📄 cstartup.asm
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; (c)2002 by Texas Instruments Incorporated, All Rights Reserved.
;---------------------------------------------------------------;
; ;
; CSTARTUP.S03 ;
; ;
; ;
; This file has been modified for removing set port 2 all 0, ;
; this makes sure the port 2 is still input during reset. ;
; ;
; ;
; This module contains the entire code executed before the C ;
; "main" function is called. The code can be tailored to suit ;
; special hardware needs. The code is designed to run on any ;
; processor based on the 8051 architecture. ;
; ;
; Version: 5.20 [IMAF 960603] ;
;
; Revision control system
; $Revision: 1.19 $
;
;---------------------------------------------------------------;
NAME CSTARTUP
PUBLIC init_C
$DEFFN init_C(0400H,0,0,0,0,0,0,0)
$defmodel.inc ; Defines memory model
EXTERN ?C_EXIT ; Where to go when program is done
EXTERN _R ; Register bank (0, 8, 16 or 24)
EXTERN main ; First C function usually
$DEFFN main(32768,0,0,0)
EXTERN __low_level_init ; Setup low level things
$DEFFN __low_level_init(0,0,0,0)
EXTERN exit
$DEFFN exit(0,0,0,0)
IF banked_mode
EXTERN ?X_CALL_L18
ENDIF
RSEG B_UDATA
RSEG B_CDATA
RSEG B_IDATA
RSEG D_UDATA
RSEG D_CDATA
RSEG D_IDATA
RSEG I_UDATA
RSEG I_CDATA
RSEG I_IDATA
RSEG P_UDATA
RSEG P_CDATA
RSEG P_IDATA
IF lcall_mode
RSEG X_UDATA
RSEG X_CDATA
RSEG X_IDATA
RSEG ECSTR
RSEG CCSTR
ENDIF
;---------------------------------------------------------------;
; The C stack segment. Should be mapped into internal data RAM ;
;---------------------------------------------------------------;
; The C stack is used for LCALL's and temporary storage for ;
; code generator help-routines (math etc). The stack will be ;
; located after all other internal RAM variables if the stan- ;
; dard linking procedure is followed. Note that C interrupt ;
; routines can double stack size demands. ;
;---------------------------------------------------------------;
RSEG CSTACK
stack_begin:
DS 30 ; Increase if needed
COMMON INTVEC ; Should be at location zero
;---------------------------------------------------------------;
; C interrupt routines with defined [vectors] will reserve ;
; space in this area. So will handlers written in assembler if ;
; they follow the recommended format. ;
;---------------------------------------------------------------;
startup:
IF lcall_mode
LJMP init_C
ELSE
AJMP init_C
ENDIF
RSEG RCODE ; Should be loaded after INTVEC
init_C:
MOV SP,#stack_begin - 1 ; From low to high addresses
; 20001214 modified by lobo
; P_IDATA is not used and P2 can NOT be zero after power-on reset.
; All P Ports should be in input mode after power-on reset.
; MOV DPTR,#SFB (P_IDATA) ; Initialize high byte of PDATA.
; MOV P2,DPH ;
;----------------------------------------------------------------------
; Call __low_level_init to perform initialization before initializing
; segments and calling main. If the function returns 0 no segment
; initialization should take place.
;
; Link with your own version of __low_level_init to override the
; default action: to do nothing but return 1.
;----------------------------------------------------------------------
IF banked_mode
MOV A,#$BYTE3 __low_level_init
MOV DPTR,# LWRD(__low_level_init)
LCALL ?X_CALL_L18 ; main()
ELSE
IF lcall_mode
LCALL __low_level_init
ELSE
ACALL __low_level_init
ENDIF
ENDIF
MOV A,R4
ORL A,R5
JZ skip_init
;---------------------------------------------------------------;
; C variable initialization section ;
; ================================= ;
; ;
; If there is no demand that global/static C variables should ;
; have a defined value at startup (required by ANSI), the ;
; following section can be removed to conserve code memory ;
; size. Note that this part calls functions in the end of ;
; this file, that also can be removed if initialized values are ;
; not needed. ;
; ;
; Systems controlled by a watch-dog may require additional ;
; code insertions as the initialization can take several ;
; milliseconds (if there are many variables) to complete. ;
; These parts are marked with *** WDG *** ;
;---------------------------------------------------------------;
;===============================================================;
; Zero out sections containing variables without explicit ;
; initializers like in: ;
; ;
; int i; ;
; xdata double d[10]; ;
;===============================================================;
MOV R0,#SFE(I_UDATA)-1
SJMP CLEAR_IDATA_2
CLEAR_IDATA:
MOV @R0,#0
DEC R0
CLEAR_IDATA_2:
CJNE R0,#SFB(I_UDATA)-1,CLEAR_IDATA
MOV R0,#SFE(D_UDATA)-1
SJMP CLEAR_DDATA_2
CLEAR_DDATA:
MOV @R0,#0
DEC R0
CLEAR_DDATA_2:
CJNE R0,#SFB(D_UDATA)-1,CLEAR_DDATA
MOV R0,#SFE(B_UDATA)-1
SJMP CLEAR_BDATA_2
CLEAR_BDATA:
MOV @R0,#0
DEC R0
CLEAR_BDATA_2:
CJNE R0,#SFB(B_UDATA)-1,CLEAR_BDATA
IF lcall_mode
MOV DPTR,#SFE (X_UDATA) ; XDATA
MOV R6,DPH
MOV R7,DPL
MOV DPTR,#SFB (X_UDATA)
NEXT_X_UDATA:
LCALL COMP_R67_DPTR
JZ INIT_P_UDATA
CLR A
MOVX @DPTR,A
INC DPTR
SJMP NEXT_X_UDATA
INIT_P_UDATA:
MOV DPTR,#SFB (P_UDATA)
MOV R0,DPL
MOV DPTR,#SFE (P_UDATA)
MOV R1,DPL
NEXT_P_UDATA:
MOV A,R0
CLR C
SUBB A,R1
JNC INIT_VARS
MOV @R0,#0
INC R0
SJMP NEXT_P_UDATA
ENDIF
;===============================================================;
; Copy initializers into the proper memory segments for decla- ;
; rations like: ;
; ;
; int i = 7; ;
; idata char *cp = "STRING"; ;
;===============================================================;
INIT_VARS:
MOV DPTR,#BDATA_TABLE ; BDATA
IF lcall_mode
LCALL DI_INIT
ELSE
ACALL DI_INIT
ENDIF
MOV DPTR,#DATA_TABLE ; DATA
IF lcall_mode
LCALL DI_INIT
ELSE
ACALL DI_INIT
ENDIF
MOV DPTR,#IDATA_TABLE ; IDATA
IF lcall_mode
LCALL DI_INIT
ELSE
ACALL DI_INIT
ENDIF
MOV DPTR,#PDATA_TABLE ; PDATA
IF lcall_mode
LCALL X_INIT
ENDIF
IF lcall_mode
MOV DPTR,#XDATA_TABLE ; XDATA
LCALL X_INIT
MOV DPTR,#YDATA_TABLE ; For the -y compiler option
LCALL X_INIT
ENDIF
skip_init:
;---------------------------------------------------------------;
; C variable initialization section end ;
;---------------------------------------------------------------;
;---------------------------------------------------------------;
; Activate the (at link-time) selected register bank. ;
;---------------------------------------------------------------;
MOV PSW,#_R
;---------------------------------------------------------------;
; If hardware must be initiated from assembly or if interrupts ;
; should be on when reaching main, this is the place to insert ;
; such code. ;
;---------------------------------------------------------------;
IF banked_mode
MOV A,#$BYTE3 main
MOV DPTR,#LWRD(main)
LCALL ?X_CALL_L18 ; main()
ELSE
IF lcall_mode
LCALL main ; main()
ELSE
ACALL main ; main()
ENDIF
ENDIF
;---------------------------------------------------------------;
; Now when we are ready with our C program (usually 8051 C ;
; programs are continuous) we must perform a system-dependent ;
; action. In this simple case we just stop. ;
;---------------------------------------------------------------;
; DO NOT CHANGE NEXT LINE OF CSTARTUP IF YOU WANT TO RUN YOUR ;
; SOFTWARE WITH THE AID OF THE C-SPY HLL DEBUGGER. IT CAN ;
; THOUGH BE REMOVED IF YOUR PROGRAM IS CONTINUOUS (NO EXIT). ;
; If it is removed the EXTERN ?C_EXIT line should also be re- ;
; moved to avoid linking of the "exit" module ;
;---------------------------------------------------------------;
IF lcall_mode
LJMP exit
ELSE
AJMP exit
ENDIF
;---------------------------------------------------------------;
; Last part of the C variable initializer code. ;
;---------------------------------------------------------------;
IF lcall_mode
COMP_R67_DPTR:
;===========================;
; *** WDG *** ;
; ;
; ACC, B, R0-R3 may be used ;
;===========================;
MOV A,R7
XRL A,DPL
JNZ NOT_EQUAL
MOV A,R6
XRL A,DPH
NOT_EQUAL:
RET
ENDIF
DI_INIT:
CLR A
MOVC A,@A+DPTR
MOV R0,A
MOV A,#1
MOVC A,@A+DPTR
MOV R1,A
MOV A,#2
MOVC A,@A+DPTR
MOV R6,A
MOV A,#3
MOVC A,@A+DPTR
MOV DPL,A
MOV DPH,R6
MORE_DI_COPY:
;===========================;
; *** WDG *** ;
; ;
; ACC, B, R2-R6 may be used ;
;===========================;
MOV A,R0
XRL A,R1
JNZ $+3
RET
CLR A
MOVC A,@A+DPTR
MOV @R0,A
INC DPTR
INC R0
SJMP MORE_DI_COPY
IF lcall_mode
X_INIT:
CLR A
MOVC A,@A+DPTR
MOV R4,A
MOV A,#1
MOVC A,@A+DPTR
MOV R5,A
MOV A,#2
MOVC A,@A+DPTR
MOV R6,A
MOV A,#3
MOVC A,@A+DPTR
MOV R7,A
MOV A,#4
MOVC A,@A+DPTR
MOV R0,A
MOV A,#5
MOVC A,@A+DPTR
MOV DPL,A
MOV DPH,R0
MORE_X_COPY:
LCALL COMP_R67_DPTR
JNZ $+3
RET
CLR A
MOVC A,@A+DPTR
INC DPTR
MOV R0,DPH
MOV R1,DPL
MOV DPH,R4
MOV DPL,R5
MOVX @DPTR,A
INC DPTR
MOV R4,DPH
MOV R5,DPL
MOV DPH,R0
MOV DPL,R1
SJMP MORE_X_COPY
ENDIF
BDATA_TABLE:
DB SFB (B_IDATA)
DB SFE (B_IDATA)
DW SFB (B_CDATA)
DATA_TABLE:
DB SFB (D_IDATA)
DB SFE (D_IDATA)
DW SFB (D_CDATA)
IDATA_TABLE:
DB SFB (I_IDATA)
DB SFE (I_IDATA)
DW SFB (I_CDATA)
PDATA_TABLE:
DW SFB (P_IDATA)
DW SFE (P_CDATA)
DW SFB (P_CDATA)
IF lcall_mode
XDATA_TABLE:
DW SFB (X_IDATA)
DW SFE (X_CDATA)
DW SFB (X_CDATA)
YDATA_TABLE:
DW SFB (ECSTR)
DW SFE (CCSTR)
DW SFB (CCSTR)
ENDIF
ENDMOD startup
;---------------------------------------------------------------;
; Function/module: exit (int code) ;
; ;
; When C-SPY is used this code will automatically be replaced ;
; by a 'debug' version of exit(). ;
;---------------------------------------------------------------;
MODULE exit
PUBLIC exit
$DEFFN exit(0,0,0,0,0,0,0,0)
PUBLIC ?C_EXIT
RSEG RCODE
?C_EXIT:
exit:
;---------------------------------------------------------------;
; The next line could be replaced by user defined code. ;
;---------------------------------------------------------------;
SJMP $ ; Forever...
ENDMOD
;----------------------------------------------------------------------
;
; The only action of this default version of __low_level_init is to
; return 1. By doing so it signals that normal initialization of data
; segments should be done.
;
; A customized version of __low_level_init may be created in order to
; perform initialization before initializing segments and calling main
; and/or to skip initialization of data segments under certain
; circumstances.
; For further details see sample file lowinit.c
;
;----------------------------------------------------------------------
MODULE lowinit
PUBLIC __low_level_init
$DEFFN __low_level_init(0,0,0,0,32768,0,0,0)
RSEG CODE
__low_level_init:
MOV R4,#1 ; By returning 1 this function
; MOV R4,#0 ; 20010801 modified by lobo to zero to skip low level init
MOV R5,#0 ; indicates that the normal
; initialization should take place
IF banked_mode
EXTERN ?X_RET_L18
LJMP ?X_RET_L18
ELSE
RET
ENDIF
END
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