The X-Philes (2nd Revision)

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Text File | 1995-03-31 | 4.9 KB | 276 lines

%%HP: T(3)A(D)F(.); "********************** * Name: Line * draw/clear/toggle * line in a GROB * Interface: * gr #x1 #y1 #x2 #y2 * --> * #x1 must be < #x2. * Error Exits: none * Alters: * CPU - A,B,C,D,D0, * D1,R0,R1,R2,R3,R4, * P,CRY * RAM - gr and coord. * popped * Calls: * =POP# =SAVPTR * =PopASavptr * =GETPTRLOOP * Stk Levels: * 1 * Notes: * std. DDA * The routine works * only on VDISP yet, * assuming x-size = * 131 (real 136 -> * 34 nibb/line). * !!! BANG TYPE !!! * History: * 05/20/92 DM * Implemented as * test for QIX. Q&D! * 07/11/92 DM * review, add spec. * cases, cond.ass. ********************** Toggle EQU 0 Set only On EQU 0 one to 1 Off EQU 1 at a time! sFlag EQU 5 ***** * Pop parameter,calc. * and check dx ***** GOSUB Pop# R3=A y2 GOSUB Pop# R2=A x2 GOSUB Pop# R1=A y1 GOSUB Pop# R0=A x1 *1* GOSBVL =PopASavptr ->grob GOSBVL =SAVPTR *1* D0=(5) =VDISP *1* ->->grob A=DAT0 A *1* ->grob D0=A ->grob A=R0 x1 C=R2 x2 C=C-A A dx=x2-x1 GONC dxok GOTO Exit Sorry,invalid order dxok R2=C dx ***** * Calculate ystep, * pointer to grob and * initial bit mask ***** D0=D0+ 15 ->x, Skip prlg,len,y *2* C=DAT0 A x *2* C=C+CON A,7 Force byte boundary *2* CSRB.F A *2* CSRB.F A *2* CSRB.F A *2* C=C+C A nibb/line LC(5) 34 *2* nibb/line D=C A ys D0=D0+ 5 ->pix,Skip x A=R1 y1 * unsigned C*=A (org.HP) B=0 A BCEX A Mul2 B=B-1 P GOC Mul3 C=C+A A GOTO Mul2 Mul3 ASL A P=P+1 ?P# 5 GOYES Mul2 P= 0 A=R0 x1,y1*nibb/line ASRB.F A ASRB.F A /=4 A=A+C A offs=x1/4+y1*nibb/line CD0EX ->pix C=C+A A +=offs D0=C ->nibb * Now some magic A=R0 x1 LC(1) 3 C=C&A B x1%4 C=C+CON B,13 +=13 P=C 0 LC(4) #1248 P=C 0 C=P 1 P= 0 B=C B mask IFNE Off B=-B-1 B OFF mask ENDIF ***** * Calculate dy, check * for special cases * dx=0,dy=0 or dx=dy ***** A=R1 y1 C=R3 y2 C=C-A A dy=y2-y1 GONC tstdxy D=-D A -ys C=-C A -dy tstdxy ST=0 sFlag A=R2 dx ?C=A A GOYES dxeqdy dx=dy ?A=0 A GOYES dxeq0 dx=0 ?C#0 A GOYES dxgtdy? dy<>0 * dy=0,set up x steps D1=A cnt = dx GONC dx1dy0 BET * dx=0,set up y steps dxeq0 ST=1 sFlag D1=C cnt=dy dx1dy0 A=0 A A=A+1 A dx=1 C=0 A dy=0 GONC dxdycok BET * dx=dy,set up x&y steps dxeqdy D1=A cnt=dx A=0 A dx=0 C=0 A dy=0 GOC dxdycok BET Exit GOVLNG =GETPTRLOOP ***** * Normal case, check * for dy>=dx, calc. e ***** dxgtdy? ?C<A A GOYES dxdyok ST=1 sFlag dy>dx,swap dx, dy ACEX A dxdyok D1=A cnt=dx dxdycok R2=A dx R3=C dy ASRB.F A dx/2 R4=A e ***** * The show begins... ***** plot A=DAT0 1 Read nibble IFNE On A=A!B B Set bit ENDIF IFNE Off A=A&B B Clear bit ENDIF IFNE Toggle C=A B A=A!B B C=C&B B A=A-C B ENDIF DAT0=A 1 Write nibble D1=D1- 1 --cnt GOC Exit A=R4.F A e C=R3.F A dy A=A+C A e+=dy R4=A.F A e C=R2.F A dx ?ST=1 sFlag GOYES allwy ?A<C A GOYES xstep e>=dx A=A-C A e-=dx R4=A.F A e CD0EX ->pix C=C+D A ->next row D0=C ->pix xstep B=B+B B mask<<=1 IFNE (On)+(Toggle) GONC plot LC(2) #11 init.mask ENDIF IFNE Off GOC plot LC(2) #EE ENDIF B=C B mask D0=D0+ 1 ->nxt nibb GONC plot BET allwy ?A<C A GOYES ystep e>=dx A=A-C A e-=dx R4=A.F A e B=B+B B mask <<= 1 IFNE (On)+(Toggle) GONC ystep LC(2) #11 init. mask ENDIF IFNE Off GOC ystep LC(2) #EE ENDIF B=C B mask D0=D0+ 1 ->nxt nibb ystep CD0EX ->pix C=C+D A ->next row D0=C ->pix GOTO plot Pop# GOVLNG =POP#"