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Locating 2 parameters at the same address

I am using an 8051 (C51/BL51) with no off-chip memory. I have two functions with parameters:

void Detect( U8 iLed )

and

static U8 INHSampleHandler( U16 u16Sample )


Now I understand that Keil will allocate a variable (in DATA) for these. The problem seems to be that the locator is using the same memory location for both. I cannot understand why.

Below are excerpts from the scratchpad showing 2 "D:0026H". These are the only places these symbols are declared. Any ideas what I'm doing wrong?

Thanks,
Jeff

BL51 BANKED LINKER/LOCATER V5.12              07/14/2011  09:36:23  PAGE 1


BL51 BANKED LINKER/LOCATER V5.12, INVOKED BY:
Z:\TOOLS\SOFTWARE\KEIL\BL51.EXE Z:\Software\FB_CPU_Init.obj,
>> Z:\Software\Settings.obj, Z:\Software\Glo
>> bals.obj, Z:\Software\Devices\Clock.obj, Z:\ 
>> Software\Devices\Flash.obj, Z:\Software\Devices\HMI.obj
>> , Z:\Software\Devices\INH.obj, Z:\ 
>> Software\Devices\ADC.obj, Z:\Software\Devices\Timer.obj, Z
>> :\Software\Builds\TestINH - 06-00039-21-09\Main.obj
>> , Z:\Software\Test\Test_Button.obj, Z:\So
>> ftware\Builds\TestINH - 06-00039-21-09\Version.obj TO Z:\ 
>> Software\Builds\TestINH - 06-00039-21-09\06-00039-21-09-xx.wsp
>>  RS (256) PL (68) PW (78) XDATA (?XD?SETTINGS (0X0)) CODE (?CO?VERSION (0X7
>> FC0))


MEMORY MODEL: SMALL

Deleted for brevity

  -------         PROC          _INHSAMPLEHANDLER
  D:0026H         SYMBOL        u16Sample
  C:0BF1H         LINE#         150
  C:0BF5H         LINE#         151
  C:0BF5H         LINE#         207
  C:0BF7H         LINE#         208
  -------         ENDPROC       _INHSAMPLEHANDLER
  -------         ENDMOD        INH

Deleted for brevity

  C:09FEH         PUBLIC        _Detect
  C:074EH         PUBLIC        main
  -------         PROC          _DETECT
  D:0026H         SYMBOL        iLed

Parents
  • I don't really follow all the discussion above regarding ISRs. Does the linker make sure that ISRs (and their associated call trees) never overlay anything else? It seems like it would have to.

    it does, except when it runs into it's trouble with function pointers.

    There is nothing inherintly wrong with using function pointers with C51 (or any code for the '51) but the mechanisms required makes it bug prone and less maintainable. Thus I (and many others) have a '51 specific coding style that avoids function pointers.

    Erik

Reply
  • I don't really follow all the discussion above regarding ISRs. Does the linker make sure that ISRs (and their associated call trees) never overlay anything else? It seems like it would have to.

    it does, except when it runs into it's trouble with function pointers.

    There is nothing inherintly wrong with using function pointers with C51 (or any code for the '51) but the mechanisms required makes it bug prone and less maintainable. Thus I (and many others) have a '51 specific coding style that avoids function pointers.

    Erik

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