MULLW k - Multiply literal with WREG , ERROR

[yo2lio]

MULLW k - Multiply literal with WREG , ERROR in Software Simulator.

Please run this short program in simulator . MCU P18F452

Code: Select all

program test_MULLW;

var data : word;

begin
  FSR2Ptr := @data;
  WREG := $FF;
  asm
    mullw $FF
  end;
  POSTINC2 := PRODL;
  INDF2 := PRODH;
// data must be $FFFF, but is $00F3
end.

[zristic]

Please run this short program in simulator .

What should happen and what really happens? Please specify. Again, the reprot is incomplete.
Thanks for understanding.

[yo2lio]

data must be $FFFF, but is $00F3

Wreg = 255
After instruction MULLW 255, PRODH and PRODL must be 255 and is not !!

[zristic]

data must be $FFFF, but is $00F3

Wreg = 255
After instruction MULLW 255, PRODH and PRODL must be 255 and is not !!

Thank you, now it is easier to find the problem.

[yo2lio]

I found the BUG

MULLW 10 ASM instruction must generate HEX instruction $0D0A but i found $0008.
MULLW 100 ASM instruction must generate HEX instruction $0D64 but i found $0004.

I can't handle this situation .

[zristic]

We will fix it. Thanks.

[janni]

Could you also fix the problem with retfie? It' always being translated to $0011, whatever the user's intentions:

Code: Select all

             is    should be

retfie     $0011   $0010  (default)
retfie 0   $0011   $0010
retfie 1   $0011   $0011

[zristic]

Could you also fix the problem with retfie?

Yep, of course.

[janni]

Another one - CALL xx,FAST doesn't work (as well as RETURN FAST). Call is always coded as $EC.. while it should be $ED... for CALL xx,FAST.

That's quite dangerous as the only workaround for some PIC18s problem with storing/restoring registers on interrupt with RETFIE,FAST (default in mP) involves CALL xx,FAST.

Unfortunatelly, I've sold many controllers based on PIC18F4620 where this problem shows up. I wonder how much the compiler error will cost me this time...

[zristic]

See here:
http://www.mikroe.com/forum/viewtopic.php?p=61596#61596

Fixed for v.7.01

[janni]

The trick doesn't work with CALL

[zristic]

The trick doesn't work with CAL

Fixed for CALL too.
Finally...

[zristic]

MULLW 10 ASM instruction must generate HEX instruction $0D0A but i found $0008.
MULLW 100 ASM instruction must generate HEX instruction $0D64 but i found $0004.

Fixed.

[zristic]

Code: Select all

program test_MULLW;

var data : word;

begin
  FSR2Ptr := @data;
  WREG := $FF;
  asm
    mullw $FF
  end;
  POSTINC2 := PRODL;
  INDF2 := PRODH;
// data must be $FFFF, but is $00F3
end.

The correct result is not $FFFF, neither it is $00F3 but it is $FE01.

[yo2lio]

Code: Select all

program test_MULLW;

var data : word;

begin
  FSR2Ptr := @data;
  WREG := $FF;
  asm
    mullw $FF
  end;
  POSTINC2 := PRODL;
  INDF2 := PRODH;
// data must be $FFFF, but is $00F3
end.

The correct result is not $FFFF, neither it is $00F3 but it is $FE01.

Yes, thanks !

I think, the new compiler is very nearly !