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PSoC 5, 3 & 1 MCU

HuEl_264296
New Contributor II

Hi all,

   

Just looking at the assembler output from PSoC Creator for the PSoC 3. The code:

   

 

   

uint8 *p=0;
p++;

   

 

   

produces this assembler:

   

 

   

MOV     DPTR,#p+01H
CLR     A
MOV     B,#01H
LCALL   ?C?IILDX
 

   

A call? To increment a pointer? What's with that?

   

 

   

Hugo

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3 Replies
TeHe_281121
New Contributor

Looking at the Map file, shows the function residing in the C51L lib file.

   

....\PSOC CREATOR\IMPORT\KEIL\PK51\8.16\C51\LIB\C51L.LIB (?C?IILDX)
 

   

Using the library manager to create a list of the public functions of C51L.lib, verifies this.

   

?C?IILDX
      ?C?IILDX
 

   

..and looking at the MAP file again, shows it may be some 21 bytes long:

   

0100009AH   CODE     ---       ?C?IILDX
010000B0H   CODE     ---       ?C?ISTPTR
 

   

My guess it could be some bank switching or address checking code.

   

You may want to direct this question directly to KEIL.

   

PS: the \LIB folder contains code for the Lib files, but I can't seem to match the function in question.

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HuEl_264296
New Contributor II

I don't understand why people aren't more surprised and concerned about this? Incrementing a value is one of the most fundamental operations in any code.

   

 

   

Even MPLAB's basic C compiler for the PIC18  generates the expected instructions for an increment.

   

 

   

Are there any better compilers available for the PSoC ?

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RoNo_264271
Contributor II

Are you sure the pointer increment isn't optimized out and the lcall belongs to this increment?

   

Regards,

   

Rolf

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