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Hi Daniel, You are right, the SDD functions are RTS terminated, using near pointers and the JSR instruction solved the problem, thanks a lot! ----- Original Message ----- From: "Daniel Friederich" <> To: <> Sent: Friday, June 13, 2003 1:43 PM Subject: RE: [68HC12] CodeWarrior type cast objptr->funcptr > > Hi Karsten, > > The compiler does not automatically adapt the layout of a function pointer to the different layout of a data pointer. > I don't know you code, but are you sure your routines in NVMInit_C > do expect the far calling convention? Are they RTC terminated or are they using a RTS? > I could imagine that they were written in the small memory model so they end with a RTS > and calling them with a CALL will not work, but I'm not sure. > > If they end with a RTS, then call them with a near function pointer and it should work. > typedef SGF_RESULT (* __near pNVMINIT) ( UINT16 oscClock, > BOOL BDMEnable, > UINT16 regBase, > UINT16 pDescriptor, > UINT16 funcPtr); > > If not, you have to manually convert the data pointer to a function pointer (a rotate) before calling it. > > Bye > > Daniel > > > -----Original Message----- > > From: Karsten Obenaus [mailto:] > > Sent: Friday, June 13, 2003 12:35 > > To: > > Subject: [68HC12] CodeWarrior type cast objptr->funcptr > > > > > > We're using the Metrowerks Codewarrior for HC12 IDE and have encountered a > > problem with the compiler and type casting from an object pointer to a function pointer. > > Any help would be greatly appreciated. > > > > We'd like to use the HCS12 SGF NVM Standard Software Driver in our current > > project (flash/eeprom routines). The SSD consists of various modules that > > contain the function code as hex byte tables. Here's an excerpt from the > > sample code that comes with the SSD: > > > > NVMINIT MODULE: > > const unsigned char NVMInit_C[] = { 0x.., 0x.., ..... }; > > > > SAMPLE CODE: > > typedef SGF_RESULT (*pNVMINIT) ( UINT16 oscClock, > > BOOL BDMEnable, > > UINT16 regBase, > > UINT16 pDescriptor, > > UINT16 funcPtr); > > extern const unsigned char NVMInit_C[]; > > pNVMINIT NVMInit = (pNVMINIT) NVMInit_C; > > > > returnCode = NVMInit(OSC_CLOCK, BDMEnable, REGISTER_BASE_ADDRESS, > > (UINT16)Descriptor, (UINT16)SIMPLE_RANGE_CHECKING); > > > > > > Basically, the pNVMINIT NVMInit = (pNVMINIT) NVMInit_C; instruction performs > > a typecast from an object pointer (NVMInit_C) to a function pointer > > (NVMInit). This causes a C1805 compiler warning. > > > > Let's take a look at the generated code: > > > > LEAS -3,SP > > LDD #NVMInit_C > > STD 1,SP > > CLRB > > STAB 0,SP > > . > > now the function parameters are being pushed onto the stack (7 bytes) > > . > > CALL [0x0007,SP] > > > > As you can see the compiler pushes the address 0x00hhll onto the stack, hh > > being high byte of the NVMInit_C address, ll being the low byte, 0x00 being > > the page. However, the CALL instruction expects the subroutine address in > > the format hhllpp (pp being 0x00 in this case). This means the value > > 0x00hhll turns into a subroutine address 00hh in page ll. > > > > In order for the CALL instruction to work properly the compiler should > > generate this code instead: > > LEAS -3,SP > > CLRB > > STAB 2,SP > > LDD #NVMInit_C > > STD 0,SP > > > > Is this a compiler error? > > > > > > Karsten Obenaus, > > ModernDrive Technology GmbH > > Am Steinacher Kreuz 24 > > 90427 Nuernberg, Germany > > www.moderndrive.de > > > > > > > > > > > > > > > > -------------------- > > > > > > > > ">http://docs.yahoo.com/info/terms/ > > > > -------------------- > > ">http://docs.yahoo.com/info/terms/ > |