📄 start_up.s
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/* *******************************************************
* NAME : 44BINIT.S *
* Version : 10.JAn.2003 *
* Description: *
* C start up codes *
* Configure memory, Initialize ISR ,stacks *
* Initialize C-variables *
* Fill zeros into zero-initialized C-variables *
*******************************************************/
//#include "arm.h"
.globl _start
_start:
b ResetHandler //for debug
b HandlerUndef //handlerUndef
b HandlerSWI //SWI interrupt handler
b HandlerPabort //handlerPAbort
b HandlerDabort //handlerDAbort
b . //handlerReserved
b IsrIRQ
b HandlerFIQ
//***IMPORTANT NOTE***
//If the H/W vectored interrutp mode is enabled, The above two instructions should
//be changed like below, to work-around with H/W bug of S3C44B0X interrupt controller.
ldr pc,=HandlerEINT0 //mGA H/W interrupt vector table
ldr pc,=HandlerEINT1 //
ldr pc,=HandlerEINT2 //
ldr pc,=HandlerEINT3 //
ldr pc,=HandlerEINT4567 //
ldr pc,=HandlerTICK //mGA
b .
b .
ldr pc,=HandlerZDMA0 //mGB
ldr pc,=HandlerZDMA1 //
ldr pc,=HandlerBDMA0 //
ldr pc,=HandlerBDMA1 //
ldr pc,=HandlerWDT //
ldr pc,=HandlerUERR01 //mGB
b .
b .
ldr pc,=HandlerTIMER0 //mGC
ldr pc,=HandlerTIMER1 //
ldr pc,=HandlerTIMER2 //
ldr pc,=HandlerTIMER3 //
ldr pc,=HandlerTIMER4 //
ldr pc,=HandlerTIMER5 //mGC
b .
b .
ldr pc,=HandlerURXD0 //mGD
ldr pc,=HandlerURXD1 //
ldr pc,=HandlerIIC //
ldr pc,=HandlerSIO //
ldr pc,=HandlerUTXD0 //
ldr pc,=HandlerUTXD1 //mGD
b .
b .
ldr pc,=HandlerRTC //mGKA
b . //
b . //
b . //
b . //
b . //mGKA
b .
b .
ldr pc,=HandlerADC //mGKB
b . //
b . //
b . //
b . //
b . //mGKB
b .
b .
/*0xe0=EnterPWDN*/
ldr pc,=EnterPWDN
HandlerFIQ: .word HandleFIQ
HandlerIRQ: .word HandleIRQ
HandlerUndef: .word HandleUndef
HandlerSWI: .word HandleSWI
HandlerDabort: .word HandleDabort
HandlerPabort: .word HandlePabort
HandlerADC: .word HandleADC
HandlerRTC: .word HandleRTC
HandlerUTXD1: .word HandleUTXD1
HandlerUTXD0: .word HandleUTXD0
HandlerSIO: .word HandleSIO
HandlerIIC: .word HandleIIC
HandlerURXD1: .word HandleURXD1
HandlerURXD0: .word HandleURXD0
HandlerTIMER5: .word HandleTIMER5
HandlerTIMER4: .word HandleTIMER4
HandlerTIMER3: .word HandleTIMER3
HandlerTIMER2: .word HandleTIMER2
HandlerTIMER1: .word HandleTIMER1
HandlerTIMER0: .word HandleTIMER0
HandlerUERR01: .word HandleUERR01
HandlerWDT: .word HandleWDT
HandlerBDMA1: .word HandleBDMA1
HandlerBDMA0: .word HandleBDMA0
HandlerZDMA1: .word HandleZDMA1
HandlerZDMA0: .word HandleZDMA0
HandlerTICK: .word HandleTICK
HandlerEINT4567: .word HandleEINT4567
HandlerEINT3: .word HandleEINT3
HandlerEINT2: .word HandleEINT2
HandlerEINT1: .word HandleEINT1
HandlerEINT0: .word HandleEINT0
/*One of the following two routines can be used for non-vectored interrupt.*/
IsrIRQ: //using I_ISPR register.
stmdb r13!,{r0-r8,r12,r14}
bl IRQ
ldmia r13!,{r0-r8,r12,r14}
subs pc,r14,#0x4
IRQ:
sub sp,sp,#4 //reserved for PC
stmfd sp!,{r8-r9}
ldr r9,I_ISPR
ldr r9,[r9]
mov r8,#0x0
F0:
movs r9,r9,lsr #1
bcs F1
add r8,r8,#4
b F0
F1:
ldr r9,HandleADC
add r9,r9,r8
ldr r9,[r9]
str r9,[sp,#8]
ldmfd sp!,{r8-r9,pc}
/*****************************************************
* START *
*****************************************************/
ResetHandler:
ldr r0,WTCON //watch dog disable
ldr r1,=0x0
str r1,[r0]
ldr r0,INTMSK
ldr r1,MASKALL //all interrupt disable
str r1,[r0]
/* ****************************************************
* Set clock control registers *
*****************************************************/
ldr r0,LOCKTIME
ldr r1,=800 // count = t_lock * Fin (t_lock=200us, Fin=4MHz) = 800
str r1,[r0]
ldr r0,PLLCON //temporary setting of PLL
ldr r1,PLLCON_DAT //Fin=10MHz,Fout=40MHz
str r1,[r0]
ldr r0,CLKCON
ldr r1,=0x7ff8 //All unit block CLK enable
str r1,[r0]
/* ****************************************************
* Set memory control registers *
*****************************************************/
adr r0,SMRDATA
ldmia r0,{r1-r13}
ldr r0,=0x01c80000 //BWSCON Address
stmia r0,{r1-r13}
/* ***************************************************
* Initialize stacks *
*****************************************************/
ldr sp, SVCStack //Why?
bl InitStacks
/* ****************************************************
* Setup IRQ handler *
*****************************************************/
ldr r0,HandleIRQ //This routine is needed
ldr r1,IsrIRQ //if there isn't 'subs pc,lr,#4' at 0x18, 0x1c
str r1,[r0]
BL Main //Don't use main() because ......
B .
/*****************************************************
The function for initializing stack *
/*****************************************************/
InitStacks:
//Don't use DRAM,such as stmfd,ldmfd......
//SVCstack is initialized before
//Under toolkit ver 2.50, 'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1'
mrs r0,cpsr
bic r0,r0,#0X1F
orr r1,r0,#0xDB //UNDEFMODE|NOINT
msr cpsr,r1 //UndefMode
ldr sp,UndefStack
orr r1,r0,#0XD7 //ABORTMODE|NOINT
msr cpsr,r1 //AbortMode
ldr sp,AbortStack
orr r1,r0,#0XD2 //IRQMODE|NOINT
msr cpsr,r1 //IRQMode
ldr sp,IRQStack
orr r1,r0,#0XD1 //FIQMODE|NOINT
msr cpsr,r1 //FIQMode
ldr sp,FIQStack
bic r0,r0,#0XDF //MODEMASK|NOINT
orr r1,r0,#0X13
msr cpsr,r1 //SVCMode
ldr sp,SVCStack
//USER mode is not initialized.
mov pc,lr //The LR register may be not valid for the mode changes.
/*****************************************************
* The function for entering power down mode *
*****************************************************/
/*void EnterPWDN(int CLKCON)*/
EnterPWDN:
mov r2,r0 //r0=CLKCON
ldr r0,REFRESH
ldr r3,[r0]
mov r1, r3
orr r1, r1, #0x400000 //self-refresh enable
str r1, [r0]
nop //Wait until self-refresh is issued. May not be needed.
nop //If the other bus master holds the bus, ...
nop // mov r0, r0
nop
nop
nop
nop
/*enter POWERDN mode*/
ldr r0,CLKCON
str r2,[r0]
/*wait until enter SL_IDLE,STOP mode and until wake-up*/
mov r0,#0xff
B0: subs r0,r0,#1
bne B0
/*exit from DRAM/SDRAM self refresh mode.*/
ldr r0,REFRESH
str r3,[r0]
mov pc,lr
SMRDATA:
/******************************************************************
* Memory configuration has to be optimized for best performance *
* The following parameter is not optimized. *
******************************************************************/
/**** memory access cycle parameter strategy ***
// 1) Even FP-DRAM, EDO setting has more late fetch point by half-clock
// 2) The memory settings,here, are made the safe parameters even at 66Mhz.
// 3) FP-DRAM Parameters:tRCD=3 for tRAC, tcas=2 for pad delay, tcp=2 for bus load.
// 4) DRAM refresh rate is for 40Mhz. */
.long 0x11110090 //Bank0=OM[1:0], Bank1~Bank7=16bit, bank2=8bit//
.long 0X600 //GCS0
.long 0X7bc0 //GCS1
.long 0X7fc0 //GCS2
.long 0X7ffc //GCS3
.long 0X7ffc //GCS4
.long 0X7ffc //GCS5
.long 0X18000 //GCS6
.long 0X18000 //GCS7
.long 0x820591 //REFRESH RFEN=1, TREFMD=0, trp=3clk, trc=5clk, tchr=3clk,count=1019
.long 0x16 //SCLK power mode, BANKSIZE 32M/32M
.long 0x20 //MRSR6 CL=2clk
.long 0x20 //MRSR7
UserStack: .word 0xc7ffa00
SVCStack: .word 0xc7ffb00
UndefStack: .word 0xc7ffc00
AbortStack: .word 0xc7ffd00
IRQStack: .word 0xc7ffe00
FIQStack: .word 0xc7fff00
HandleReset: .word 0xc7fff00
HandleUndef: .word 0xc7fff04
HandleSWI: .word 0xc7fff08
HandlePabort: .word 0xc7fff0c
HandleDabort: .word 0xc7fff10
HandleReserved: .word 0xc7fff14
HandleIRQ: .word 0xc7fff18
HandleFIQ: .word 0xc7fff1c
//Don't use the label 'IntVectorTable',
//because armasm.exe cann't recognize this label correctly.
//the value is different with an address you think it may be.
//IntVectorTable
HandleADC: .word 0xc7fff20
HandleRTC: .word 0xc7fff24
HandleUTXD1: .word 0xc7fff28
HandleUTXD0: .word 0xc7fff2c
HandleSIO: .word 0xc7fff30
HandleIIC: .word 0xc7fff34
HandleURXD1: .word 0xc7fff38
HandleURXD0: .word 0xc7fff3c
HandleTIMER5: .word 0xc7fff40
HandleTIMER4: .word 0xc7fff44
HandleTIMER3: .word 0xc7fff48
HandleTIMER2: .word 0xc7fff4c
HandleTIMER1: .word 0xc7fff50
HandleTIMER0: .word 0xc7fff54
HandleUERR01: .word 0xc7fff58
HandleWDT: .word 0xc7fff5c
HandleBDMA1: .word 0xc7fff60
HandleBDMA0: .word 0xc7fff64
HandleZDMA1: .word 0xc7fff68
HandleZDMA0: .word 0xc7fff6c
HandleTICK: .word 0xc7fff70
HandleEINT4567: .word 0xc7fff74
HandleEINT3: .word 0xc7fff78
HandleEINT2: .word 0xc7fff7c
HandleEINT1: .word 0xc7fff80
HandleEINT0: .word 0xc7fff84
/* some parameters for the board */
/*Interrupt Control*/
INTPND:
.long 0x01e00004
INTMOD:
.long 0x01e00008
INTMSK:
.long 0x01e0000c
I_ISPR:
.long 0x01e00020
I_CMST:
.long 0x01e0001c
/*;Watchdog timer*/
WTCON:
.long 0x01d30000
/*;Clock Controller*/
PLLCON:
.long 0x01d80000
CLKCON:
.long 0x01d80004
LOCKTIME:
.long 0x01d8000c
/*;Memory Controller*/
REFRESH:
.long 0x01c80024
/*;Pre-defined constants*/
USERMODE:
.long 0x10
FIQMODE:
.long 0x11
IRQMODE:
.long 0x12
SVCMODE:
.long 0x13
ABORTMODE:
.long 0x17
UNDEFMODE:
.long 0x1b
MODEMASK:
.long 0x1f
NOINT:
.long 0xc0
_ISR_STARTADDRESS:
.long 0xc7fff00 //GCS6:64M DRAM/SDRAM
PLLCLK:
.long 40000000
PLLCON_DAT:
.long ((2 << 0) + (3 << 4) +( 0x48<< 12))
MASKALL:
.long 0x07ffffff
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