, *ctxli;

    if ( 0 == eCos_regset->g[0]             ||

         0xc0 == (0xe0 & eCos_regset->g[0])    ) {

        // Then it's an interrupt stack saved state:

        // (either minimal, or a saved PSR with traps disabled)

        // The saved register set is pretty minimal, so we have to grub

        // around in the stack to find out some truth...

        sptrap = (cyg_uint32 *)eCos_regset; // point to the IL save area for

        sptrap -= 24;                   // the trap handler, for PC, NPC

        trapli = (HAL_SavedWindow *)sptrap; // Get at those regs

        ctxli = (HAL_SavedWindow *)(trapli->i[6]); // (the frame pointer)

                                        // and get at the interruptee's regs

        // Pick up interruptee's registers from all over the stack:

        for ( reg = 0; reg < 8 ; reg++ ) {

            gdb[ G0 + reg ] = eCos_regset->g[reg];

            gdb[ O0 + reg ] = trapli->i[reg];

            gdb[ L0 + reg ] = ctxli->l[reg];

            gdb[ I0 + reg ] = ctxli->i[reg];

        }

        // Clear out G0 which is always 0 (but abused in eCos_regset)

        // and the FP regs which we do not have:

        gdb[ G0 ] = 0;

        for ( reg = F0; reg <= F31; reg++ )

            gdb[ reg ] = 0;

        // In the save context _of the trap handler_ registers are as follows:

        // %l0 = psr (with this CWP/window-level in it)

        // %l1 = pc

        // %l2 = npc

        // %l3 = vector number (1-15 for interrupts)

        // %l4 = Y register preserved

        gdb[ Y ]    = trapli->l[4];

        scratch = trapli->l[0];         // the PSR in the trap handler

#if 8 == __WINSIZE

        scratch++;                      // back to interupted thread's window

        scratch &=~ 0x38;               // clear ET and any __WINSIZE overflow

        gdb[ PSR ]  = scratch;

        gdb[ WIM ]  = 1 << ((__WINBITS & (1 + scratch)));

#else  // 6 or 7 windows only

        reg = (int)(scratch & __WINBITS);

        scratch &=~ (__WINBITS_MAXIMAL | 0x20); // clear ET and  CWP

        if ( __WINSIZE <= ++reg ) reg = 0; // back to intr'd window

        gdb[ PSR ]  = scratch | reg;

        if ( __WINSIZE <= ++reg ) reg = 0; // good index for WIM

        gdb[ WIM ]  = 1 << reg;

#endif // __WINSIZE

        // Read _a_ TBR value and ignore the current trap details:

        asm volatile ( "rd %%tbr, %0" : "=r"(scratch) : );

        gdb[ TBR ]  = (scratch &~ 0xfff);

        gdb[ PC ]   = trapli->l[1];

        gdb[ NPC ]  = trapli->l[2];

        gdb[ FPSR ] = 0;

        gdb[ CPSR ] = 0;

#ifdef THREAD_DEBUG_SERIAL_VERBOSE

        newline();

        swrites( "-----------------------------------------------------" ); newline();

        swrites( "-------------- INTERRUPT STACK GET ------------------" ); newline();

        swrites( "eCos regset at " ); swritex( eCos_regset ); newline();

        swrites( "        trapli " ); swritex( trapli      ); newline();

        swrites( "         ctxli " ); swritex(  ctxli      ); newline();

        x8( "global ", &(gdb[G0]) );

        x8( "    in ", &(gdb[I0]) );

        x8( " local ", &(gdb[L0]) );

        x8( "   out ", &(gdb[O0]) );

        swrites( "gdb  PC = " ); swritex( gdb[  PC ] ); newline();

        swrites( "gdb NPC = " ); swritex( gdb[ NPC ] ); newline();

        swrites( "gdb PSR = " ); swritex( gdb[ PSR ] ); newline();

#endif

    }

    else {

        // It's a synchronous context switch that led to this object.

        // Pick up interruptee's registers from the saved context:

        for ( reg = 0; reg < 8 ; reg++ ) {

#ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM

            gdb[ G0 + reg ] = 0;

            gdb[ O0 + reg ] = 0;

#else

            gdb[ G0 + reg ] = eCos_regset->g[reg];

            gdb[ O0 + reg ] = eCos_regset->o[reg];

#endif

            gdb[ L0 + reg ] = eCos_regset->li.l[reg];

            gdb[ I0 + reg ] = eCos_regset->li.i[reg];

        }

#ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM

        // Set up the stack pointer by arithmetic and the return address

        gdb[ SP ] = ((cyg_uint32)(eCos_regset));

        gdb[ O7 ] = eCos_regset->o[ 7 ];

#else

        // Clear out G0 which is always 0 (but abused in eCos_regset)

        gdb[ G0 ] = 0;

#endif

        // and clear the FP regs which we do not have:

        for ( reg = F0; reg <= F31; reg++ )

            gdb[ reg ] = 0;

        gdb[ Y ]    = 0;                // it's not preserved.

        scratch = eCos_regset->g[ 0 ];  // the PSR in the saved context

        gdb[ PSR ]  = scratch;          // return it verbatim.

#if 8 == __WINSIZE

        gdb[ WIM ]  = 1 << ((__WINBITS & (1 + scratch)));

#else  // 6 or 7 windows only

        reg = (int)(scratch & __WINBITS);

        if ( __WINSIZE <= ++reg ) reg = 0; // good index for WIM

        gdb[ WIM ]  = 1 << reg;

#endif // __WINSIZE

        // Read _a_ TBR value and ignore the current trap details:

        asm volatile ( "rd %%tbr, %0" : "=r"(scratch) : );

        gdb[ TBR ]  = (scratch &~ 0xfff);

        gdb[ PC ]   = eCos_regset->o[ 7 ]; // the return address

        gdb[ NPC ]  = 4 + gdb[ PC ];

        gdb[ FPSR ] = 0;

        gdb[ CPSR ] = 0;

#ifdef THREAD_DEBUG_SERIAL_VERBOSE

        newline();

        swrites( "-----------------------------------------------------" ); newline();

        swrites( "-------------- SYNCHRONOUS SWITCH GET----------------" ); newline();

        swrites( "eCos regset at " ); swritex( eCos_regset ); newline();

        x8( "global ", &(gdb[G0]) );

        x8( "    in ", &(gdb[I0]) );

        x8( " local ", &(gdb[L0]) );

        x8( "   out ", &(gdb[O0]) );

        swrites( "gdb  PC = " ); swritex( gdb[  PC ] ); newline();

        swrites( "gdb NPC = " ); swritex( gdb[ NPC ] ); newline();

        swrites( "gdb PSR = " ); swritex( gdb[ PSR ] ); newline();

#endif

    }

}

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

void

cyg_hal_sparc_set_gdb_regs( HAL_SavedRegisters *eCos_regset,

                            void *gdb_regset )

{

    target_register_t *gdb = (target_register_t *)gdb_regset;

    int reg;

    cyg_uint32 scratch = 0;

    cyg_uint32 *sptrap;

    HAL_SavedWindow *trapli, *ctxli;

    // Guess where the eCos register set really is:

    if ( 0 == eCos_regset->g[0]             ||

         0xc0 == (0xe0 & eCos_regset->g[0])    ) {

        // Then it's an interrupt stack saved state:

        // (either minimal, or a saved PSR with traps disabled)

        // The saved register set is pretty minimal, so we have to grub

        // around in the stack to find out some truth...

        sptrap = (cyg_uint32 *)eCos_regset; // point to the IL save area for

        sptrap -= 24;                   // the trap handler, for PC, NPC

        trapli = (HAL_SavedWindow *)sptrap; // Get at those regs

        ctxli = (HAL_SavedWindow *)(trapli->i[6]); // (the frame pointer)

                                        // and get at the interruptee's regs

        scratch = eCos_regset->g[0];

        // Put back interruptee's registers all over the stack:

        for ( reg = 0; reg < 8 ; reg++ ) {

            eCos_regset->g[reg] = gdb[ G0 + reg ] ;

            trapli->i[reg]      = gdb[ O0 + reg ] ;

            ctxli->l[reg]       = gdb[ L0 + reg ] ;

            ctxli->i[reg]       = gdb[ I0 + reg ] ;

        }

        // Put back the eCos G0 which is always 0 (but abused in eCos_regset)

        eCos_regset->g[0] = scratch;

        // In the save context _of the trap handler_ registers are as follows:

        // %l0 = psr (with this CWP/window-level in it)

        // %l1 = pc

        // %l2 = npc

        // %l3 = vector number (1-15 for interrupts)

        // %l4 = Y register preserved

        trapli->l[4] = gdb[ Y ];

        // I am *not* interfering with the saved PSR, nor the TBR nor WIM.

        // put back return PC and NPC

        trapli->l[1] = gdb[ PC ] ;

        trapli->l[2] = gdb[ NPC ];

#ifdef THREAD_DEBUG_SERIAL_VERBOSE

        newline();

        swrites( "-----------------------------------------------------" ); newline();

        swrites( "-------------- INTERRUPT STACK SET ------------------" ); newline();

        swrites( "eCos regset at " ); swritex( eCos_regset ); newline();

        swrites( "        trapli " ); swritex( trapli      ); newline();

        swrites( "         ctxli " ); swritex(  ctxli      ); newline();

        x8( "global ", &(gdb[G0]) );

        x8( "    in ", &(gdb[I0]) );

        x8( " local ", &(gdb[L0]) );

        x8( "   out ", &(gdb[O0]) );

        swrites( "gdb  PC = " ); swritex( gdb[  PC ] ); newline();

        swrites( "gdb NPC = " ); swritex( gdb[ NPC ] ); newline();

        swrites( "gdb PSR = " ); swritex( gdb[ PSR ] ); newline();

#endif

    }

    else {

        // It's a synchronous context switch that led to this object.

        // Pick up interruptee's registers from the saved context:

        scratch = eCos_regset->g[0];

        for ( reg = 0; reg < 8 ; reg++ ) {

            eCos_regset->g[reg]    = gdb[ G0 + reg ];

            eCos_regset->o[reg]    = gdb[ O0 + reg ];

            eCos_regset->li.l[reg] = gdb[ L0 + reg ];

            eCos_regset->li.i[reg] = gdb[ I0 + reg ];

        }

        // Put back the eCos G0 which is always 0 (but abused in eCos_regset)

        eCos_regset->g[0] = scratch;

        // I am *not* interfering with the saved PSR, nor the TBR nor WIM.

        // The PC is in o7, altering it via GDB's PC is not on.

        // Setting the NPC in a voluntary context is meaningless.

#ifdef THREAD_DEBUG_SERIAL_VERBOSE

        newline();

        swrites( "-----------------------------------------------------" ); newline();

        swrites( "-------------- SYNCHRONOUS SWITCH SET ---------------" ); newline();

        swrites( "eCos regset at " ); swritex( eCos_regset ); newline();

        x8( "global ", &(gdb[G0]) );

        x8( "    in ", &(gdb[I0]) );

        x8( " local ", &(gdb[L0]) );

        x8( "   out ", &(gdb[O0]) );

        swrites( "gdb  PC = " ); swritex( gdb[  PC ] ); newline();

        swrites( "gdb NPC = " ); swritex( gdb[ NPC ] ); newline();

        swrites( "gdb PSR = " ); swritex( gdb[ PSR ] ); newline();

#endif

    }

}

/*---------------------------------------------------------------------------*/

// EOF icontext.c