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: 1.9.6.1 $        ;   $Author: rivimey $        ;     $Date: 1997/12/10 18:50:22 $        ;        ; 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        ; ---------------------------------------------------------------------        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  |__entry|                     ; 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_Yield|        IMPORT  |Angel_EnterSVC|        IMPORT  |Angel_ExitToUSR|        IMPORT  |Angel_InitialiseTaskFinished|        IMPORT  |Angel_BlockApplication|        IMPORT  |Angel_StackBase|                ; ---------------------------------------------------------------------        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 :OR: IRQDisable :OR: FIQDisable        MSR     CPSR_cxsf, a1                ADD     sp, a2, #Angel_AngelStackOffset        ADD     sl, a2, #Angel_AngelStackLimitOffset        MOV     fp, #0x00000000        IF :DEF: JTAG_ADP_SUPPORTED          IF JTAG_ADP_SUPPORTED <> 0            B       __entry                        EXPORT |main|main          ENDIF        ENDIF                ; 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        ;        ;        ; 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.        ;NoDeviceSupportNoChannelSupport        BL      Angel_EnterSVC        BL      Angel_ExitToUSR ; This will reenable interrupts !  IF :DEF: MINIMAL_ANGEL :LAND: MINIMAL_ANGEL<>0        ; We just jump straight to the application's __entry point        BL      __entryAppFinished        ADR     a1, appexitmsg        B       __rt_asm_fatalerrorappexitmsg        DCB     "Appl returned\n"        ALIGN  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.        LDR     a1,=angel_BootInit  ; check that boot agent exists        TEQ     a1,#0x00000000      ; if zero, it does not exist        BLNE    angel_BootInit      ; deal with starting bootstrap agent        IF :DEF: LATE_STARTUP :LAND: LATE_STARTUP <> 0          ; We're doing late startup, so as long as there is an entry point,          ; simply unblock the application, and call Yield to let it run                  LDR     a1,=__entry          TEQ     a1,#0x00000000          BEQ     No__entry          BL      Angel_InitialiseTaskFinished          MOV     r0, #0        ; unblock          BL      Angel_BlockApplication          BL      Angel_YieldAppDidNotRun          B       AppDidNotRun  ; should never get here        No__entry          ;; If it doesn't exist, we drop through                ENDIF                BL      Angel_InitialiseTaskFinished        ;; Shouldn't get here more than once        BlockingLoop        BL      Angel_Yield        B       BlockingLoop  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    |Angel$$DATA|,DATA,NOINIT        EXPORT  angel_StartupStatus        EXPORT  angel_MMUtypeangel_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