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/*  dlentry.s   1.0 - 95/08/08

 *

 *  This file contains the entry veneer for RTEMS programs

 *  downloaded to Papyrus.

 *

 *  Author:     Andrew Bray 

 *

 *  COPYRIGHT (c) 1995 by i-cubed ltd.

 *

 *  To anyone who acknowledges that this file is provided "AS IS"

 *  without any express or implied warranty:

 *      permission to use, copy, modify, and distribute this file

 *      for any purpose is hereby granted without fee, provided that

 *      the above copyright notice and this notice appears in all

 *      copies, and that the name of i-cubed limited not be used in

 *      advertising or publicity pertaining to distribution of the

 *      software without specific, written prior permission.

 *      i-cubed limited makes no representations about the suitability

 *      of this software for any purpose.

 *

 *  $Id: dlentry.S,v 1.2 2001-09-27 12:00:41 chris Exp $

 */

#include "asm.h"

/*

 *  The Papyrus ELF link scripts support three special sections:

 *    .entry    The actual entry point, this must contain less

 *              than 256 bytes of code/data to fit below the

 *              .vectors section.  This always preceeds any other

 *              code or data.

 *    .vectors  The section containing the interrupt entry veneers.

 *    .entry2   Any code overflowing from .entry

 *    .descriptors The PowerOpen function indirection blocks.

 */

/*

 *  Downloaded code loads the vectors separately to 0x00000100,

 *  so .entry can be over 256 bytes.

 *

 *  The other sections are linked in the following order:

 *    .entry

 *    .entry2

 *    .text

 *    .descriptors

 *    .data

 *    .bss

 *  usually starting from 0x00020000.

 *

 *  The initial stack is set to run BELOW the code base address.

 *

 *  All the entry veneer has to do is to clear the BSS.

 */

/*

 *  GDB likes to have debugging information for the entry veneer.

 *  Here is some DWARF information.

 */

#if PPC_ASM == PPC_ASM_ELF

        .section .entry,"ax",@progbits

.L_text_b:

.L_LC1:

        .previous

.section        .debug_sfnames

.L_sfnames_b:

        .byte "/home/andy/powerpc/rtems-3.2.0/c/src/lib/libcpu/ppc/ppc403/dlentry/"

        .byte 0

.L_F0:

        .byte "dlentry.s"

        .byte 0

        .previous

.section        .line

.L_line_b:

        .4byte  .L_line_e-.L_line_b

        .4byte  .L_text_b

.L_LE1:

.L_line_last:

        .4byte  0x0

        .2byte  0xffff

        .4byte  .L_text_e-.L_text_b

.L_line_e:

        .previous

.section        .debug_srcinfo

.L_srcinfo_b:

        .4byte  .L_line_b

        .4byte  .L_sfnames_b

        .4byte  .L_text_b

        .4byte  .L_text_e

        .4byte  0xffffffff

        .4byte  .L_LE1-.L_line_b

        .4byte  .L_F0-.L_sfnames_b

        .4byte  .L_line_last-.L_line_b

        .4byte  0xffffffff

        .previous

.section        .debug_pubnames

        .4byte  .L_debug_b

        .4byte  .L_P0

        .byte "download_entry"

        .byte 0

        .4byte  0x0

        .byte 0

        .previous

.section        .debug_aranges

        .4byte  .L_debug_b

        .4byte  .L_text_b

        .4byte  .L_text_e-.L_text_b

        .4byte  0

        .4byte  0

        .4byte  0

        .4byte  0

        .4byte  0

        .4byte  0

        .4byte  0x0

        .4byte  0x0

        .previous

.section        .debug

.L_debug_b:

.L_D1:

        .4byte  .L_D1_e-.L_D1

        .2byte  0x11    /* TAG_compile_unit */

        .2byte  0x12    /* AT_sibling */

        .4byte  .L_D2

        .2byte  0x38    /* AT_name */

        .byte "dlentry.s"

        .byte 0

        .2byte  0x258   /* AT_producer */

        .byte "GAS 2.5.2"

        .byte 0

        .2byte  0x111   /* AT_low_pc */

        .4byte  .L_text_b

        .2byte  0x121   /* AT_high_pc */

        .4byte  .L_text_e

        .2byte  0x106   /* AT_stmt_list */

        .4byte  .L_line_b

        .2byte  0x1b8   /* AT_comp_dir */

        .byte "/home/andy/powerpc/rtems-3.2.0/c/src/lib/libcpu/ppc/ppc403/dlentry/"

        .byte 0

        .2byte  0x8006  /* AT_sf_names */

        .4byte  .L_sfnames_b

        .2byte  0x8016  /* AT_src_info */

        .4byte  .L_srcinfo_b

.L_D1_e:

.L_P0:

.L_D3:

        .4byte  .L_D3_e-.L_D3

        .2byte  0x6     /* TAG_global_subroutine */

        .2byte  0x12    /* AT_sibling */

        .4byte  .L_D4

        .2byte  0x38    /* AT_name */

        .byte "download_entry"

        .byte 0

        .2byte  0x278   /* AT_prototyped */

        .byte 0

        .2byte  0x111   /* AT_low_pc */

        .4byte  .L_text_b

        .2byte  0x121   /* AT_high_pc */

        .4byte  .L_text_e

        .2byte  0x8041  /* AT_body_begin */

        .4byte  .L_text_b

        .2byte  0x8051  /* AT_body_end */

        .4byte  .L_text_e

.L_D3_e:

.L_D4:

        .4byte  .L_D4_e-.L_D4

        .align 2

.L_D4_e:

.L_D2:

        .previous

#endif

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

 * ROM Vector area.

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

#if PPC_ASM == PPC_ASM_ELF

        .section .entry

#else

        .csect .text[PR]

#endif

        PUBLIC_VAR (download_entry)

SYM(download_entry):

        bl      .startup

base_addr:

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

 * Parameters from linker

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

toc_pointer:

#if PPC_ASM == PPC_ASM_ELF

        .long   s.got

#else

        .long   TOC[tc0]

#endif

bss_length:

        .long   bss.size

bss_addr:

        .long   bss.start

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

 * Reset_entry.

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

.startup:

        /* Get start address, stack grows down from here... */

        mflr    r1

        /* Assume Bank regs set up..., cache etc. */

        bl      bssclr

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

         * C_setup.

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

        lwz     r2,toc_pointer-base_addr(r1)       /* set r2 to toc */

        addi    r1,r1,-56-4              /* start stack at text_addr - 56 */

        addi    r3,r0,0x0                /* clear r3 */

        stw     r3, 0(r1)                /* Clear stack chain */

        stw     r3, 4(r1)

        stw     r3, 8(r1)

        stw     r3, 12(r1)

        .extern SYM (boot_card)

        b       SYM (boot_card)          /* call the first C routine */

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

 * bssclr.

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

bssclr:

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

         * Data move finished, zero out bss.

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

        lwz     r2,bss_addr-base_addr(r1)         /* start of bss set by loader */

        lwz     r3,bss_length-base_addr(r1)       /* bss length */

        rlwinm. r3,r3,30,0x3FFFFFFF     /* form length/4 */

        beqlr                           /* no bss */

        mtctr   r3                      /* set ctr reg */

        xor     r6,r6,r6                /* r6 = 0 */

clear_bss:

        stswi   r6,r2,0x4               /* store r6 */

        addi    r2,r2,0x4               /* update r2 */

        bdnz    clear_bss               /* decrement counter and loop */

        blr                             /* return */

.L_text_e:

#if PPC_ABI == PPC_ABI_POWEROPEN

        DESCRIPTOR (startup)

#endif