logp - vs

Partial precision logp2(x).

Syntax

logp dst, src

 

where

  • dst is the destination register.
  • src is a source register. Source register requires explicit use of replicate swizzle, that is, exactly one of the .x, .y, .z, .w swizzle components (or the .r, .g, .b, .a equivalents) must be specified.

Remarks

Vertex shader versions1_12_02_x2_sw3_03_sw
logpxxxxxx

 

The following code fragment shows the operations performed.



float f = abs(src);
if (f != 0)
    dest.x = dest.y = dest.z = dest.w = (float)(log(f)/log(2));
else
    dest.x = dest.y = dest.z = dest.w = -FLT_MAX;   


This instruction provides logarithm base 2 partial precision, up to 10 bits.

 

 

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