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16-bits multiplication/adition problem?

 
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Derek
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16-bits multiplication/adition problem?
PostPosted: Mon Jan 13, 2003 2:07 pm     Reply with quote

I have a quick question in regards to multiplication. I don't seem to be able to multiply/add anything greater than 8bits.

I have the PCH compiler version 3.086 for a PIC16F877.

Here's the code.

int16 temp_window;

temp_window = 1*256;
printf( "\%4x", temp_window ); //displays 0000
temp_window = temp_window + 0xbc;
printf( "\%4x", temp_window ); //displays 00bc

or

temp_window = temp_window + 0xbc;
printf( "\%4x", temp_window ); //displays 00bc
temp_window = temp_window + 0xbc;
printf( "\%4x", temp_window ); //displays 0078

how come the 16 bit variable is truncating???

please help...
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This message was ported from CCS's old forum
Original Post ID: 10659
PCM programmer



Joined: 06 Sep 2003
Posts: 20137

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Re: 16-bits multiplication/adition problem?
PostPosted: Mon Jan 13, 2003 2:16 pm     Reply with quote

:=I have a quick question in regards to multiplication. I don't seem to be able to multiply/add anything greater than 8bits.
:=
:=I have the PCH compiler version 3.086 for a PIC16F877.

You mean the PCM compiler.

:=
:=temp_window = 1*256;
:=printf( "\%4x", temp_window );

In CCS, you have to use "lx" for a 16-bit or 32-bit number.
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This message was ported from CCS's old forum
Original Post ID: 10660
Derek
Guest







Re: 16-bits multiplication/adition problem?
PostPosted: Mon Jan 13, 2003 3:24 pm     Reply with quote

okay, I tried another test.


int16 temp_window;
temp_window = 0x1234;
printf("\%4x", temp_window);

the result that is printed out is 0034

Why's that??? Please help

:=I have a quick question in regards to multiplication. I don't seem to be able to multiply/add anything greater than 8bits.
:=
:=I have the PCH compiler version 3.086 for a PIC16F877.
:=
:=Here's the code.
:=
:=int16 temp_window;
:=
:=temp_window = 1*256;
:=printf( "\%4x", temp_window ); //displays 0000
:=temp_window = temp_window + 0xbc;
:=printf( "\%4x", temp_window ); //displays 00bc
:=
:=or
:=
:=temp_window = temp_window + 0xbc;
:=printf( "\%4x", temp_window ); //displays 00bc
:=temp_window = temp_window + 0xbc;
:=printf( "\%4x", temp_window ); //displays 0078
:=
:=how come the 16 bit variable is truncating???
:=
:=please help...
___________________________
This message was ported from CCS's old forum
Original Post ID: 10663
Dave Yeatman
Guest







Re: 16-bits multiplication/adition problem?
PostPosted: Mon Jan 13, 2003 3:34 pm     Reply with quote

As PCM said "\%4x" is for 8 bit. Try \%4lx".... You are truncating to the two least significant hex digits and adding two leading zeros since you specify four decimal places.... This is not ANSI standard C.


:=okay, I tried another test.
:=
:=
:=int16 temp_window;
:=temp_window = 0x1234;
:=printf("\%4x", temp_window);
:=
:=the result that is printed out is 0034
:=
:=Why's that??? Please help
:=
:=:=I have a quick question in regards to multiplication. I don't seem to be able to multiply/add anything greater than 8bits.
:=:=
:=:=I have the PCH compiler version 3.086 for a PIC16F877.
:=:=
:=:=Here's the code.
:=:=
:=:=int16 temp_window;
:=:=
:=:=temp_window = 1*256;
:=:=printf( "\%4x", temp_window ); //displays 0000
:=:=temp_window = temp_window + 0xbc;
:=:=printf( "\%4x", temp_window ); //displays 00bc
:=:=
:=:=or
:=:=
:=:=temp_window = temp_window + 0xbc;
:=:=printf( "\%4x", temp_window ); //displays 00bc
:=:=temp_window = temp_window + 0xbc;
:=:=printf( "\%4x", temp_window ); //displays 0078
:=:=
:=:=how come the 16 bit variable is truncating???
:=:=
:=:=please help...
___________________________
This message was ported from CCS's old forum
Original Post ID: 10664
Derek
Guest







Re: 16-bits multiplication/adition problem?
PostPosted: Mon Jan 13, 2003 3:52 pm     Reply with quote

Yes, I mean PCM. I though the L portion of \%Lx is the length I would like to specify; as in the example.

\%4X 0012 00FE

:=:=I have a quick question in regards to multiplication. I don't seem to be able to multiply/add anything greater than 8bits.
:=:=
:=:=I have the PCH compiler version 3.086 for a PIC16F877.
:=
:=You mean the PCM compiler.
:=
:=:=
:=:=temp_window = 1*256;
:=:=printf( "\%4x", temp_window );
:=
:=In CCS, you have to use "lx" for a 16-bit or 32-bit number.
___________________________
This message was ported from CCS's old forum
Original Post ID: 10665
Derek
Guest







Re: 16-bits multiplication/adition problem?
PostPosted: Mon Jan 13, 2003 3:57 pm     Reply with quote

Oh, I got it to work. Thanks guys. All this time, I thought it was some sort of type casting problem and it drove me nuts.

Derek

:=As PCM said "\%4x" is for 8 bit. Try \%4lx".... You are truncating to the two least significant hex digits and adding two leading zeros since you specify four decimal places.... This is not ANSI standard C.
:=
:=
:=:=okay, I tried another test.
:=:=
:=:=
:=:=int16 temp_window;
:=:=temp_window = 0x1234;
:=:=printf("\%4x", temp_window);
:=:=
:=:=the result that is printed out is 0034
:=:=
:=:=Why's that??? Please help
:=:=
:=:=:=I have a quick question in regards to multiplication. I don't seem to be able to multiply/add anything greater than 8bits.
:=:=:=
:=:=:=I have the PCH compiler version 3.086 for a PIC16F877.
:=:=:=
:=:=:=Here's the code.
:=:=:=
:=:=:=int16 temp_window;
:=:=:=
:=:=:=temp_window = 1*256;
:=:=:=printf( "\%4x", temp_window ); //displays 0000
:=:=:=temp_window = temp_window + 0xbc;
:=:=:=printf( "\%4x", temp_window ); //displays 00bc
:=:=:=
:=:=:=or
:=:=:=
:=:=:=temp_window = temp_window + 0xbc;
:=:=:=printf( "\%4x", temp_window ); //displays 00bc
:=:=:=temp_window = temp_window + 0xbc;
:=:=:=printf( "\%4x", temp_window ); //displays 0078
:=:=:=
:=:=:=how come the 16 bit variable is truncating???
:=:=:=
:=:=:=please help...
___________________________
This message was ported from CCS's old forum
Original Post ID: 10666
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