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|
;/***************************************************************************
; * Copyright (c) 2024 Microsoft Corporation
; *
; * This program and the accompanying materials are made available under the
; * terms of the MIT License which is available at
; * https://opensource.org/licenses/MIT.
; *
; * SPDX-License-Identifier: MIT
; **************************************************************************/
;
;
;/**************************************************************************/
;/**************************************************************************/
;/** */
;/** ThreadX Component */
;/** */
;/** Initialize */
;/** */
;/**************************************************************************/
;/**************************************************************************/
;
;
;#define TX_SOURCE_CODE
;
;
;/* Include necessary system files. */
;
;#include "tx_api.h"
;#include "tx_initialize.h"
;#include "tx_thread.h"
;#include "tx_timer.h"
;
;
SVC_MODE EQU 0xD3 ; Disable IRQ/FIQ SVC mode
IRQ_MODE EQU 0xD2 ; Disable IRQ/FIQ IRQ mode
FIQ_MODE EQU 0xD1 ; Disable IRQ/FIQ FIQ mode
SYS_MODE EQU 0xDF ; Disable IRQ/FIQ SYS mode
HEAP_SIZE EQU 4096 ; Heap size
FIQ_STACK_SIZE EQU 512 ; FIQ stack size
SYS_STACK_SIZE EQU 1024 ; SYS stack size (used for nested interrupts)
IRQ_STACK_SIZE EQU 1024 ; IRQ stack size
;
;
;/* ARM9 ARMulator Timer and Interrupt controller information. This depends on
; the ARMulator's Interrupt Controller and Timer being enabled in the default.ami.
; In addition, the addresses must match those specified in the peripherals.ami file.
; Please refer to section 2.10 and 4.16 of the Debug Target Guide, version 1.2. */
;
IRQStatus EQU 0x0a000000 ; IRQ Status Register
IRQRawStatus EQU 0x0a000004 ; IRQ Raw Status Register
IRQEnable EQU 0x0a000008 ; IRQ Enable Set Register
IRQEnableClear EQU 0x0a00000C ; IRQ Enable Clear Register
IRQSoft EQU 0x0a000010 ; IRQ Soft
FIQStatus EQU 0x0a000100 ; FIQ Status Register
FIQRawStatus EQU 0x0a000104 ; FIQ Raw Status Register
FIQEnable EQU 0x0a000108 ; FIQ Enable Set Register
FIQEnableClear EQU 0x0a00010C ; FIQ Enable Clear Register
TIMER1_BIT EQU 0x00000010 ; IRQ/FIQ Timer1 bit
TIMER2_BIT EQU 0x00000020 ; IRQ/FIQ Timer2 bit
Timer1Load EQU 0x0a800000 ; Timer1 Load Register
Timer1Value EQU 0x0a800004 ; Timer1 Value Register
Timer1Control EQU 0x0a800008 ; Timer1 Control Register
Timer1Clear EQU 0x0a80000C ; Timer1 Clear Register
Timer1Mode EQU 0x000000C0 ; Timer1 Control Value, Timer enable, periodic, no prescaler
Timer1Period EQU 0x0000FFFF ; Timer1 count-down period, maximum value
Timer2Load EQU 0x0a800020 ; Timer2 Load Register
Timer2Value EQU 0x0a800024 ; Timer2 Value Register
Timer2Control EQU 0x0a800028 ; Timer2 Control Register
Timer2Clear EQU 0x0a80002C ; Timer2 Clear Register
;
;
IMPORT _tx_thread_system_stack_ptr
IMPORT _tx_initialize_unused_memory
IMPORT _tx_thread_context_save
IMPORT _tx_thread_context_restore
IF :DEF:TX_ENABLE_FIQ_SUPPORT
IMPORT _tx_thread_fiq_context_save
IMPORT _tx_thread_fiq_context_restore
ENDIF
IF :DEF:TX_ENABLE_IRQ_NESTING
IMPORT _tx_thread_irq_nesting_start
IMPORT _tx_thread_irq_nesting_end
ENDIF
IF :DEF:TX_ENABLE_FIQ_NESTING
IMPORT _tx_thread_fiq_nesting_start
IMPORT _tx_thread_fiq_nesting_end
ENDIF
IMPORT _tx_timer_interrupt
IMPORT __main
IMPORT _tx_version_id
IMPORT _tx_build_options
IMPORT |Image$$ZI$$Limit|
;
;
AREA Init, CODE, READONLY
;
;/* Define the ARM9 vector area. This should be located or copied to 0. */
;
EXPORT __vectors
__vectors
LDR pc,=__main ; Reset goes to startup function
LDR pc,=__tx_undefined ; Undefined handler
LDR pc,=__tx_swi_interrupt ; Software interrupt handler
LDR pc,=__tx_prefetch_handler ; Prefetch exception handler
LDR pc,=__tx_abort_handler ; Abort exception handler
LDR pc,=__tx_reserved_handler ; Reserved exception handler
LDR pc,=__tx_irq_handler ; IRQ interrupt handler
LDR pc,=__tx_fiq_handler ; FIQ interrupt handler
;
;
AREA ||.text||, CODE, READONLY
;/**************************************************************************/
;/* */
;/* FUNCTION RELEASE */
;/* */
;/* _tx_initialize_low_level ARM9/AC5 */
;/* 6.1 */
;/* AUTHOR */
;/* */
;/* William E. Lamie, Microsoft Corporation */
;/* */
;/* DESCRIPTION */
;/* */
;/* This function is responsible for any low-level processor */
;/* initialization, including setting up interrupt vectors, setting */
;/* up a periodic timer interrupt source, saving the system stack */
;/* pointer for use in ISR processing later, and finding the first */
;/* available RAM memory address for tx_application_define. */
;/* */
;/* INPUT */
;/* */
;/* None */
;/* */
;/* OUTPUT */
;/* */
;/* None */
;/* */
;/* CALLS */
;/* */
;/* None */
;/* */
;/* CALLED BY */
;/* */
;/* _tx_initialize_kernel_enter ThreadX entry function */
;/* */
;/**************************************************************************/
;VOID _tx_initialize_low_level(VOID)
;{
EXPORT _tx_initialize_low_level
_tx_initialize_low_level
;
;
; /****** NOTE ****** We must be in SVC MODE at this point. Some monitors
; enter this routine in USER mode and require a software interrupt to
; change into SVC mode. */
;
LDR r1, =|Image$$ZI$$Limit| ; Get end of non-initialized RAM area
LDR r2, =HEAP_SIZE ; Pickup the heap size
ADD r1, r2, r1 ; Setup heap limit
ADD r1, r1, #4 ; Setup stack limit
;
IF :DEF:TX_ENABLE_IRQ_NESTING
; /* Setup the system mode stack for nested interrupt support */
LDR r2, =SYS_STACK_SIZE ; Pickup stack size
MOV r3, #SYS_MODE ; Build SYS mode CPSR
MSR CPSR_cxsf, r3 ; Enter SYS mode
ADD r1, r1, r2 ; Calculate start of SYS stack
BIC r1, r1, #7 ; Ensure 8-byte alignment
MOV sp, r1 ; Setup SYS stack pointer
ENDIF
;
LDR r2, =FIQ_STACK_SIZE ; Pickup stack size
MOV r0, #FIQ_MODE ; Build FIQ mode CPSR
MSR CPSR_c, r0 ; Enter FIQ mode
ADD r1, r1, r2 ; Calculate start of FIQ stack
BIC r1, r1, #7 ; Ensure 8-byte alignment
MOV sp, r1 ; Setup FIQ stack pointer
MOV sl, #0 ; Clear sl
MOV fp, #0 ; Clear fp
LDR r2, =IRQ_STACK_SIZE ; Pickup IRQ (system stack size)
MOV r0, #IRQ_MODE ; Build IRQ mode CPSR
MSR CPSR_c, r0 ; Enter IRQ mode
ADD r1, r1, r2 ; Calculate start of IRQ stack
BIC r1, r1, #7 ; Ensure 8-byte alignment
MOV sp, r1 ; Setup IRQ stack pointer
MOV r0, #SVC_MODE ; Build SVC mode CPSR
MSR CPSR_c, r0 ; Enter SVC mode
LDR r3, =_tx_thread_system_stack_ptr ; Pickup stack pointer
STR r1, [r3, #0] ; Save the system stack
;
; /* Save the system stack pointer. */
; _tx_thread_system_stack_ptr = (VOID_PTR) (sp);
;
LDR r1, =_tx_thread_system_stack_ptr ; Pickup address of system stack ptr
LDR r0, [r1, #0] ; Pickup system stack
ADD r0, r0, #4 ; Increment to next free word
;
; /* Save the first available memory address. */
; _tx_initialize_unused_memory = (VOID_PTR) |Image$$ZI$$Limit| + HEAP + [SYS_STACK] + FIQ_STACK + IRQ_STACK;
;
LDR r2, =_tx_initialize_unused_memory ; Pickup unused memory ptr address
STR r0, [r2, #0] ; Save first free memory address
;
; /* Setup Timer for periodic interrupts. */
;
; /* Setup ARMulator Timer1 for periodic interrupts. */
;
LDR r0,=IRQEnable ; Build address of IRQ enable register
LDR r1,=TIMER1_BIT ; Build value of Timer1 IRQ enable
STR r1,[r0] ; Enable IRQ interrupts for Timer1
LDR r0,=Timer1Load ; Build address of Timer1 load register
LDR r1,=Timer1Period ; Build Timer1 periodic value
STR r1,[r0] ; Set Timer1 load value
LDR r0,=Timer1Control ; Build address of Timer1 control register
LDR r1,=Timer1Mode ; Build Timer1 control value
STR r1,[r0] ; Enable Timer1
;
; /* Done, return to caller. */
;
IF {INTER} = {TRUE}
BX lr ; Return to caller
ELSE
MOV pc, lr ; Return to caller
ENDIF
;}
;
;
;/* Define initial heap/stack routine for the ARM RealView (and ADS) startup code. This
; routine will set the initial stack to use the ThreadX IRQ & FIQ &
; (optionally SYS) stack areas. */
;
EXPORT __user_initial_stackheap
__user_initial_stackheap
LDR r0, =|Image$$ZI$$Limit| ; Get end of non-initialized RAM area
LDR r2, =HEAP_SIZE ; Pickup the heap size
ADD r2, r2, r0 ; Setup heap limit
ADD r3, r2, #4 ; Setup stack limit
MOV r1, r3 ; Setup start of stack
IF :DEF:TX_ENABLE_IRQ_NESTING
LDR r12, =SYS_STACK_SIZE ; Pickup IRQ system stack
ADD r1, r1, r12 ; Setup the return system stack
BIC r1, r1, #7 ; Ensure 8-byte alignment
ENDIF
LDR r12, =FIQ_STACK_SIZE ; Pickup FIQ stack size
ADD r1, r1, r12 ; Setup the return system stack
BIC r1, r1, #7 ; Ensure 8-byte alignment
LDR r12, =IRQ_STACK_SIZE ; Pickup IRQ system stack
ADD r1, r1, r12 ; Setup the return system stack
BIC r1, r1, #7 ; Ensure 8-byte alignment
IF {INTER} = {TRUE}
BX lr ; Return to caller
ELSE
MOV pc, lr ; Return to caller
ENDIF
;
;
;/* Define shells for each of the interrupt vectors. */
;
EXPORT __tx_undefined
__tx_undefined
B __tx_undefined ; Undefined handler
;
EXPORT __tx_swi_interrupt
__tx_swi_interrupt
B __tx_swi_interrupt ; Software interrupt handler
;
EXPORT __tx_prefetch_handler
__tx_prefetch_handler
B __tx_prefetch_handler ; Prefetch exception handler
;
EXPORT __tx_abort_handler
__tx_abort_handler
B __tx_abort_handler ; Abort exception handler
;
EXPORT __tx_reserved_handler
__tx_reserved_handler
B __tx_reserved_handler ; Reserved exception handler
;
;
EXPORT __tx_irq_handler
EXPORT __tx_irq_processing_return
__tx_irq_handler
;
; /* Jump to context save to save system context. */
B _tx_thread_context_save
__tx_irq_processing_return
;
; /* At this point execution is still in the IRQ mode. The CPSR, point of
; interrupt, and all C scratch registers are available for use. In
; addition, IRQ interrupts may be re-enabled - with certain restrictions -
; if nested IRQ interrupts are desired. Interrupts may be re-enabled over
; small code sequences where lr is saved before enabling interrupts and
; restored after interrupts are again disabled. */
;
;
; /* Check for Timer1 interrupts on the ARMulator. */
LDR r1,=IRQStatus ; Pickup address of IRQStatus register
LDR r2, [r1] ; Read IRQStatus
LDR r0,=TIMER1_BIT ; Pickup Timer1 interrupt present bit
AND r2, r2, r0 ; Is this a timer interrupt?
CMP r2, r0 ;
BNE _tx_not_timer_interrupt ; If 0, not a timer interrupt
LDR r1,=Timer1Clear ; Build address of Timer1 clear register
MOV r0,#0 ;
STR r0, [r1] ; Clear timer 0 interrupt
BL _tx_timer_interrupt ; Timer interrupt handler
_tx_not_timer_interrupt
;
; /* Interrupt nesting is allowed after calling _tx_thread_irq_nesting_start
; from IRQ mode with interrupts disabled. This routine switches to the
; system mode and returns with IRQ interrupts enabled.
;
; NOTE: It is very important to ensure all IRQ interrupts are cleared
; prior to enabling nested IRQ interrupts. */
IF :DEF:TX_ENABLE_IRQ_NESTING
BL _tx_thread_irq_nesting_start
ENDIF
;
;
; /* Application IRQ handlers can be called here! */
;
; /* If interrupt nesting was started earlier, the end of interrupt nesting
; service must be called before returning to _tx_thread_context_restore.
; This routine returns in processing in IRQ mode with interrupts disabled. */
IF :DEF:TX_ENABLE_IRQ_NESTING
BL _tx_thread_irq_nesting_end
ENDIF
;
; /* Jump to context restore to restore system context. */
B _tx_thread_context_restore
;
;
; /* This is an example of a vectored IRQ handler. */
;
EXPORT __tx_example_vectored_irq_handler
__tx_example_vectored_irq_handler
;
;
; /* Save initial context and call context save to prepare for
; vectored ISR execution. */
;
; STMDB sp!, {r0-r3} ; Save some scratch registers
; MRS r0, SPSR ; Pickup saved SPSR
; SUB lr, lr, #4 ; Adjust point of interrupt
; STMDB sp!, {r0, r10, r12, lr} ; Store other scratch registers
; BL _tx_thread_vectored_context_save ; Vectored context save
;
; /* At this point execution is still in the IRQ mode. The CPSR, point of
; interrupt, and all C scratch registers are available for use. In
; addition, IRQ interrupts may be re-enabled - with certain restrictions -
; if nested IRQ interrupts are desired. Interrupts may be re-enabled over
; small code sequences where lr is saved before enabling interrupts and
; restored after interrupts are again disabled. */
;
;
; /* Interrupt nesting is allowed after calling _tx_thread_irq_nesting_start
; from IRQ mode with interrupts disabled. This routine switches to the
; system mode and returns with IRQ interrupts enabled.
;
; NOTE: It is very important to ensure all IRQ interrupts are cleared
; prior to enabling nested IRQ interrupts. */
; IF :DEF:TX_ENABLE_IRQ_NESTING
; BL _tx_thread_irq_nesting_start
; ENDIF
;
; /* Application IRQ handlers can be called here! */
;
; /* If interrupt nesting was started earlier, the end of interrupt nesting
; service must be called before returning to _tx_thread_context_restore.
; This routine returns in processing in IRQ mode with interrupts disabled. */
; IF :DEF:TX_ENABLE_IRQ_NESTING
; BL _tx_thread_irq_nesting_end
; ENDIF
;
; /* Jump to context restore to restore system context. */
; B _tx_thread_context_restore
;
;
IF :DEF:TX_ENABLE_FIQ_SUPPORT
EXPORT __tx_fiq_handler
EXPORT __tx_fiq_processing_return
__tx_fiq_handler
;
; /* Jump to fiq context save to save system context. */
B _tx_thread_fiq_context_save
__tx_fiq_processing_return
;
; /* At this point execution is still in the FIQ mode. The CPSR, point of
; interrupt, and all C scratch registers are available for use. */
;
; /* Interrupt nesting is allowed after calling _tx_thread_fiq_nesting_start
; from FIQ mode with interrupts disabled. This routine switches to the
; system mode and returns with FIQ interrupts enabled.
;
; NOTE: It is very important to ensure all FIQ interrupts are cleared
; prior to enabling nested FIQ interrupts. */
IF :DEF:TX_ENABLE_FIQ_NESTING
BL _tx_thread_fiq_nesting_start
ENDIF
;
; /* Application FIQ handlers can be called here! */
;
; /* If interrupt nesting was started earlier, the end of interrupt nesting
; service must be called before returning to _tx_thread_fiq_context_restore. */
IF :DEF:TX_ENABLE_FIQ_NESTING
BL _tx_thread_fiq_nesting_end
ENDIF
;
; /* Jump to fiq context restore to restore system context. */
B _tx_thread_fiq_context_restore
;
;
ELSE
EXPORT __tx_fiq_handler
__tx_fiq_handler
B __tx_fiq_handler ; FIQ interrupt handler
ENDIF
;
; /* Reference build options and version ID to ensure they come in. */
;
LDR r2, =_tx_build_options ; Pickup build options variable address
LDR r0, [r2, #0] ; Pickup build options content
LDR r2, =_tx_version_id ; Pickup version ID variable address
LDR r0, [r2, #0] ; Pickup version ID content
;
;
END
|
