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tthsqe



Joined: 20 May 2009
Posts: 729
tthsqe
I know the irp macro can be used to loop over a given set of values, but it is possible to do something like this:
Code:
rept 10 i:0 {
 mov eax,[[table+4*i^2]]
}
table: dd 0,1,2,3,4,5,6,7,8,...    

and have the code generated be:
Code:
 mov eax,0
 mov eax,1
 mov eax,4
 mov eax,9
...    

Essentialy fasm need to find the value from the address and substitue it in instead of encoding it as a memory access.
Post 30 Oct 2009, 07:49
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17287
Location: In your JS exploiting you and your system
revolution
Read up about the load directive.
Code:
table: dd 0,1,2,whatever,...
rept 10 i:0 {
  load x dword from table+4*i*i
  mov eax,x
}    
Post 30 Oct 2009, 08:09
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17287
Location: In your JS exploiting you and your system
revolution
But if all you want to do is generate squares then:
Code:
rept 10 i:0 {
  mov eax,i*i
}    
Post 30 Oct 2009, 08:12
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tthsqe



Joined: 20 May 2009
Posts: 729
tthsqe
How about this one:
How can you get fasm to compile something like this:
Code:
.ifc
x1
.nz
y1
.elseif
x2
.nz
y2
.elseif
x3
.nz
y3
.else
y4
.endif    

into:
Code:
x1
jnz .1
x2
jnz .2
x3
jnz .3
y4
jmp .end
.3:
y3
jmp .end
.2:
y2
jmp .end
.1:
y1
.end:    


It essentially involves movinf the intruction blocks y1,y2,.. around but keeping the condition checking block x1,x2 in the same order.
Post 19 Nov 2009, 06:24
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