Freescale 8位单片机例程

/****************************************************************************** FILE : start08.c PURPOSE : 68HC08 standard startup code LANGUAGE : ANSI-C / INLINE ASSEMBLER ---------------------------------------------------------------------------- HISTORY 22 oct 93 Created. 04/17/97 Also C++ constructors called in Init(). ******************************************************************************/ /**********************************************************************/ /* NOTE: */ /* This version of the startup code assumes that main */ /* does never return (saving the 2 byte return address of _Startup on */ /* the stack). */ /**********************************************************************/ #define __NO_FLAGS_OFFSET /* we do not need the flags field in the startup data descriptor */ #define __NO_MAIN_OFFSET /* we do not need the main field in the startup data descriptor */ #include <start08.h> #ifdef __cplusplus #define __EXTERN_C extern "C" #else #define __EXTERN_C #endif __EXTERN_C extern void main(void); /* prototype of main function */ #include "non_bank.sgm" /***************************************************************************/ /* Macros to control how the startup code handles the COP: */ /* #define _DO_FEED_COP_ : do feed the COP */ /* Without defining any of these, the startup code does NOT handle the COP */ /***************************************************************************/ /* __ONLY_INIT_SP define: */ /* This define selects an shorter version of the startup code */ /* which only loads the stack pointer and directly afterwards calls */ /* main. This version does however NOT initialize global variables */ /* (so this version is not ANSI compliant!). */ /***************************************************************************/ #if defined(_DO_FEED_COP_) #define __FEED_COP_IN_HLI() } _FEED_COP(); __asm { #else #define __FEED_COP_IN_HLI() /* do nothing */ #endif #ifndef __ONLY_INIT_SP #pragma DATA_SEG FAR _STARTUP struct _tagStartup _startupData; /* read-only: _startupData is allocated in ROM and initialized by the linker */ #pragma MESSAGE DISABLE C20001 /* Warning C20001: Different value of stackpointer depending on control-flow */ /* the function _COPY_L releases some bytes from the stack internally */ #if defined(__OPTIMIZE_FOR_SIZE__) || defined(_DO_FEED_COP_) #pragma NO_ENTRY #pragma NO_EXIT #pragma NO_FRAME /*lint -esym(528, loadByte) inhibit warning about unreferenced loadByte function */ static void near loadByte(void) { asm { PSHH PSHX #ifdef __HCS08__ LDHX 5,SP LDA 0,X AIX #1 STHX 5,SP #else LDA 5,SP PSHA LDX 7,SP PULH LDA 0,X AIX #1 STX 6,SP PSHH PULX STX 5,SP #endif PULX PULH RTS } } #endif /* defined(__OPTIMIZE_FOR_SIZE__) || defined(_DO_FEED_COP_) */ #ifdef __cplusplus static void Call_Constructors(void) { int i; #ifdef __ELF_OBJECT_FILE_FORMAT__ i = (int)(_startupData.nofInitBodies - 1); while (i >= 0) { (&_startupData.initBodies->initFunc)[i](); /* call C++ constructors */ i--; } #else /* __ELF_OBJECT_FILE_FORMAT__ */ /* HIWARE object file format */ if (_startupData.mInits != NULL) { _PFunc *fktPtr; fktPtr = _startupData.mInits; while(*fktPtr != NULL) { (**fktPtr)(); /* call constructor */ fktPtr++; } } #endif /* __ELF_OBJECT_FILE_FORMAT__ */ } #endif /*lint -esym(752,_COPY_L) inhibit message on function declared, but not used (it is used in HLI) */ __EXTERN_C extern void _COPY_L(void); /* DESC: copy very large structures (>= 256 bytes) in 16-bit address space (stack incl.) IN: TOS count, TOS(2) @dest, H:X @src OUT: WRITTEN: X,H */ #ifdef __ELF_OBJECT_FILE_FORMAT__ #define toCopyDownBegOffs 0 #else #define toCopyDownBegOffs 2 /* for the hiware format, the toCopyDownBeg field is a long. Because the HC08 is big endian, we have to use an offset of 2 */ #endif static void Init(void) { /* purpose: 1) zero out RAM-areas where data is allocated 2) init run-time data 3) copy initialization data from ROM to RAM */ /*lint -esym(529,p,i) inhibit warning about symbols not used: it is used in HLI below */ int i; int *far p; asm { ZeroOut: LDA _startupData.nofZeroOuts:1 ; // nofZeroOuts INCA STA i:1 ; // i is counter for number of zero outs LDA _startupData.nofZeroOuts:0 ; // nofZeroOuts INCA STA i:0 LDHX _startupData.pZeroOut ; // *pZeroOut BRA Zero_5 Zero_3: ; // CLR i:1 is already 0 Zero_4: ; // { HX == _pZeroOut } PSHX PSHH ; // { nof bytes in (int)2,X } ; // { address in (int)0,X } LDA 0,X PSHA LDA 2,X INCA STA p ; // p:0 is used for high byte of byte counter LDA 3,X LDX 1,X PULH INCA BRA Zero_0 Zero_1: ; // CLRA A is already 0, so we do not have to clear it Zero_2: CLR 0,X AIX #1 __FEED_COP_IN_HLI() ; // it's necessary to feed the COP in the inner loop for the fast COP timeout of some derivatives Zero_0: DBNZA Zero_2 Zero_6: DBNZ p, Zero_1 PULH PULX ; // restore *pZeroOut AIX #4 ; // advance *pZeroOut Zero_5: DBNZ i:1, Zero_4 DBNZ i:0, Zero_3 CopyDown: } /* copy down */ /* _startupData.toCopyDownBeg ---> {nof(16) dstAddr(16) {bytes(8)}^nof} Zero(16) */ #if defined(__OPTIMIZE_FOR_SIZE__) || defined(_DO_FEED_COP_) /* for now: only -os version supports _DO_FEED_COP_ */ asm { #ifdef __HCS08__ LDHX _startupData.toCopyDownBeg:toCopyDownBegOffs PSHX PSHH #else LDA _startupData.toCopyDownBeg:(1+toCopyDownBegOffs) PSHA LDA _startupData.toCopyDownBeg:(0+toCopyDownBegOffs) PSHA #endif Loop0: JSR loadByte ; // load high byte counter TAX ; // save for compare INCA STA i JSR loadByte ; // load low byte counter INCA STA i:1 DECA BNE notfinished CBEQX #0, finished notfinished: JSR loadByte ; // load high byte ptr PSHA PULH JSR loadByte ; // load low byte ptr TAX ; // HX is now destination pointer BRA Loop1 Loop3: Loop2: __FEED_COP_IN_HLI() JSR loadByte ; // load data byte STA 0,X AIX #1 Loop1: DBNZ i:1, Loop2 DBNZ i:0, Loop3 BRA Loop0 finished: