Assembler Language

mleanz1 · 12 Mar 2009 at 11:43

Does anyone know or to work at whether a register value in assembler is odd or even?

Blackvault · 12 Mar 2009 at 11:46

Surely it will be hex, so you'll need to convert it to two's compliment binary. So the MSB (most signifcant bit) will be 1 for neg and 0 for postive.

Blackvault

BullBoyShoes · 12 Mar 2009 at 12:13

asembley language for what system>?

I would divide it by 2 and see if there is a remainder

Shadez · 12 Mar 2009 at 13:44

BullBoyShoes said:
asembley language for what system>?

I would divide it by 2 and see if there is a remainder

no such thing as divide in most assembler languages, well not the ones i use

daz · 12 Mar 2009 at 13:51

Convert to binary and then see if the last bit is 1 or 0 ?

Shadez · 12 Mar 2009 at 14:01

daz said:
Convert to binary and then see if the last bit is 1 or 0 ?

yep its that simple, the LSB is always 1 when its odd and 0 when its even

1 = 0001
2 = 0010
3 = 0011
4 = 0100
5 = 0101
6 = 0110
7 = 0111
8 = 1000
9 = 1001
A = 1010
B = 1011
C = 1100
D = 1101
E = 1110
F = 1111

Code:

Its been awhile but its probably something like this


MOVF SOMEREGISTER,W
BTFSS W,0
GOTO EVEN
//add odd code here
GOTO END
EVEN:
//add even code here
END:

BullBoyShoes · 12 Mar 2009 at 15:09

Shadez said:
no such thing as divide in most assembler languages, well not the ones i use

( x >> 1) == (x / 2)

but yes the above is a lot simpler!

mleanz1 · 12 Mar 2009 at 16:16

Cheers guys LSB is the answer