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pool

Joined: 08 Jan 2007
Posts: 97
Location: Philippines

pool

Last edited by pool on 17 Mar 2013, 11:44; edited 1 time in total

12 Mar 2008, 11:41

edfed

Joined: 20 Feb 2006
Posts: 4237
Location: 2018

edfed

first, it is not shl 2 and shr 2 but shl 1 and shr 1. due to the binary numeral system. shl and shr on base 10 numbers will divide and mul by power of 10

second, for square root, log, cos, sin, there is no easy binary way similara to shr ans shl

third, it is not the place to speak about. here, it is os construction, and this speak about a main or heap subject.

12 Mar 2008, 11:49

bitRAKE

Joined: 21 Jul 2003
Posts: 2891
Location: [RSP+8*5]

bitRAKE

square root is more complicated:

Code:

Sqrt:   xor ecx,ecx
        xor eax,eax
        bsr edx,[esp+4]
        je .x
        and edx,-2      ; even
        bts ecx,edx

.0:     add eax,ecx
        sub [esp+4],eax
        jnc .1
        add [esp+4],eax
        sub eax,ecx
        jmp .2

.1:     add eax,ecx
.2:     shr eax,1
        shr ecx,2
        jne .0
.x:     retn 4
; EAX = square root

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12 Mar 2008, 12:20

pool

Joined: 08 Jan 2007
Posts: 97
Location: Philippines

pool

Last edited by pool on 17 Mar 2013, 11:44; edited 1 time in total

24 Mar 2008, 03:59

edfed

Joined: 20 Feb 2006
Posts: 4237
Location: 2018

edfed

for that, don't try square root.
the square is enough to know the distance.

and in 3D, the principle is to simplify the equation, then, the algo will be little.

x2D = k (x/z)
y2D = k (y/z)

24 Mar 2008, 11:37

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