Verifying A Pointer

[Igglyboo]

Would anyone know how to verify a pointer in ASM?
It basically has to do DE000000 80008180does, but in ASM.

[Romaap]

I'm not sure but I think you could use something like this:
cmpwi  rA, 8000
blt  branch to end
cmpwi  rA, 8180
bge  branch to end

[spunit262]

I'm not sure but I think you could use something like this:
cmpwi  rA, 8000
blt  branch to end
cmpwi  rA, 8180
bge  branch to end

That wouldn't work, you'd need a cmpwis which doesn't exist.

Code Select Expand

lis rB,0x8000
cmpw rA,rB
blt- end
lis rB,0x8180
cmpw rA,rB
bge- end

[brkirch]

Code Select Expand

lis rB,0x8000
cmpw rA,rB
blt- end
lis rB,0x8180
cmpw rA,rB
bge- end

Your code is correct but the first three lines are unnecessary.  The comparison for cmpw is signed, and it is impossible for a 32-bit signed integer to be less than 0x80000000 (-2147483648).

[spunit262]

Code Select Expand

lis rB,0x8000
cmpw rA,rB
blt- end
lis rB,0x8180
cmpw rA,rB
bge- end

Your code is correct but the first two lines are unnecessary.  The comparison for cmpw is signed, and it is impossible for a 32-bit signed integer to be less than 0x80000000 (-2147483648).

Forgot about that, and it 3 not 2.
And because I'm bored I'll post one that lets 90 pointer though.

Code Select Expand


lis rB,0x8180
cmpw rA,rB
blt+ 0x1C
lis rB,0x9000
cmpw rA,rB
blt- end
lis rB,0x9380
cmpw rA,rB
bge- end


[brkirch]

Forgot about that, and it 3 not 2.

Yeah that's what I meant, I have no idea why I said two.  :confused:

And because I'm bored I'll post one that lets 90 pointer though.

Code Select Expand


lis rB,0x8180
cmpw rA,rB
blt+ 0x1C
lis rB,0x9000
cmpw rA,rB
blt- end
lis rB,0x9380
cmpw rA,rB
bge- end


And since I'm also bored I'll shorten that slightly :P

Code Select Expand

lis rB,0x8180
cmpw rA,rB
blt+ 0x18
rlwinm rB,rA,16,16,31
cmplwi rB,0x9000
blt- end
cmplwi rB,0x9380
bge- end

[Romaap]

thanks for fixing my mistake