TTL Generic ARM start-of-day (initialisation) code > startlib.s ; --------------------------------------------------------------------- ; This file provides the Angel initialisation and startup code ; for library based systems. It is also the entry point for ; the C-Library. After the initialisation, the start-up ; routine "_main" is called. ; ; The source file "startrom.s" provides the Angel startup code ; for ROM based versions of Angel, which eventually calls this ; code to start Angel and the application. ; ; $Revision: 1.12.2.3 $ ; $Author: rivimey $ ; $Date: 1998/10/15 17:12:31 $ ; ; Copyright Advanced RISC Machines Limited, 1995. ; All Rights Reserved ; --------------------------------------------------------------------- GET listopts.s ; standard listing control GET lolevel.s ; automatically built manifest definitions GET macros.s ; standard assembler support GET target.s ; target specific manifests GET taskmacs.s ; --------------------------------------------------------------------- EXPORT |__main| ; Angel startup entry point (non-APCS) IMPORT |__rt_asm_fatalerror| ; error reporting via suppasm.s IMPORT |angel_ExceptionInit|,WEAK ; exception handler initialisation IMPORT |angel_InitialiseDevices|,WEAK ; device driver initialisation IMPORT |angel_InitialiseChannels|,WEAK ; channel initialisation IMPORT |Angel_ProfileTimerInitialise|,WEAK ; profile & yield timer IMPORT |angel_BootInit|,WEAK ; bootstrap agent initialisation IMPORT |angel_DebugInit|,WEAK ; debugging support initialisation IMPORT |angelOS_Initialise|,WEAK ; OS debug support initialisation IMPORT |angel_SysLibraryInit|,WEAK ; CLib support initialisation IF :DEF: MINIMAL_ANGEL :LAND: MINIMAL_ANGEL<>0 IMPORT |Angel_RawDeviceControl|,WEAK ; ---"--- IMPORT |__centry| ; Application entry point ELSE IMPORT |angel_DeviceControl|,WEAK ; Used to set the LED on the card IMPORT |__entry|,WEAK ; Application entry point ENDIF IMPORT |Angel_NewTask| IMPORT |angel_SetPriority| IMPORT |Angel_Yield| IMPORT |Angel_EnterSVC| IMPORT |Angel_ExitToUSR| IMPORT |Angel_InitialiseTaskFinished| IMPORT |Angel_BlockApplication| IMPORT |angel_SelectNextTask| IMPORT |Angel_StackBase| IMPORT Angel_EnableInterruptsFromUSR ; --------------------------------------------------------------------- AREA |C$$Code$$Startup|,CODE,READONLY |__main| ; in: SVC mode; IRQs and FIQs disabled. ; r13 = FD stack ; out: Exits via the |_main| routine. ; ; Setup an APCS register state before calling any of the initialisation ; routines. We also want to be in USR mode, with the Angel stack ; in use. However we want to keep interrupts disabled too, which is ; unusual (normally USR mode => IRQ and FIQ enabled). ; LDR a2, =Angel_StackBase LDR a2, [a2] ADD sp, a2, #Angel_SVCStackOffset ; Reset the SVC stack MOV a1, #USRmode + InterruptMask MSR CPSR_cf, a1 ADD sp, a2, #Angel_AngelStackOffset IF :DEF: R10_IS_SL ADD sl, a2, #Angel_AngelStackLimitOffset ENDIF MOV fp, #0x00000000 ; This is the main C-Library and Angel startup point. The ; Angel world and the library are initialised, before calling ; the application. NOTE: In a ROM only monitor world, the ; application is a simple control loop managing debug messages ; from the host. However for normal applications, or ROM based ; applications the code called will be the user code. This ; file does not expect any other interface, other than when ; the initialisation is complete the routine "_main" will be ; called to enter the application "main" routine. ; ; This code *IS* single threaded. When Angel is being ; constructed as part of a multi-threaded application, then ; this initialisation code should be atomic. At the moment ; this is achieved by ensuring that this code is entered in ; SVC mode with processor interrupts disabled. If part of a ; ROM image, then the ROM boot-strapping code will ensure that ; this routine is entered with the correct mode and ; status. Similarly the new Angel run-time specifies that ; applications are always entered through |__main| in SVC mode ; with processor interrupts disabled. The run-time library ; then deals with switching to USR mode after its ; initialisation, and before starting the application. This is ; different from the old Demon method of always starting new ; applications in USR mode, but does allow applications in the ; new Angel world to have suitable priviledged control. This ; avoids the Angel run-time from having to know anything about ; the environment that started the Angel application, which in ; itself need *NOT* be based on Angel. ; ; This routine contains the generic Angel initialisation. Any ; ROM specific boot-strapping is held in the "startrom.s" ; source file. ; LDR a1,=angel_ExceptionInit ; get address of function TEQ a1,#0x00000000 ; if zero, it does not exist BLNE angel_ExceptionInit ; initialise the exception system IF :DEF: INCLUDE_FPASC ; Initialise the FPASC (AFTER setting up the vectors!) BL Angel_EnterSVC LDR r0, =FPASC_Initialised MOV r1, #0 STR r1, [r0] IMPORT FPASC_STARTUP BL FPASC_STARTUP LDR r0, =FPASC_Initialised MOV r1, #1 ; FPASC says everything is OK STR r1, [r0] ; If anything goes wrong, just leave the 'initialised' flag at 0. EXPORT COREFAULTY EXPORT COREDISABLED EXPORT FPA_ABSENT COREFAULTY COREDISABLED FPA_ABSENT ; Flatten the stack in case the FPASC found a fault ; NB Reset to the USER stack base, as state change will swap back LDR sp, =Angel_StackBase+Angel_AngelStackOffset BL Angel_ExitToUSR ENDIF ; ; ; The following calls should probably be build-time ; conditional. The Angel library being constructed may not ; require the device driver support, or any debug channel ; support. At the moment we just include run-time checks for ; the relevant functions being available. ; LDR a1,=angel_InitialiseDevices ; get address of function TEQ a1,#0x00000000 ; if zero, it does not exist BEQ NoDeviceSupport ; cannot have comms support ; BL angel_InitialiseDevices ; init device driver world ; ; Now set the LED which is attached to one of the real devices ; IF :DEF: MINIMAL_ANGEL :LAND: MINIMAL_ANGEL<>0 LDR a1,=Angel_RawDeviceControl ELSE LDR a1,=angel_DeviceControl ENDIF TEQ a1, #0 BEQ NoDevicesSoNoLEDs ; MOV a1, #DI_LED_DEVICE MOV a2, #DC_SET_LED MOV a3, #1 ; IF :DEF: MINIMAL_ANGEL :LAND: MINIMAL_ANGEL<>0 BL Angel_RawDeviceControl ELSE BL angel_DeviceControl ENDIF ; NoDevicesSoNoLEDs ; LDR a1,=angel_InitialiseChannels ; get address of function TEQ a1,#0x00000000 ; if zero, it does not exist BEQ NoChannelSupport ; cannot have comms support ; BL angel_InitialiseChannels ; initialise the channel world ; ; NOTE: There is no error status return from the device ; initialisation routine. This means that each device driver ; must keep its own active (and initialised OK) state, with ; the users of the device driver dealing with individual ; device driver error returns. ; LDR a1,=angel_DebugInit ; check for debug agent TEQ a1,#0x00000000 ; if zero, it does not exist BLNE angel_DebugInit ; initialise debugging world LDR a1,=angelOS_Initialise ; check for OS presence. TEQ a1,#0x00000000 ; if zero, it does not exist BLNE angelOS_Initialise ; initialise the OS. ; LDR a1,=angel_SysLibraryInit ; Check for C Library Support TEQ a1,#0x00000000 ; If zero, does not exist. BLNE angel_SysLibraryInit LDR a1,=Angel_ProfileTimerInitialise ; Check for Profile / Yield TEQ a1,#0x00000000 ; Timer Support BLNE Angel_ProfileTimerInitialise ; ; The Angel defined startup channels should now be initialised. ; NoDeviceSupport NoChannelSupport IF MINIMAL_ANGEL <> 0 BL Angel_EnableInterruptsFromUSR ; We just jump straight to the application's __entry point BL __centry AppFinished FatalError "Appl returned\n" ELSE ; The boot agent should be the last part of the communications ; system to be initialised, because it sends the first message ; to the host. The host should not be generating *ANY* ; messages until it has received the "booted" status message ; from the target. ; angel_TaskQueueItem * ; Angel_NewTask(unsigned fn, angel_TaskType type, bool yield, ; void *a1, void *a2, void *a3, void *a4) LDR r0, =angel_BootTask ; task addr MOV r1, #TP_AngelCallBack ; task type MOV r2, #0 ; yield MOV r3, #0 ; param a1 SUB sp, sp, #12 ; skip params 2-4 -- unneeded BL Angel_NewTask ADD sp, sp, #12 ; skip params 2-4 -- unneeded ; returns with r0 == TQI address ; store a name for the task in (tqi->name) ADR r1, boottaskname STR r1, [r0, #TQI_Name] ; Get into SVC with IRQ and FIQ disabled so we can call the serialiser LDR a1, =angel_SWIreason_EnterSVC SWI angel_SWI_ARM ; set svc_sp to the supervisor area too... SetStack Angel_SVCStackOffset ;; this will run the Angel Idle loop unless something else turns up. B angel_SelectNextTask boottaskname DCB "Boot Task",0 ALIGN ; --------------------------------------------------------------------- ; void angel_BootTask(void) angel_BootTask STMFD sp!, {lr} ; save LR LDR a1,=angel_BootInit ; check that boot agent exists TEQ a1,#0x0 ; if zero, it does not exist BL angel_BootInit ; deal with starting bootstrap agent BL Angel_InitialiseTaskFinished LDMFD sp!, {lr} ; save LR MOV pc, lr ; commit suicide; return to scheduler ENDIF ; ELSE not minimal angel ; --------------------------------------------------------------------- ; -- Angel run-time workspace ----------------------------------------- ; --------------------------------------------------------------------- ; Data areas should be declared as necessary. The old Demon source ; used assembler so no problem with C inter-working of the variables ; was required. However, the C-Demon work continued to use assembler ; "space" definitions. This meant a lot of "complicated" work when ; inter-working with the C portions of C-Demon. For Angel the simple ; approach of defining proper data AREAs in assembler, and ensuring ; that the C definitions are correct (to ensure data exists in the ; correct type of AREA) is used to ensure that clean assembler/C ; inter-working can occur. ; ; The following data area defines the layout of the Angel ; workspace. It does not specify where the work-space is ; placed in the final memory map. When Angel is being built as ; part of a ROM image, then the workspace lives at a fixed ; lo-memory address. When Angel is part of an application, ; then the workspace is placed in the standard application ; memory by the linker. This ensures that an Angel system ; loaded as part of an application is seperate to any version ; of Angel already present in a boot/debug ROM. AREA |AngelROM$$Data|,DATA,NOINIT EXPORT angel_StartupStatus EXPORT angel_MMUtype angel_LibraryWorkspaceStart % 0 ; start of this workspace section ; This is a status variable used to hold information on how ; Angel was started. For ROM systems this can include whether ; the system was started as a result of a PowerOnReset, or for ; library based systems it can be information on how the ; system was downloaded and initialised. Zero denotes a ; hard-reset, whilst a non-zero value denotes a soft-reset. angel_StartupStatus % 4 ; type of Angel reset ; This variable is used to denote whether the startup code ; discovered an ARM MMU unit. This is needed to ensure that ; certain routines can discover whether there is a cache ; present. i.e. memory sizing code needsd to ensure that the ; cache is disabled when checking for ghosting. angel_MMUtype % 4 ; type of MMU present angel_LibraryWorkspaceEnd % 0 ; allows size of area to be calculated ; --------------------------------------------------------------------- END ; EOF startlib.s