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|
/* Sample initialization file */
.extern main
.extern exit
.extern AT91F_LowLevelInit
.text
.code 32
.align 0
.extern __stack_end__
.extern __bss_beg__
.extern __bss_end__
.extern __data_beg__
.extern __data_end__
.extern __data+beg_src__
.global start
.global endless_loop
/* Stack Sizes */
.set UND_STACK_SIZE, 0x00000004
.set ABT_STACK_SIZE, 0x00000004
.set FIQ_STACK_SIZE, 0x00000400
.set IRQ_STACK_SIZE, 0X00000400
.set SVC_STACK_SIZE, 0x00000400
/* Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs */
.set MODE_USR, 0x10 /* User Mode */
.set MODE_FIQ, 0x11 /* FIQ Mode */
.set MODE_IRQ, 0x12 /* IRQ Mode */
.set MODE_SVC, 0x13 /* Supervisor Mode */
.set MODE_ABT, 0x17 /* Abort Mode */
.set MODE_UND, 0x1B /* Undefined Mode */
.set MODE_SYS, 0x1F /* System Mode */
.equ I_BIT, 0x80 /* when I bit is set, IRQ is disabled */
.equ F_BIT, 0x40 /* when F bit is set, FIQ is disabled */
.equ AT91C_BASE_AIC, (0xFFFFF000)
.equ AT91C_BASE_PIOA, 0xFFFFF400
.equ AT91C_BASE_TC0, 0xFFFA0000
.equ AT91C_TC_SWTRG, (1 << 2)
.equ PIO_DATA, (1 << 27)
.equ PIOA_SODR, 0x30
.equ PIOA_CODR, 0x34
.equ PIOA_PDSR, 0x3c
.equ PIOA_IDR, 0x44
.equ PIOA_ISR, 0x4c
.equ TC_CCR, 0x00
.equ AIC_EOICR, (304)
/*.equ PIO_LED1, (1 << 25)*/
.equ PIO_LED1, (1 << 12)
start:
_start:
_mainCRTStartup:
/* Setup a stack for each mode - note that this only sets up a usable stack
for system/user, SWI and IRQ modes. Also each mode is setup with
interrupts initially disabled. */
ldr r0, .LC6
msr CPSR_c, #MODE_UND|I_BIT|F_BIT /* Undefined Instruction Mode */
mov sp, r0
sub r0, r0, #UND_STACK_SIZE
msr CPSR_c, #MODE_ABT|I_BIT|F_BIT /* Abort Mode */
mov sp, r0
sub r0, r0, #ABT_STACK_SIZE
msr CPSR_c, #MODE_FIQ|I_BIT|F_BIT /* FIQ Mode */
/* Preload registers for FIQ handler */
ldr r10, =AT91C_BASE_PIOA
ldr r12, =AT91C_BASE_TC0
ldr r8, =AT91C_BASE_AIC
mov r9, #AT91C_TC_SWTRG
mov sp, r0
sub r0, r0, #FIQ_STACK_SIZE
msr CPSR_c, #MODE_IRQ|I_BIT|F_BIT /* IRQ Mode */
mov sp, r0
sub r0, r0, #IRQ_STACK_SIZE
msr CPSR_c, #MODE_SVC|I_BIT|F_BIT /* Supervisor Mode */
mov sp, r0
sub r0, r0, #SVC_STACK_SIZE
msr CPSR_c, #MODE_SYS|I_BIT|F_BIT /* System Mode */
mov sp, r0
/* We want to start in supervisor mode. Operation will switch to system
mode when the first task starts. */
msr CPSR_c, #MODE_SVC|I_BIT|F_BIT
bl AT91F_LowLevelInit
/* Clear BSS. */
mov a2, #0 /* Fill value */
mov fp, a2 /* Null frame pointer */
mov r7, a2 /* Null frame pointer for Thumb */
ldr r1, .LC1 /* Start of memory block */
ldr r3, .LC2 /* End of memory block */
subs r3, r3, r1 /* Length of block */
beq .end_clear_loop
mov r2, #0
.clear_loop:
strb r2, [r1], #1
subs r3, r3, #1
bgt .clear_loop
.end_clear_loop:
/* Initialise data. */
ldr r1, .LC3 /* Start of memory block */
ldr r2, .LC4 /* End of memory block */
ldr r3, .LC5
subs r3, r3, r1 /* Length of block */
beq .end_set_loop
.set_loop:
ldrb r4, [r2], #1
strb r4, [r1], #1
subs r3, r3, #1
bgt .set_loop
.end_set_loop:
mov r0, #0 /* no arguments */
mov r1, #0 /* no argv either */
ldr lr, =main
bx lr
endless_loop:
b endless_loop
.align 0
.LC1:
.word __bss_beg__
.LC2:
.word __bss_end__
.LC3:
.word __data_beg__
.LC4:
.word __data_beg_src__
.LC5:
.word __data_end__
.LC6:
.word __stack_end__
/* Setup vector table. Note that undf, pabt, dabt, fiq just execute
a null loop. */
.section .startup,"ax"
.code 32
.align 0
b _start /* reset - _start */
ldr pc, _undf /* undefined - _undf */
ldr pc, _swi /* SWI - _swi */
ldr pc, _pabt /* program abort - _pabt */
ldr pc, _dabt /* data abort - _dabt */
nop /* reserved */
ldr pc, [pc,#-0xF20] /* IRQ - read the AIC */
ldr pc, [pc,#-0xF20] /* FIQ - read the AIC */
_undf: .word __undf /* undefined */
_swi: .word swi_handler /* SWI */
_pabt: .word __pabt /* program abort */
_dabt: .word __dabt /* data abort */
_fiq: .word __fiq /* FIQ */
__undf: b . /* undefined */
__pabt: b . /* program abort */
__dabt: b . /* data abort */
__fiq: b . /* FIQ */
/* Following is from openpcd/firmware/src/start/Cstartup_app.S */
#define LED_TRIGGER
/*#define CALL_PIO_IRQ_DEMUX*/
.text
.arm
.section .fastrun, "ax"
.global fiq_handler
.func fiq_handler
fiq_handler:
/* code that uses pre-initialized FIQ reg */
/* r8 AT91C_BASE_AIC (dfu init)
r9 AT91C_TC_SWTRG
r10 AT91C_BASE_PIOA
r11 tmp
r12 AT91C_BASE_TC0
r13 stack
r14 lr
*/
ldr r8, [r10, #PIOA_ISR]
tst r8, #PIO_DATA /* check for PIO_DATA change */
ldrne r11, [r10, #PIOA_PDSR]
tstne r11, #PIO_DATA /* check for PIO_DATA == 1 */
strne r9, [r12, #TC_CCR] /* software trigger */
#ifdef LED_TRIGGER
movne r11, #PIO_LED1
strne r11, [r10, #PIOA_CODR] /* enable LED */
#endif
#if 1
movne r11, #PIO_DATA
strne r11, [r10, #PIOA_IDR] /* disable further PIO_DATA FIQ */
#endif
/*- Mark the End of Interrupt on the AIC */
ldr r11, =AT91C_BASE_AIC
str r11, [r11, #AIC_EOICR]
#ifdef LED_TRIGGER
mov r11, #PIO_LED1
str r11, [r10, #PIOA_SODR] /* disable LED */
#endif
#ifdef CALL_PIO_IRQ_DEMUX
/* push r0, r1-r3, r12, r14 onto FIQ stack */
/*stmfd sp!, { r0-r3, r12, lr}
mov r0, r8*/
/* enable interrupts while handling demux */
/* enable interrupts while handling demux */
/* msr CPSR_c, #F_BIT | ARM_MODE_SVC */
/* Call C function, give PIOA_ISR as argument */
/*ldr r11, =__pio_irq_demux
mov r14, pc
bx r11*/
/* msr CPSR_c, #I_BIT | F_BIT | ARM_MODE_FIQ */
/*ldmia sp!, { r0-r3, r12, lr }*/
#endif
/*- Restore the Program Counter using the LR_fiq directly in the PC */
subs pc, lr, #4
.size fiq_handler, . - fiq_handler
.endfunc
.end
|
