db ((val1 shl 4) and val2)

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rambo

Joined: 28 Feb 2005
Posts: 22
Location: posen, poland

rambo 16 Aug 2005, 13:21

i`d like to have a macro, which performs operation:

Code:

(byteval1 << 4) & byteval2

and then writes result as a byte.
so i wrote:

Code:

macro wval val1, val2 { db ((val1 shl 4) and val2) }

but it doesn`t work (writes zeeero).
where is my fault?

16 Aug 2005, 13:21

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8351
Location: Kraków, Poland

Tomasz Grysztar 16 Aug 2005, 13:30

Seems to be converted correctly. With what values do you use it, and what result do you expect?

16 Aug 2005, 13:30

rambo

Joined: 28 Feb 2005
Posts: 22
Location: posen, poland

rambo 16 Aug 2005, 13:35

values are of course bytes from 0 to 15, and i expect first byte in byte`s hi nibble and second byte in lo nibble.

little example of using it by me:

Code:

something equ 0x09
..
wval something, 1

and i`m using it inside others macros..

16 Aug 2005, 13:35

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8351
Location: Kraków, Poland

Tomasz Grysztar 16 Aug 2005, 13:36

Oh, so you mean |, not &. In fasm it should be:

Code:

db val1 shl 4 or val2

(SHL has higher priority than OR/AND, but you can use parenthesis if you feel more comfortable this way).

16 Aug 2005, 13:36

rambo

Joined: 28 Feb 2005
Posts: 22
Location: posen, poland

rambo 16 Aug 2005, 13:40

oh, yeah : )
i`m ashamed : ))
thanks.

16 Aug 2005, 13:40

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