Fast (& accurate) Arc circle

[Yann]

Fast Arc

Draws an arc circle into any Grob, or into Graphic Area if none provided.
Many Thanks to Cyrille de Brebisson for providing sample source code with many innovative ideas.

Fast Arc V1.0 : Binaries for HP48 S/SX/G/GX and HP49 G/G+, HP50G & HP48GII
Code Size : 895.5 Bytes; Checksum : HP48 : #933Eh; HP49 : #F119h

Input :
6 : Grob (<-- Optional, if none provided, will draw into Graphic Area)
5 : X0
4 : Y0
3 : Radius
2 : Start Bearing (°)
1 : End Bearing (°)

Notes :
(0,0) is upper left.
Bearing convention is clockwise : 0° is North (or Front)
X0 & Y0 can be negative
All values are limited to 250.000 (Grob Width/Height, X0, Y0),
except Radius which is limited to 65.000.

Here follows some benchmark numbers :

Name	Input	HP48SX	HP48GX	HP50G*
30pixels, Quarter circle	X=65,Y=32,R=30,S=90,E=180	73ms	40ms	25ms
30pixels, Half circle	X=65,Y=32,R=30,S=90,E=270	81ms	46ms	26ms
30pixels, Full circle	X=65,Y=32,R=30,S=90,E=90	107ms	57ms	30ms
60pixels, Full circle	X=30,Y=-10,R=60,S=90,E=90	125ms	75ms	33ms
150pixels, 3/4 circle	X=65,Y=160,R=150,S=90,E=360	134ms	102ms	41ms

(*)Note : Thanks to Jacob Wall for providing HP50G results


PureCode version (without the header) show significant performance gains, as most of the time is in fact spent in the header (checking and reordering input for ASM code).
For 48GX, the 30pixels half-circle is in fact done in 14ms, while the quarter circle only needs 9ms. That means the header takes about 31ms for itself.
PureCode, however, is only usable for developers (too risky for end-user, see included doc).


This version is considered reasonably accurate.
For comparison with previous "approximative" versions, some screenshots follows :

30pixels half circle; starts and ends correctly
(X=32,Y=32,R=30,S=90,E=270)


(X=68,Y=32,R=30,S=90,E=270)


Large Half-circle : ends correctly
(X=168,Y=32,R=100,S=90,E=270)


Three-Quarters small circle : ends correctly
(X=65,Y=44,R=15,S=90,E=0)