Sorry, I am newbie, I am just starting to explore assembly with ARM. I am trying to run example from the book
AREA Prog1, CODE, READONLY
ENTRY
MOV r0, #0x11 ; load initial value
LSL r1, r0, #1 ; shift 1 bit left
LSL r2, r1, #1 ; shift 1 bit left
stop B stop ; stop program
END
But as far as I know program should have RESET area vector set in order to start execution.
So I added Startup.s file into my project
;/*****************************************************************************/
;/* STARTUP.S: Startup file for Philips LPC2000 */
;/*****************************************************************************/
;/* <<< Use Configuration Wizard in Context Menu >>> */
;/*****************************************************************************/
;/* This file is part of the uVision/ARM development tools. */
;/* Copyright (c) 2005-2007 Keil Software. All rights reserved. */
;/* This software may only be used under the terms of a valid, current, */
;/* end user licence from KEIL for a compatible version of KEIL software */
;/* development tools. Nothing else gives you the right to use this software. */
;/*****************************************************************************/
;/*
; * The STARTUP.S code is executed after CPU Reset. This file may be
; * translated with the following SET symbols. In uVision these SET
; * symbols are entered under Options - ASM - Define.
; *
; * REMAP: when set the startup code initializes the register MEMMAP
; * which overwrites the settings of the CPU configuration pins. The
; * startup and interrupt vectors are remapped from:
; * 0x00000000 default setting (not remapped)
; * 0x80000000 when EXTMEM_MODE is used
; * 0x40000000 when RAM_MODE is used
; *
; * EXTMEM_MODE: when set the device is configured for code execution
; * from external memory starting at address 0x80000000.
; *
; * RAM_MODE: when set the device is configured for code execution
; * from on-chip RAM starting at address 0x40000000.
; *
; * EXTERNAL_MODE: when set the PIN2SEL values are written that enable
; * the external BUS at startup.
; */
; Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs
Mode_USR EQU 0x10
Mode_FIQ EQU 0x11
Mode_IRQ EQU 0x12
Mode_SVC EQU 0x13
Mode_ABT EQU 0x17
Mode_UND EQU 0x1B
Mode_SYS EQU 0x1F
I_Bit EQU 0x80 ; when I bit is set, IRQ is disabled
F_Bit EQU 0x40 ; when F bit is set, FIQ is disabled
;// <h> Stack Configuration (Stack Sizes in Bytes)
;// <o0> Undefined Mode <0x0-0xFFFFFFFF:8>
;// <o1> Supervisor Mode <0x0-0xFFFFFFFF:8>
;// <o2> Abort Mode <0x0-0xFFFFFFFF:8>
;// <o3> Fast Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o4> Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o5> User/System Mode <0x0-0xFFFFFFFF:8>
;// </h>
UND_Stack_Size EQU 0x00000000
SVC_Stack_Size EQU 0x00000008
ABT_Stack_Size EQU 0x00000000
FIQ_Stack_Size EQU 0x00000000
IRQ_Stack_Size EQU 0x00000080
USR_Stack_Size EQU 0x00000400
ISR_Stack_Size EQU (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \
FIQ_Stack_Size + IRQ_Stack_Size)
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE USR_Stack_Size
__initial_sp SPACE ISR_Stack_Size
Stack_Top
;// <h> Heap Configuration
;// <o> Heap Size (in Bytes) <0x0-0xFFFFFFFF>
;// </h>
Heap_Size EQU 0x00000000
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
; VPBDIV definitions
VPBDIV EQU 0xE01FC100 ; VPBDIV Address
;// <e> VPBDIV Setup
;// <i> Peripheral Bus Clock Rate
;// <o1.0..1> VPBDIV: VPB Clock
;// <0=> VPB Clock = CPU Clock / 4
;// <1=> VPB Clock = CPU Clock
;// <2=> VPB Clock = CPU Clock / 2
;// <o1.4..5> XCLKDIV: XCLK Pin
;// <0=> XCLK Pin = CPU Clock / 4
;// <1=> XCLK Pin = CPU Clock
;// <2=> XCLK Pin = CPU Clock / 2
;// </e>
VPBDIV_SETUP EQU 0
VPBDIV_Val EQU 0x00000000
; Phase Locked Loop (PLL) definitions
PLL_BASE EQU 0xE01FC080 ; PLL Base Address
PLLCON_OFS EQU 0x00 ; PLL Control Offset
PLLCFG_OFS EQU 0x04 ; PLL Configuration Offset
PLLSTAT_OFS EQU 0x08 ; PLL Status Offset
PLLFEED_OFS EQU 0x0C ; PLL Feed Offset
PLLCON_PLLE EQU (1<<0) ; PLL Enable
PLLCON_PLLC EQU (1<<1) ; PLL Connect
PLLCFG_MSEL EQU (0x1F<<0) ; PLL Multiplier
PLLCFG_PSEL EQU (0x03<<5) ; PLL Divider
PLLSTAT_PLOCK EQU (1<<10) ; PLL Lock Status
;// <e> PLL Setup
;// <o1.0..4> MSEL: PLL Multiplier Selection
;// <1-32><#-1>
;// <i> M Value
;// <o1.5..6> PSEL: PLL Divider Selection
;// <0=> 1 <1=> 2 <2=> 4 <3=> 8
;// <i> P Value
;// </e>
PLL_SETUP EQU 1
PLLCFG_Val EQU 0x00000024
; Memory Accelerator Module (MAM) definitions
MAM_BASE EQU 0xE01FC000 ; MAM Base Address
MAMCR_OFS EQU 0x00 ; MAM Control Offset
MAMTIM_OFS EQU 0x04 ; MAM Timing Offset
;// <e> MAM Setup
;// <o1.0..1> MAM Control
;// <0=> Disabled
;// <1=> Partially Enabled
;// <2=> Fully Enabled
;// <i> Mode
;// <o2.0..2> MAM Timing
;// <0=> Reserved <1=> 1 <2=> 2 <3=> 3
;// <4=> 4 <5=> 5 <6=> 6 <7=> 7
;// <i> Fetch Cycles
;// </e>
MAM_SETUP EQU 1
MAMCR_Val EQU 0x00000002
MAMTIM_Val EQU 0x00000004
; External Memory Controller (EMC) definitions
EMC_BASE EQU 0xFFE00000 ; EMC Base Address
BCFG0_OFS EQU 0x00 ; BCFG0 Offset
BCFG1_OFS EQU 0x04 ; BCFG1 Offset
BCFG2_OFS EQU 0x08 ; BCFG2 Offset
BCFG3_OFS EQU 0x0C ; BCFG3 Offset
;// <e> External Memory Controller (EMC)
EMC_SETUP EQU 0
;// <e> Bank Configuration 0 (BCFG0)
;// <o1.0..3> IDCY: Idle Cycles <0-15>
;// <o1.5..9> WST1: Wait States 1 <0-31>
;// <o1.11..15> WST2: Wait States 2 <0-31>
;// <o1.10> RBLE: Read Byte Lane Enable
;// <o1.26> WP: Write Protect
;// <o1.27> BM: Burst ROM
;// <o1.28..29> MW: Memory Width <0=> 8-bit <1=> 16-bit
;// <2=> 32-bit <3=> Reserved
;// </e>
BCFG0_SETUP EQU 0
BCFG0_Val EQU 0x0000FBEF
;// <e> Bank Configuration 1 (BCFG1)
;// <o1.0..3> IDCY: Idle Cycles <0-15>
;// <o1.5..9> WST1: Wait States 1 <0-31>
;// <o1.11..15> WST2: Wait States 2 <0-31>
;// <o1.10> RBLE: Read Byte Lane Enable
;// <o1.26> WP: Write Protect
;// <o1.27> BM: Burst ROM
;// <o1.28..29> MW: Memory Width <0=> 8-bit <1=> 16-bit
;// <2=> 32-bit <3=> Reserved
;// </e>
BCFG1_SETUP EQU 0
BCFG1_Val EQU 0x0000FBEF
;// <e> Bank Configuration 2 (BCFG2)
;// <o1.0..3> IDCY: Idle Cycles <0-15>
;// <o1.5..9> WST1: Wait States 1 <0-31>
;// <o1.11..15> WST2: Wait States 2 <0-31>
;// <o1.10> RBLE: Read Byte Lane Enable
;// <o1.26> WP: Write Protect
;// <o1.27> BM: Burst ROM
;// <o1.28..29> MW: Memory Width <0=> 8-bit <1=> 16-bit
;// <2=> 32-bit <3=> Reserved
;// </e>
BCFG2_SETUP EQU 0
BCFG2_Val EQU 0x0000FBEF
;// <e> Bank Configuration 3 (BCFG3)
;// <o1.0..3> IDCY: Idle Cycles <0-15>
;// <o1.5..9> WST1: Wait States 1 <0-31>
;// <o1.11..15> WST2: Wait States 2 <0-31>
;// <o1.10> RBLE: Read Byte Lane Enable
;// <o1.26> WP: Write Protect
;// <o1.27> BM: Burst ROM
;// <o1.28..29> MW: Memory Width <0=> 8-bit <1=> 16-bit
;// <2=> 32-bit <3=> Reserved
;// </e>
BCFG3_SETUP EQU 0
BCFG3_Val EQU 0x0000FBEF
;// </e> End of EMC
; External Memory Pins definitions
PINSEL2 EQU 0xE002C014 ; PINSEL2 Address
PINSEL2_Val EQU 0x0E6149E4 ; CS0..3, OE, WE, BLS0..3,
; D0..31, A2..23, JTAG Pins
PRESERVE8
; Area Definition and Entry Point
; Startup Code must be linked first at Address at which it expects to run.
AREA RESET, CODE, READONLY
ARM
; Exception Vectors
; Mapped to Address 0.
; Absolute addressing mode must be used.
; Dummy Handlers are implemented as infinite loops which can be modified.
Vectors LDR PC, Reset_Addr
LDR PC, Undef_Addr
LDR PC, SWI_Addr
LDR PC, PAbt_Addr
LDR PC, DAbt_Addr
NOP ; Reserved Vector
; LDR PC, IRQ_Addr
LDR PC, [PC, #-0x0FF0] ; Vector from VicVectAddr
LDR PC, FIQ_Addr
Reset_Addr DCD Reset_Handler
Undef_Addr DCD Undef_Handler
SWI_Addr DCD SWI_Handler
PAbt_Addr DCD PAbt_Handler
DAbt_Addr DCD DAbt_Handler
DCD 0 ; Reserved Address
IRQ_Addr DCD IRQ_Handler
FIQ_Addr DCD FIQ_Handler
Undef_Handler B Undef_Handler
SWI_Handler B SWI_Handler
PAbt_Handler B PAbt_Handler
DAbt_Handler B DAbt_Handler
IRQ_Handler B IRQ_Handler
FIQ_Handler B FIQ_Handler
; Reset Handler
EXPORT Reset_Handler
Reset_Handler
; Setup External Memory Pins
IF :DEF:EXTERNAL_MODE
LDR R0, =PINSEL2
LDR R1, =PINSEL2_Val
STR R1, [R0]
ENDIF
; Setup External Memory Controller
IF EMC_SETUP <> 0
LDR R0, =EMC_BASE
IF BCFG0_SETUP <> 0
LDR R1, =BCFG0_Val
STR R1, [R0, #BCFG0_OFS]
ENDIF
IF BCFG1_SETUP <> 0
LDR R1, =BCFG1_Val
STR R1, [R0, #BCFG1_OFS]
ENDIF
IF BCFG2_SETUP <> 0
LDR R1, =BCFG2_Val
STR R1, [R0, #BCFG2_OFS]
ENDIF
IF BCFG3_SETUP <> 0
LDR R1, =BCFG3_Val
STR R1, [R0, #BCFG3_OFS]
ENDIF
ENDIF ; EMC_SETUP
; Setup VPBDIV
IF VPBDIV_SETUP <> 0
LDR R0, =VPBDIV
LDR R1, =VPBDIV_Val
STR R1, [R0]
ENDIF
; Setup PLL
IF PLL_SETUP <> 0
LDR R0, =PLL_BASE
MOV R1, #0xAA
MOV R2, #0x55
; Configure and Enable PLL
MOV R3, #PLLCFG_Val
STR R3, [R0, #PLLCFG_OFS]
MOV R3, #PLLCON_PLLE
STR R3, [R0, #PLLCON_OFS]
STR R1, [R0, #PLLFEED_OFS]
STR R2, [R0, #PLLFEED_OFS]
; Wait until PLL Locked
PLL_Loop LDR R3, [R0, #PLLSTAT_OFS]
ANDS R3, R3, #PLLSTAT_PLOCK
BEQ PLL_Loop
; Switch to PLL Clock
MOV R3, #(PLLCON_PLLE:OR:PLLCON_PLLC)
STR R3, [R0, #PLLCON_OFS]
STR R1, [R0, #PLLFEED_OFS]
STR R2, [R0, #PLLFEED_OFS]
ENDIF ; PLL_SETUP
; Setup MAM
IF MAM_SETUP <> 0
LDR R0, =MAM_BASE
MOV R1, #MAMTIM_Val
STR R1, [R0, #MAMTIM_OFS]
MOV R1, #MAMCR_Val
STR R1, [R0, #MAMCR_OFS]
ENDIF ; MAM_SETUP
; Memory Mapping (when Interrupt Vectors are in RAM)
MEMMAP EQU 0xE01FC040 ; Memory Mapping Control
IF :DEF:REMAP
LDR R0, =MEMMAP
IF :DEF:EXTMEM_MODE
MOV R1, #3
ELIF :DEF:RAM_MODE
MOV R1, #2
ELSE
MOV R1, #1
ENDIF
STR R1, [R0]
ENDIF
; Initialise Interrupt System
; ...
; Setup Stack for each mode
LDR R0, =Stack_Top
; Enter Undefined Instruction Mode and set its Stack Pointer
MSR CPSR_c, #Mode_UND:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #UND_Stack_Size
; Enter Abort Mode and set its Stack Pointer
MSR CPSR_c, #Mode_ABT:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #ABT_Stack_Size
; Enter FIQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_FIQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #FIQ_Stack_Size
; Enter IRQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #IRQ_Stack_Size
; Enter Supervisor Mode and set its Stack Pointer
MSR CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #SVC_Stack_Size
; Enter User Mode and set its Stack Pointer
MSR CPSR_c, #Mode_USR
IF :DEF:__MICROLIB
EXPORT __initial_sp
ELSE
MOV SP, R0
SUB SL, SP, #USR_Stack_Size
ENDIF
; Enter the C code
IMPORT __main
LDR R0, =__main
BX R0
IF :DEF:__MICROLIB
EXPORT __heap_base
EXPORT __heap_limit
ELSE
; User Initial Stack & Heap
AREA |.text|, CODE, READONLY
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
LDR R0, = Heap_Mem
LDR R1, =(Stack_Mem + USR_Stack_Size)
LDR R2, = (Heap_Mem + Heap_Size)
LDR R3, = Stack_Mem
BX LR
ENDIF
END
Unfortunately I am just starting to learn assembly, so I have no idea what this code does, but more important how to fix the problem. Here problematic line
; Enter the C code
IMPORT __main
LDR R0, =__main
BX R0
IF :DEF:__MICROLIB
EXPORT __heap_base
EXPORT __heap_limit
ELSE
As I can guess here main function is being called, but as far as I am writing assembly program, it throws me an error that I have no section main.
What is the correct way to start execution of my custom code from this startup.
I know that I can name my area RESET and it will goes here, but I want to do this in right way.
Thank you.
UPDATE
This code works just fine
AREA Factorial, CODE, READONLY
EXPORT __main
ENTRY
__main
MOV r0, #10 ; load initial value
MOV r1, #1 ; if n=0 than 1 is result
loop CMP r0, #0 ; if n=0
MULGT r1, r0, r1
SUBGT r0, r0, #1
BGT loop
stop B stop ; stop program
END
Thank you But only one warning
.\Objects\SortingAlgorithm.sct(8): warning: L6314W: No section matches pattern *(InRoot$$Sections).
Actually all that code is used to initialize the processor (set a stack for your push/pop operations, set vector for exceptions, clocks...) and initialize the "C" runtime (prepare a heap, initialize the variables for the runtime etc), but in general you can forget about these things. Please note that Nevertheless, all the programs in "C" starts with a function called "main" or really "_main", so that piece of code is looking for a symbol called on that way.
If you get your example code and declare a public label called "_main", you should be able to execute your code when your target (your board) boots!
So, something like that should make it work:
AREA Prog1, CODE, READONLY
EXPORT __main
; ENTRY <= You do not need to declare an entry point
__main
MOV r0, #0x11 ; load initial value
LSL r1, r0, #1 ; shift 1 bit left
LSL r2, r1, #1 ; shift 1 bit left
stop B stop ; stop program
END
Please note that I did not test that code! But as an starting point you can start with this.
Regards