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/* start.S
*
* This file contains the entry veneer for RTEMS programs
* on the MBX8xx board.
* It jumps to the BSP which is responsible for performing
* all remaining initialization.
*
* This file is based on several others:
*
* (1) start360.s from the gen68360 BSP by
* W. Eric Norum (eric@skatter.usask.ca)
* with the following copyright and license:
*
* COPYRIGHT (c) 1989-1998.
* On-Line Applications Research Corporation (OAR).
* Copyright assigned to U.S. Government, 1994.
*
* The license and distribution terms for this file may in
* the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* (2) start.s for the eth_comm port by
* Jay Monkman (jmonkman@fracsa.com),
* which itself is based on the
*
* (3) dlentry.s for the Papyrus BSP, written by:
* Andrew Bray <andy@i-cubed.co.uk>
* with the following copyright and license:
*
* COPYRIGHT (c) 1995 by i-cubed ltd.
*
* (4) start860.S for the MBX821/MBX860, written by:
* Darlene A. Stewart <darlene.stewart@iit.nrc.ca>
* Copyright (c) 1999, National Research Council of Canada
*
* 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.
*
* Modifications (for MBX8xx) of respective RTEMS files:
* Copyright (c) 1999, National Research Council of Canada
*/
#include "asm.h"
/*
* The initial stack is set to run BELOW the code base address.
* (between the vectors and text sections)
*
* All the entry veneer has to do is to clear the BSS.
*/
/*
* GDB likes to have debugging information for the entry veneer.
* Play compiler and provide some DWARF information.
*
* CHANGE TO SUIT YOUR SETUP!
*/
.section .entry,"ax",@progbits
.L_text_b:
.L_LC1:
.previous
.section .debug_sfnames
.L_sfnames_b:
.byte "rtems/c/src/lib/libbsp/powerpc/mbx8xx/startup/"
.byte 0
.L_F0:
.byte "start.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 "start"
.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 "start.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 "rtems/c/src/lib/libbsp/powerpc/mbx8xx/startup/"
.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 "start"
.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
/*
* Tell C's eabi-ctor's that we have an atexit function,
* and that it is to register __do_global_dtors.
*/
EXTERN_PROC(atexit)
PUBLIC_VAR(__atexit)
.section ".sdata","aw"
.align 2
SYM(__atexit):
EXT_PROC_REF(atexit)@fixup
.previous
.section ".fixup","aw"
.align 2
EXT_SYM_REF(__atexit)
.previous
/* That should do it */
/*
* Put the entry point in its own section. That way, we can guarantee
* to put it first in the .text section in the linker script.
*/
.section .entry
PUBLIC_VAR (start)
SYM(start):
bl .startup /* or bl .spin */
base_addr:
/*
* Parameters from linker
*/
toc_pointer:
.long __GOT_START__
bss_length:
.long bss.size
bss_addr:
.long bss.start
PUBLIC_VAR (text_addr)
text_addr:
.long text.start
PUBLIC_VAR (text_length)
text_length:
.long text.size
/*
* Spin, if necessary, to acquire control from debugger (CodeWarrior).
*/
spin:
.long 0x0001
.spin:
lis r3, spin@ha
lwz r3, spin@l(r3)
cmpwi r3, 0x1
beq .spin
/*
* Initialization code
*/
.startup:
/* Get the start address. */
mflr r1
/* Initialize essential registers. */
bl initregs
nop
/*
* C_setup.
*/
/* set toc */
lwz r2, toc_pointer-base_addr(r1)
/* Set up stack pointer = beginning of text section - 56 */
addi r1, r1, -56-4
/* Initialize the memory mapped MPC821 registers (done in C). */
EXTERN_PROC (_InitMBX8xx)
bl PROC (_InitMBX8xx)
nop
/* Clear the bss section. */
bl bssclr
nop
lis 5,environ@ha
la 5,environ@l(5) /* environp */
/* clear argc and argv */
xor r3, r3, r3
xor r4, r4, r4
EXTERN_PROC (boot_card)
bl PROC (boot_card) /* call the first C routine */
nop
/* we should never return from boot_card, but in case we do ... */
/* The next instructions are dependent on your runtime environment */
/* Return to EPPCBug */
lis r10, 0x0400 /* Data cache disable */
mtspr 568, r10
isync
mtspr 560, r10 /* Instruction cache disable */
isync
stop_here:
li r10, 0x0F00 /* .RETURN */
sc
b stop_here
nop
/*
* bssclr - zero out bss
*/
bssclr:
lis r3, base_addr@ha
addi r3, r3, base_addr@l
lwz r4, bss_addr-base_addr(r3) /* Start of bss */
lwz r5, bss_length-base_addr(r3) /* Length of bss */
rlwinm. r5,r5,30,0x3FFFFFFF /* form length/4 */
beqlr /* no bss - return */
mtctr r5 /* set ctr reg */
li r5,0x0000 /* r5 = 0 */
clear_bss:
stw r5,0(r4) /* store r6 */
addi r4,r4,0x4 /* update r4 */
bdnz clear_bss /* dec counter and loop */
blr /* return */
/*
* initregs
* Initialize the MSR and basic core PowerPC registers
*
* Register usage:
* r0 - scratch
*/
initregs:
/*
* Disable address translation. We should already be running in real space,
* so this should be a no-op, i.e. no need to switch instruction stream
* addresses from virtual space to real space. Other bits set the processor
* for big-endian mode, exceptions vectored to 0x000n_nnnn (vectors are
* already in low memory!), no execution tracing, machine check exceptions
* enabled, floating-point not available (MPC8xx has none), supervisor
* priviledge level, external interrupts disabled, power management
* disabled (normal operation mode).
*/
li r0, 0x1000 /* MSR_ME */
mtmsr r0 /* Context-synchronizing */
isync
/*
* Clear the exception handling registers.
* Note SPRG3 is reserved for use by EPPCBug on the MBX8xx.
*/
li r0, 0x0000
mtdar r0
mtspr sprg0, r0
mtspr sprg1, r0
mtspr sprg2, r0
mtspr srr0, r0
mtspr srr1, r0
mr r6, r0
mr r7, r0
mr r8, r0
mr r9, r0
mr r10, r0
mr r11, r0
mr r12, r0
mr r13, r0
mr r14, r0
mr r15, r0
mr r16, r0
mr r17, r0
mr r18, r0
mr r19, r0
mr r20, r0
mr r21, r0
mr r22, r0
mr r23, r0
mr r24, r0
mr r25, r0
mr r26, r0
mr r27, r0
mr r28, r0
mr r29, r0
mr r30, r0
mr r31, r0
blr /* return */
.L_text_e:
.comm environ,4,4
|
