logp (Vertex Shader)
Partial precision log2(x).
Syntax
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 versions | 1_1 | 2_0 | 2_x | 2_sw | 3_0 | 3_sw |
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| logp | x | x | x | x | x | x |
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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.
Instruction Information
| Minimum operating system | Windows 98 |
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