gnupic: gpasm bugs
Subject:
Re: gpasm bugs
From:
####@####.#### (Byron A Jeff)
Date:
25 Mar 2002 21:32:13 -0000
Message-Id: <200203252125.g2PLPc928290@cleon.cc.gatech.edu>
>
> With / to whom should I consult about bugs in gpasm ? There are no bugs
> listed in sourceforge.net (or maybe I'm not using it right).
>
> invalid instructions like:
> movf RamLocation1, RamLocation2
>
> are accepted but clearly not legal. (I'm a beginner and I forgot that
> you can't do this, you have to go thru w) (on the 16f877 at least)
For all pics.
However your assumption is incorrect. It's a perfectly legal instruction.
However it won't perform the behavior intended.
The assembler treats the second operand of the instruction as a number. So
as far as it's concerned whatever value RamLocation2 represents is the number
for the second operand. Also that operand is a single bit, so the assember
only uses the least significant bit. Here's a real brief sample.
0000 0805 00035 movf PORTA,W
0001 0885 00036 movf PORTA,F
0002 0B05 00037 movf PORTA,PORTB
0003 0A85 00038 movf PORTA,PORTA
Note the two correct instructions at the top. The latter two only use the
LSB of PORTB (6) and PORTA (5), thereby generating the same instructions
as the top two for W (0) and F (1).
>
> there are also documentation clarifications that would be helpful... I
> have a few suggestions coming from a newbie to PIC and linux in general.
Well let's hear them. I'm sure that Scott and Craig would be thrilled to have
someone help on documentation.
BAJ
>
> Thanks ...
> Jesse
>
>
> --
> Bill Gates is a crook and millions of tax dollars have been spent
> prosecuting and convicting Microsoft of illegal business practices. Do
> not give them another dime until they have repaid the US government
> these costs.
>
>
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