/*
* start.S : RTEMS entry point
*
* Copyright (C) 2000 Canon Research Centre France SA.
* Emmanuel Raguet, mailto:raguet@crf.canon.fr
*
* The license and distribution terms for this file may be
* found in found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
*/
.equ ABORT_Stack, 0
.equ IRQ_Stack, 0x100
.equ FIQ_Stack, 0x200
.equ SVC_Stack, 0x300
/* Some standard definitions...*/
.equ Mode_USR, 0x10
.equ Mode_FIQ, 0x11
.equ Mode_IRQ, 0x12
.equ Mode_SVC, 0x13
.equ Mode_ABT, 0x17
.equ Mode_ABORT, 0x17
.equ Mode_UNDEF, 0x1B
.equ Mode_SYS, 0x1F /*only available on ARM Arch. v4*/
.equ I_Bit, 0x80
.equ F_Bit, 0x40
.text
.globl _start
_start:
/*
* Here is the code to initialize the low-level BSP environment
* (Chip Select, PLL, ....?)
/* Copy data from FLASH to RAM */
LDR r0, =_initdata /* load address of region */
LDR r1, =0x400000 /* execution address of region */
LDR r2, =_edata /* copy execution address into r2 */
copy:
CMP r1, r2 /* loop whilst r1 < r2 */
LDRLO r3, [r0], #4
STRLO r3, [r1], #4
BLO copy
/* zero the bss */
LDR r1, =__bss_end__ /* get end of ZI region */
LDR r0, =__bss_start__ /* load base address of ZI region */
zi_init:
MOV r2, #0
CMP r0, r1 /* loop whilst r0 < r1 */
STRLOT r2, [r0], #4
BLO zi_init
/* Load basic ARM7 interrupt table */
VectorInit:
MOV R8, #0
ADR R9, Vector_Init_Block
LDMIA R9!, {R0-R7} /* Copy the Vectors (8 words) */
STMIA R8!, {R0-R7}
LDMIA R9!, {R0-R7} /* Copy the .long'ed addresses (8 words) */
STMIA R8!, {R0-R7}
B init2
/*******************************************************
standard exception vectors table
*** Must be located at address 0
********************************************************/
Vector_Init_Block:
LDR PC, Reset_Addr
LDR PC, Undefined_Addr
LDR PC, SWI_Addr
LDR PC, Prefetch_Addr
LDR PC, Abort_Addr
NOP
LDR PC, IRQ_Addr
LDR PC, FIQ_Addr
.globl Reset_Addr
Reset_Addr: .long _start
Undefined_Addr: .long Undefined_Handler
SWI_Addr: .long SWI_Handler
Prefetch_Addr: .long Prefetch_Handler
Abort_Addr: .long Abort_Handler
.long 0
IRQ_Addr: .long IRQ_Handler
FIQ_Addr: .long FIQ_Handler
/* The following handlers do not do anything useful */
.globl Undefined_Handler
Undefined_Handler:
B Undefined_Handler
.globl SWI_Handler
SWI_Handler:
B SWI_Handler
.globl Prefetch_Handler
Prefetch_Handler:
B Prefetch_Handler
.globl Abort_Handler
Abort_Handler:
B Abort_Handler
.globl IRQ_Handler
IRQ_Handler:
B IRQ_Handler
.globl FIQ_Handler
FIQ_Handler:
B FIQ_Handler
init2 :
/* --- Initialise stack pointer registers
Set up the ABORT stack pointer last and stay in SVC mode */
MOV r0, #(Mode_ABORT | I_Bit | F_Bit) /* No interrupts */
MSR cpsr, r0
LDR sp, =ABORT_Stack
/* Enter IRQ mode and set up the IRQ stack pointer */
MOV r0, #Mode_IRQ | I_Bit | F_Bit /* No interrupts */
MSR cpsr, r0
LDR sp, =IRQ_Stack
/* Enter FIQ mode and set up the FIQ stack pointer */
MOV r0, #Mode_FIQ | I_Bit | F_Bit /* No interrupts */
MSR cpsr, r0
LDR sp, =FIQ_Stack
/* Set up the SVC stack pointer last and stay in SVC mode */
MOV r0, #Mode_SVC | I_Bit | F_Bit /* No interrupts */
MSR cpsr, r0
LDR sp, =SVC_Stack
/* --- Now we enter the C code */
B boot_card
