152 lines
3.4 KiB
ArmAsm
152 lines
3.4 KiB
ArmAsm
/*
|
|
* File : start_gcc.S
|
|
* Change Logs:
|
|
* Date Author Notes
|
|
* 2010-05-17 swkyer first version
|
|
* 2010-09-04 bernard porting to Jz47xx
|
|
*/
|
|
|
|
#include "../common/mips.inc"
|
|
#include "../common/stackframe.h"
|
|
#include "jz47xx.h"
|
|
|
|
.section ".start", "ax"
|
|
.set noreorder
|
|
|
|
/* the program entry */
|
|
.globl _start
|
|
_start:
|
|
.set noreorder
|
|
la ra, _start
|
|
|
|
/* init cp0 registers. */
|
|
li t0, 0x0000FC00 /* BEV = 0 and mask all interrupt */
|
|
mtc0 t0, CP0_STATUS
|
|
|
|
li t1, 0x00800000
|
|
mtc0 t1, CP0_CAUSE
|
|
|
|
/* setup stack pointer */
|
|
li sp, SYSTEM_STACK
|
|
la gp, _gp
|
|
|
|
/* init caches, assumes a 4way * 128set * 32byte I/D cache */
|
|
li t0, 3 /* enable cache for kseg0 accesses */
|
|
mtc0 t0, CP0_CONFIG /* CONFIG reg */
|
|
la t0, 0x80000000 /* an idx op should use an unmappable address */
|
|
ori t1, t0, 0x4000 /* 16kB cache */
|
|
mtc0 zero, CP0_TAGLO /* TAGLO reg */
|
|
mtc0 zero, CP0_TAGHI /* TAGHI reg */
|
|
|
|
_cache_loop:
|
|
cache 0x8, 0(t0) /* index store icache tag */
|
|
cache 0x9, 0(t0) /* index store dcache tag */
|
|
bne t0, t1, _cache_loop
|
|
addiu t0, t0, 0x20 /* 32 bytes per cache line */
|
|
nop
|
|
|
|
/* invalidate BTB */
|
|
mfc0 t0, CP0_CONFIG
|
|
nop
|
|
ori t0, 2
|
|
mtc0 t0, CP0_CONFIG
|
|
nop
|
|
|
|
/* copy IRAM section */
|
|
la t0, _iramcopy
|
|
la t1, _iramstart
|
|
la t2, _iramend
|
|
_iram_loop:
|
|
lw t3, 0(t0)
|
|
sw t3, 0(t1)
|
|
addiu t1, 4
|
|
bne t1, t2, _iram_loop
|
|
addiu t0, 4
|
|
|
|
/* clear bss */
|
|
la t0, __bss_start
|
|
la t1, __bss_end
|
|
_clr_bss_loop:
|
|
sw zero, 0(t0)
|
|
bne t0, t1, _clr_bss_loop
|
|
addiu t0, t0, 4
|
|
|
|
/* jump to RT-Thread RTOS */
|
|
jal rtthread_startup
|
|
nop
|
|
|
|
/* restart, never die */
|
|
j _start
|
|
nop
|
|
.set reorder
|
|
|
|
.globl cp0_get_cause
|
|
cp0_get_cause:
|
|
mfc0 v0, CP0_CAUSE
|
|
jr ra
|
|
nop
|
|
|
|
.globl cp0_get_status
|
|
cp0_get_status:
|
|
mfc0 v0, CP0_STATUS
|
|
jr ra
|
|
nop
|
|
|
|
.globl cp0_get_hi
|
|
cp0_get_hi:
|
|
mfhi v0
|
|
jr ra
|
|
nop
|
|
|
|
.globl cp0_get_lo
|
|
cp0_get_lo:
|
|
mflo v0
|
|
jr ra
|
|
nop
|
|
|
|
.extern tlb_refill_handler
|
|
.extern cache_error_handler
|
|
|
|
/* Exception Handler */
|
|
/* 0x0 - TLB refill handler */
|
|
.section .vectors.1, "ax", %progbits
|
|
j tlb_refill_handler
|
|
nop
|
|
|
|
/* 0x100 - Cache error handler */
|
|
.section .vectors.2, "ax", %progbits
|
|
j cache_error_handler
|
|
nop
|
|
|
|
/* 0x180 - Exception/Interrupt handler */
|
|
.section .vectors.3, "ax", %progbits
|
|
j _general_exception_handler
|
|
nop
|
|
|
|
/* 0x200 - Special Exception Interrupt handler (when IV is set in CP0_CAUSE) */
|
|
.section .vectors.4, "ax", %progbits
|
|
j _irq_handler
|
|
nop
|
|
|
|
.section .vectors, "ax", %progbits
|
|
.extern mips_irq_handle
|
|
|
|
/* general exception handler */
|
|
_general_exception_handler:
|
|
.set noreorder
|
|
mfc0 k1, CP0_CAUSE
|
|
andi k1, k1, 0x7c
|
|
srl k1, k1, 2
|
|
lw k0, sys_exception_handlers(k1)
|
|
jr k0
|
|
nop
|
|
.set reorder
|
|
|
|
/* interrupt handler */
|
|
_irq_handler:
|
|
.set noreorder
|
|
la k0, mips_irq_handle
|
|
jr k0
|
|
nop
|
|
.set reorder
|