nxu/graph.tal

252 lines
9.0 KiB
Tal

( graph.tal )
( )
( graphing calculator )
( EXPRESSIONS )
( )
( expressions use one byte for an id, and )
( zero or more bytes for data. )
( )
( ID NAME DATA DESCRIPTION )
( 00 var variable x )
( 01 lit const* literal value )
( 02 neg e1* -e1 )
( 03 pow e* k^ e^k )
( 04 add e1* e2* e1 + e2 )
( 05 sub e1* e2* e1 - e2 )
( 06 mul e1* e2* e1 * e2 )
( 07 div e1* e2* e1 / e2 )
( )
( const* is a fixed point value )
( e*, e1*, and e2* are addresses of expressions. )
( k^ is an unsigned integer )
|00 @System &vect $2 &wst $1 &rst $1 &eaddr $2 &ecode $1 &pad $1 &r $2 &g $2 &b $2 &debug $1 &halt $1
|20 @Screen &vect $2 &w $2 &h $2 &auto $1 &pad $1 &x $2 &y $2 &addr $2 &pixel $1 &sprite $1
|0000
( set up variables used to configure graphing )
@width $2 ( screen width in pixels )
@height $2 ( screen height in pixels )
@epsilon $2 ( graph value per pixel )
@xmin $2 ( min x graph coord )
@xmax $2 ( max x graph coord )
@ymin $2 ( min y graph coord )
@ymax $2 ( max y graph coord )
( we really want (xmax-xmin)*epsilon to exactly equal width )
( and similarly (ymax-ymin)*epsilon to exactly equal height )
( )
( this implies a square screen. for non-square screens we'll )
( need separate epsilons for x and y. )
( )
( variables used during graphing )
@step $2 ( current step size for drawing )
@expr $2 ( current equation being graphed )
@x0 $2 ( lower bound of x )
@x1 $2 ( upper bound of x )
@y0 $2 ( lower bound of y )
@y1 $2 ( upper bound of y )
|0100
( screen size )
#0200 .width STZ2
#0200 .height STZ2
( colors )
#0f0f .System/r DEO2
#0ff0 .System/g DEO2
#00ff .System/b DEO2
( set up screen device )
.width LDZ2 .Screen/w DEO2
.height LDZ2 .Screen/h DEO2
( default settings: -4.0 to +4.0 )
( #fc00 DUP2 .xmin STZ2 .ymin STZ2
#0400 DUP2 .xmax STZ2 .ymax STZ2 )
#0400
DUP2 .xmax STZ2 DUP2 .ymax STZ2
#0000 SWP2 SUB2
DUP2 .xmin STZ2 .ymin STZ2
( TODO: we probably want separate epsilons for x and y )
( TODO: validate that (xmax-xmin)*eps = width exactly )
x-range .width LDZ2 DIV2 .epsilon STZ2
( draw x and y axis on background )
draw-y-axis draw-x-axis
( prepare equation )
;x^3-2x+1 .expr STZ2
( ;0.5x^2-6 .expr STZ2 )
( set up starting parameters )
.xmin LDZ2 .ymin LDZ2 x-range
( graph the equation )
draw BRK
@x-range ( -> x-range* ) .xmax LDZ2 .xmin LDZ2 SUB2 JMP2r
@y-range ( -> y-range* ) .ymax LDZ2 .ymin LDZ2 SUB2 JMP2r
@hline ( x1* x2* y* )
#01 .Screen/auto DEO .Screen/y DEO2 OVR2 .Screen/x DEO2
SUB2 &xloop #02 .Screen/pixel DEO INC2 ORAk ?&xloop POP2 JMP2r
@vline ( y1* y2* x* )
#02 .Screen/auto DEO .Screen/x DEO2 OVR2 .Screen/y DEO2
SUB2 &yloop #02 .Screen/pixel DEO INC2 ORAk ?&yloop POP2 JMP2r
@center-x ( -> cx* ) .width LDZ2 #01 SFT2 JMP2r
@center-y ( -> cx* ) .height LDZ2 #01 SFT2 JMP2r
( TODO: gets weird with non-powers-of-2 )
@draw-y-axis ( -> )
#0000 .height LDZ2 center-x vline ( )
center-x #0010 SUB2k ,&lmid STR2 ( )
ADD2 ,&rmid STR2 ( )
.height LDZ2 STH2 ( [h*] )
#0100 .epsilon LDZ2 DIV2 ,&vstep STR2 ( [h*] )
,&vstep LDR2 STH2 ( [h* step*] )
&vloop ( [h* pos*] )
[ LIT2 &lmid $2 ] ( lmid* [h* pos*] )
[ LIT2 &rmid $2 ] ( lmid* rmid* [h* pos*] )
STH2kr vline ( [h* pos*] )
[ LIT2r &vstep $2 ] ADD2r ( [h* pos+step*] )
GTH2kr STHr ?&vloop ( [h* pos+step*] )
POP2r POP2r JMP2r ( )
( TODO: gets weird with non-powers-of-2 )
@draw-x-axis ( -> )
#0000 .width LDZ2 center-y hline ( )
center-y #0010 SUB2k ,&lmid STR2 ( )
ADD2 ,&rmid STR2 ( )
.width LDZ2 STH2 ( [w*] )
#0100 .epsilon LDZ2 DIV2 ,&hstep STR2 ( [w*] )
,&hstep LDR2 STH2 ( [h* step*] )
&hloop ( [w* pos*] )
[ LIT2 &lmid $2 ] ( lmid* [w* pos*] )
[ LIT2 &rmid $2 ] ( lmid* rmid* [w* pos*] )
STH2kr hline ( [w* pos*] )
[ LIT2r &hstep $2 ] ADD2r ( [w* pos+step*] )
GTH2kr STHr ?&hloop ( [w* pos+step*] )
POP2r POP2r JMP2r ( )
( recursive drawing procedure )
( )
( this draws the area [x,y] to [x+s,y+s]. )
( first it checks whether that area contains a point. )
( next it checks if s=1: )
( - if so we draw that point )
( - if not, we split into a 2x2 grid and recurse )
@draw ( x* y* s* -> )
STH2k .step STZ2 ( x* y* [s*] ; step<-s )
OVR2 OVR2 evaluate ?&hit ( x* y* [s*] )
POP2 POP2 POP2r JMP2r ( ; miss )
&hit ( x* y* [s*] )
STH2kr #0001 EQU2 ?&term ( x* y* [s*] )
( STH2kr .epsilon LDZ2 LTH2 ?&term ( x* y* [s*] ) )
LITr 01 SFT2r ( x* y* [h=s/2*] )
OVR2 OVR2 ( x* y* x* y* h* [h*] )
STH2kr draw ( x* y* [h*] ; south west )
OVR2 OVR2 STH2kr ADD2 ( x* y* x* y+h* [h*] )
STH2kr draw ( x* y* [h*] ; north west )
OVR2 STH2kr ADD2 OVR2 ( x* y* x+h* y* [h*] )
STH2kr draw ( x+h* y* [h*] ; south east )
STH2kr ADD2 SWP2 STH2kr ADD2 SWP2 ( x+h* y+h* [h*] )
STH2r draw ( ; upper-right )
JMP2r ( )
&term ( x* y* [s*] )
POP2r ( x* y* )
.ymax LDZ2 SWP2 SUB2 ( x* ymax-y* )
.epsilon LDZ2 SUB2 ( x* ymax-y-e* )
.epsilon LDZ2 DIV2 ( x* sy=(ymax-y-e)/e* )
.Screen/y DEO2 ( x* ; screen/y<-sy )
.xmin LDZ2 SUB2 ( x-xmin* )
.epsilon LDZ2 DIV2 ( x* sx=(x-xmin)/e* )
.Screen/x DEO2 ( ; screen/x<-sx )
#41 .Screen/pixel DEO ( ; screen/pixel<-41 )
JMP2r ( )
( determine if the given x and y intervals intersect )
( if they do, at least one point of the graph is in this region )
( if not, the entire region is empty. )
@evaluate ( x* y* -> bool^ )
( store epsilon and x/y intervals )
LITr -step LDZ2r ( x* y* [e*] )
DUP2 .y0 STZ2 ( x* y* [e*] ; y0<-y )
STH2kr x16-add .y1 STZ2 ( x* [e*] ; y1<-y+e )
DUP2 .x0 STZ2 ( x* [e*] ; x0<-x )
STH2r x16-add .x1 STZ2 ( ; x1<-x+e )
( evaluate our equation )
.expr LDZ2 eval ( x-iv** )
.y0 LDZ2 .y1 LDZ2 ( x-iv** y-iv** )
!iv-intersects ( result^ )
( requires .x0 and .x1 to already be set )
@eval ( expr* -> interval** )
LDAk #00 NEQ ?&o1 ( var ) POP2 .x0 LDZ2 .x1 LDZ2 JMP2r
&o1 LDAk #01 NEQ ?&o2 ( lit ) INC2 LDA2 DUP2 JMP2r
&o2 LDAk #02 NEQ ?&o3 ( neg ) INC2 LDA2 eval !iv-negate
&o3 LDAk #03 NEQ ?&o4 ( pow ) INC2 STH2k LDA2 eval STH2r INC2 INC2 LDA !iv-pow
&o4 LDAk #04 NEQ ?&o5 ( add ) ;iv-add !binop
&o5 LDAk #05 NEQ ?&o6 ( sub ) ;iv-sub !binop
&o6 LDAk #06 NEQ ?&o7 ( mul ) ;iv-mul !binop
&o7 #0000 DIV ( TODO: div )
@binop ( addr* op* -> interval** )
STH2 INC2 STH2k ( addr+1* [op* addr+1*] )
LDA2 eval ( lhs** [op* addr+1*] )
STH2r INC2 INC2 LDA2 eval ( lhs** rhs** [op*] )
STH2r JMP2 ( result** )
@clear ( -> )
#0000 ;expr STA2
;arena ;next STA2
JMP2r
@alloc ( id^ size* -> addr* )
;next LDA2k STH2k ( id^ size* next* addr* [addr*] )
ROT2 ADD2 SWP2 STA2 ( id^ [addr*] ; next<-addr+size )
STH2kr STA ( [addr*] ; addr<-id )
STH2r JMP2r ( addr* )
@alloc-const ( const* -> e* )
#01 #0003 alloc ( const* addr* )
STH2k INC2 STA2 ( [addr*] ; addr+1<-const )
STH2r JMP2r ( addr* )
@alloc-lit ( const* -> e* )
#01 #0003 alloc ( const* addr* )
STH2k INC2 STA2 ( [addr*] ; addr+1<-const )
STH2r JMP2r ( addr* )
@alloc-neg ( e0* -> e* )
#02 #0003 alloc ( e0 addr* )
STH2k INC2 STA2 ( [addr*] ; addr+1<-e0* )
STH2r JMP2r ( addr* )
@0.5x^2-6 05 =0.5x^2 =six
@0.5x^2 06 =x^2 =0.5
@x^2 03 =x 02
@0.5 01 0080
@six 01 0600
@x^3-2x+1 04 =x^3-2x =one
@x^3-2x 05 =x^3 =2x
@one 01 0100
@x^3 03 =x 03
@2x 06 =x =two
@two 01 0200
~interval.tal
@x 00
@next :arena
@arena $1000