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Appendix: Technical Details for Designers

Also available in its original form, APPENDIX.TXT, as part of the compressed text file called FS5FCT20.ZIP. Information is available on downloading the original zipped text files. Presented here in enhanced form with the permission of the author, Konstantin Kukushkin, who reserves all rights.

Contents

Instruction timings

Instruction            Execution speed, instructions/second

RefPoint(7)/v2=0 visible        123073
RefPoint(7)/v2!=0 visible        82932
RefPoint(7)/v2=0 invisible      215176
RefPoint(7)/v2!=0 invisible     120705
RefPoint(7)/far away invisible  118613
Call/Return                    1289807

(All ...Call()s were measured together with the corresponding Return.)

RotatedCall( 0 0 0 )            107129
RotatedCall( X 0 0 )             57796
RotatedCall( X X 0 )             39165
RotatedCall( X X X )             29421

(Tests showed that zero displacements in TransformCall() do not increase performance.)

TransformCall( dx dz dy 0 0 0 ) 198047
TransformCall( dx dz dy x 0 0 )  53658
TransformCall( dx dz dy x x 0 )  37201
TransformCall( dx dz dy x x x )  27580

(The following PerspectiveCalls were measured together with Perspective()/Return(). /50 means there were 49 other PerspectiveCall()ed objects. x2 means each object was PerspectiveCall()ed twice.)

PerspectiveCall()/50            101896
PerspectiveCall()/50x2           75600
PerspectiveCall()/100            90810
PerspectiveCall()/100x2          69674
PerspectiveCall()/150            81060
PerspectiveCall()/150x2          62565
PerspectiveCall()/200            78664
PerspectiveCall()/200x2          58152
PerspectiveCall()/250            74930
PerspectiveCall()/250x2          53260

Jump()                         2832031
IfVarAnd()/nojump              1532625
IfVarRange()/jump              1691036
LineColor()                    2954537
SurfaceColor()                 2732680
ShadedColor()                   628461
RepeatBitmap()                 1274459
TexPolyShading()                537598
Bitmap()/enough RAM              82929
Palette()/old                   419843
Palette()/new                      100

(All dots were visible.)

Dot()                            87399
DotPt()                         142809
DotLine()/per dot [5 dots/line]  115360
DotLine()/per dot [10 dots/line] 131400
DotLine()/per dot [25 dots/line] 144000
MoveToPt()/DrawToPt()              5556
MoveTo()/DrawTo()                  5456

(All polygon drawing commands were used to draw a polygon of the same shape at the same location. The drawing time of a solid polygon was the same for palettes 68, 69, and F0.)

Poly()/non-textured              460.29
ShadedPoly()                     127.71
ShadedPoly()/033E=1               87.84?

(All texture mapping commands were used with the same scaling and position of the texture.)

TexWindow()                       59.90
TexWindow()/zoom=4                27.62
TexWindow()/smoothing             52.48
TexWindow()/smoothing zoom=4      24.01
TexPoly()                         31.60
TexPoly()/zoom=4                  31.01
TexPoly()/smoothing               29.59
TexPoly()/smoothing zoom=4        26.14
ShadedTexPoly()                   25.72
ShadedTexPoly()/zoom=4            23.00
ShadedTexPoly()/smoothing         25.40
ShadedTexPoly()/smoothing zoom=4  23.00

Crash codes

(All codes are ignored when crash detection is disabled. Codes not listed may cause crashes as well.)

Code(dec) Message  When       Comments

  1        Crash    Cockpit
 2        Mountain Cockpit
 3        Crash    Cockpit
 4        Crash    Always     Forces zero altitude
 5        Crash    Cockpit
 6        Building Cockpit
 7        Crash    Cockpit
 8        Splash   Cockpit
 9        Crash    Cockpit
10        Gear up  Cockpit
12        Overstress Cockpit
13        Crash    Cockpit
14        Building Always
16        Collision Always    Requires Crash when Hit Objects enabled
18        Fuel truck Always   Requires Crash when Hit Objects enabled
19        Crash     Always
20        Object    Always    Requires Crash when Hit Objects enabled
22        Crash     Cockpit

Different names in FSASM and SCASM

    SCASM         FSASM

Area           Group?R
EndA           EndGroup
Area16         SurfaceGroup
End16          EndSurfaceGroup
RefPoint( 2 ... ) RefPtAMSL
RefPoint( 7 ... ) RefPtGL
Points         DefPoints/Point
VecPoints      DefVecPoints/VecPoint
Brightness     Intensity
BigDot         DotLarge
DrawTo         LineTo
Poly           FlatPoly
RunwayData     Rwy
RunwayLights   RwyLights
RoadMoveTo     RoadWidth/StartRoad
RoadLineTo     DrawRoad
RoadMoveTo2    RiverWidth/StartRiver
RoadLineTo2    DrawRiver
TaxiMoveTo     TwyWidth/StartTwy
TaxiLineTo     DrawTwy
RotatedCall    RotCall
TransformCall  TransRotCall
LayerCall/RunwayCall PriorityCall
Monitor3D      Jump3Ranges
Bitmap         TextureFile
RepeatBitmap   MoveTexture
Inst_7D        ResetTexture
MoveTexture    MapTexture
Palette        PaletteFile
BitmapMode     PaletteMask
Smoothing      ImageSmoothing

NOTE: The name MoveTexture is assigned to completely different instructions in SCASM and FSASM!

BCD numbers for Frequencies

Frequencies in FS are coded using BCD numbers.

BCD stands for Binary Coded Decimals, and is a special format for storing decimal (mostly integer) numbers. Each digit is stored in 4 bits.

It is very easy to convert a decimal number into the BCD representation. The number is simply written in a decimal notation, but treated as a hexadecimal. In FSASM, it is sufficient to add a 'h':

2545 (decimal) = 2545h (BCD)

SCASM [v1.6] requires values for SetVar etc. to be decimal numbers. There are many ways of converting hex numbers into decimal format; one method is to use Windows Calculator in the scientific mode.

Because the first digit of frequencies is always 1, it is not coded at all. The rest of the frequency is multiplied by 100 and converted into BCD:

In SCASM: 125.45 (Mhz) -> 2545h -> 9541 (decimal) -> SetVar ( 7BE 9541 )
In FSASM: 125.45 (Mhz) -> 2545h -> SetVar vCOM1,2545h