Dabbling with myDVDEdit, got questions

[DeadLily]

Gotta love the control this program gives over re-configuring your backups. My first desire is to get past all the FBI/studio logo/trailer preamble, and get right to the main menu. My first experiment with a relatively simple Warner/BBC DVD seems to have worked. Now I'm tackling Attack of the Clones, which I correctly presumed would be a bigger challenge.

The trick seems to be tracking the values assigned to various registers (R0, R15, etc.) before arriving to the main menu, and keeping those consistent so that later options see what they expect to see. This is then fixed by assigning all those values at the First Play section while skipping all commands to display the logo titles. So far so good.

Now I'm confronted by logical operators that I'm not familiar with. These include (but are not limited to) things like:

&=
!=
*=

Eg.:

R0 = 0
R0 &= 255

In this example, what does "&=" do? And is there somewhere that explains what the other symbols mean? Thanks.

[myDVDEdit]

Hi DeadLily

it's the AND EQUAL STORE operation
R0 &= 255 are same as R0 = R0 & 255
AND are the boolean operation. In this case AND 255 erase the hi byte of your register
eg.:
0x1234 & 255 -> 0x0034 (0x are the hexadecimal number form)

same,
R0 *= 10 are same as R0 = R0 * 10

!= means NOT EQUAL
it's not a STORE operation but a COMPARE

if(R0 != 10) means, IF R0 NOT EQUAL 10 THEN

Regards
Jerome