User:Omei Qunhua

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Revision as of 08:21, 31 December 2012 by Omei Qunhua (talk | contribs) (added x+=x; x=-~-~x;)
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Mono Code Size Measurements Results from my own tests in December 2012

1) Accessing a local integer variable

  Results ordered by size
Instruction      ByteCode size
(x);                  2
(~x);                 3
x+x                   4
x=~x;                 5
x=-x;                 5
++x;                  6 
x=x+x;                6     
x=-~x;                6    equates to ++x
x=~-x;                6    equates to --x
x=x^x;                6    equates to x=0
x = !x;               7
if (~x);              7    if (x != -1)
x++;                  8
x=0;                  8
x=9;                  8
x=-~-~x;              8     equates to x+=2
x=-9;                 9     Oh !!   Does it load a +9 then negate it?
x+=1;                 10
x-=x;                 10
x=x=x;                10
x=x*2;                10
x*=2;                 10
if(!~x)               10   if (x == -1)
x *= -1;              11
x<<1;                 12
if(x<0);              13
if(x==-1);            14
x=x<<1;               14

2) Accessing a local integer variable

  Results grouped by functionality
Instruction          Size     Assumed operations
negate x:-
x=-x;                 5     (load x, negate, store)
x*=-1;                11

zeroise x:-
x=0;                  8
x=x-x;               10
x-=x;                10
x=x^x;                6     (load x, xor with x, store)

double x:-
x=x*2;                10
x=x<<1;               14
x=x+x;                6     (load x, add x, store)
x+=x;                 6

increment x by 1
++x;                  6
x++;                  8     (because it has to preserve what it knows about x from before the increment)
x=-~x;                6     (equates to ++x, not x++, so no size advantage)
x+=1;                 10

increment x by 2
x=-~-~x;              8   equates to x+=2
x+=2;                10


List storage Requirements in Mono

These figures differ from those given in http://wiki.secondlife.com/wiki/LSL_Script_Memory

Maybe Mono has been tightened up a bit.

Integer                   16 bytes each
Float                     16 bytes each
String                    18 each plus 2 bytes per character
Key (valid keys)
    (stored as keys)     102 bytes (!!) per key
Key (valid keys)
    (stored as strings)   90 bytes per key
(key) ""                  30 bytes
Vector                    24 bytes each   
Rotation                  28 bytes each