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Locating 2 parameters at the same address

Jeff Tonkinson

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
  • 0 in reply to Andy Neil

    "Just because you've managed to avoid the problems does not mean that there are no problems."

    Andy, what problems are you talking about? I certainly didn't have to avoid any problems. There weren't any problems in what I did. Why? because I understood how the 51 works, how the assembler works, what the compiler produced, how the linker works, and what I wanted to achieve. There were no problems and no gotchas.

    "Just like crossing the road has many dangers ..."

    That's an extremely poor example. Processors are (in general) highly predictable. Crossing the road is totally different. You are not in control of all the variables - Most importantly there is that unknown variable sitting behind the wheel of a large mass.

    "But saying there are NO dangers is untrue and unhelpful."

    That seems to lack a certain amount of context. Go back and you'll see my post ended with:

    No problem, so long as you know what you're doing, period.

    So ... going back to the full post and full context, what I was saying is that there is no danger in doing it per se. You (and others) might consider it a danger in the context of Keil's implementation of C - But in itself I stand by what I said.

Reply
  • 0 in reply to Andy Neil

    "Just because you've managed to avoid the problems does not mean that there are no problems."

    Andy, what problems are you talking about? I certainly didn't have to avoid any problems. There weren't any problems in what I did. Why? because I understood how the 51 works, how the assembler works, what the compiler produced, how the linker works, and what I wanted to achieve. There were no problems and no gotchas.

    "Just like crossing the road has many dangers ..."

    That's an extremely poor example. Processors are (in general) highly predictable. Crossing the road is totally different. You are not in control of all the variables - Most importantly there is that unknown variable sitting behind the wheel of a large mass.

    "But saying there are NO dangers is untrue and unhelpful."

    That seems to lack a certain amount of context. Go back and you'll see my post ended with:

    No problem, so long as you know what you're doing, period.

    So ... going back to the full post and full context, what I was saying is that there is no danger in doing it per se. You (and others) might consider it a danger in the context of Keil's implementation of C - But in itself I stand by what I said.

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