TITLE FCOL4 MODULE FCOL4 AREADEF PROG,[CODE,PIC,READ],DOUBLE AREADEF DATA,[DATA,PIC],DOUBLE DEFSB DATA EXPORTC STOPCODE4,STARTCODE4,FCOL4 IMPORTC OSWord='BBC'.'OSWord',OSFile='BBC'.'XOSFile' mc EQU 16 ; maximum # of colours AREA PROG STOPCODE4 ; stops the fchost program in the BBC MOVQW 2,bbc ADDR bbc,TOS ADDR @255,TOS CXP OSWord RXP 4 host DCS "$.graphics.utils.hostfcol" STARTCODE4 ; initializes for FCOL4 & starts the BBC host code ; SUBROUTINE STARTCODE(nx,mscale,mode,nc,kols,nds) ; nx is # columns ; mscale is the scale of points to graphics coords (0 - 1023) ; mode is MODE of plot ; nc is # of colours & iteration bounds ; kols are colours ; nds are iteration bounds SPRD FP,TOS LPRD FP,12(SP) ; load the BBC code first time through CMPQB 0,host BEQ fc0 MOVQD -1,bbc+4 ADDR bbc,TOS MOVZBD host,TOS ADDR host+1,TOS ADDR @255,TOS CXP OSFile MOVQB 0,host fc0 MOVD 0(12(FP)),R0 ;nc MOVD 16(FP),R1 ;addr. kols MOVD 20(FP),R2 ;addr. nds MOVQW -1,bnd[R0:W] ;guard band fc1 MOVW -4(R2)[R0:D],bnd-2[R0:W] ;store bands MOVW -4(R1)[R0:D],col-2[R0:W] ;store colour ACBD -1,R0,fc1 MOVQD 0,buf ADDR buf,R1 ADDR 4(R1),R2 ADDR @15,R0 MOVSD ;clear buf MOVD 0(8(FP)),R7 ;mode MOVB R7,mode MOVD 0(0(FP)),R0 ;nx MOVD R0,R1 ;copy of nx ADDD R0,R0 ADDR @0[R0:W],nx4 ;keep nx*4 MULW R7,R0 ADDW =22,R0 ASHW =-3,R0 MOVW R0,bbc ;# bytes to send per row ADDQD -1,R1 ;nx-1 MOVD R1,R2 ;ditto CMPQB 1,R7 BNE fc2 ANDB =15,R1 ASHD =-4,R2 BR fc3 fc2 ANDB =7,R1 ASHD =-3,R2 fc3 MOVB R1,byte ;#colour bit pairs in last word ADDR buf[R2:D],disp ;address of last word MOVD 0(4(FP)),R1 ;mscale ASHD =-2,R1 ;convert to pixels (0 - 255) MOVB R1,stc+5 ;# rows for each Y DIVW R7,R1 MOVB R1,stc+4 ;# columns for each X MOVB R7,stc+6 ;mode MOVW =#X0200,R0 BSR rdbyt ;get byte @ &200 in BBC MOVB R1,stc+2 MOVW =#X0201,R0 BSR rdbyt ;get byte @ &201 in BBC MOVB R1,stc+3 MOVQW 7,stc ;7 bytes in initialization of BBC code MOVW =#X0200,R0 MOVQB 0,R1 BSR sndbyt ;put 0 in &200 in BBC MOVW =#X0201,R0 MOVB =#X2D,R1 BSR sndbyt ;put &2D in &201 in BBC ADDR stc,TOS ADDR @255,TOS CXP OSWord ;start BBC code LPRD FP,TOS RXP 4 rdbyt ; get byte from BBC MOVQD -1,temp MOVW R0,temp ADDR temp,TOS MOVQD 5,TOS CXP OSWord MOVB temp+4,R1 RET 0 sndbyt ; send byt to BBC MOVQD -1,temp MOVW R0,temp MOVB R1,temp+4 ADDR temp,TOS MOVQD 6,TOS CXP OSWord RET 0 FCOL4 ; SUBROUTINE FCOL4(ib) ; ib is the array of iteration counts (integer *2) MOVD 8(SP),R0 MOVD 0(R0),R0 ;addr of ib MOVD nx4,R1 ADDD R0,R1 ;end of ib MOVD disp,R6 ADDR bnd,R2 ;initial boundary address MOVB byte,R5 ;count of colour bits CMPQB 1,mode BNE n0 ;mode 2 m0 MOVQD 0,R4 ;clear accumulator m1 ADDQD -4,R1 MOVW 0(R1),R3 ;# iterations for point m2 ADDQD 2,R2 CMPW 0(R2),R3 BLS m2 ;bound is too big m3 ADDQD -2,R2 CMPW 0(R2),R3 BHI m3 ;bound is too low ADDD R4,R4 ADDD R4,R4 ;shift accumulator ORB col-bnd(R2),R4 ;insert new colour ADDQB -1,R5 BCS m1 ;accumulator not full MOVD R4,0(R6) ;store accumulator in O/P buffer ADDQD -4,R6 MOVB =15,R5 CMPD R1,R0 BHI m0 ;loop over points snd ADDR bbc,TOS ADDR @255,TOS CXP OSWord RXP 4 n0 MOVQD 0,R4 ;clear accumulator n1 ADDQD -4,R1 MOVW 0(R1),R3 ;# iterations for point n2 ADDQD 2,R2 CMPW 0(R2),R3 BLS n2 ;bound is too big n3 ADDQD -2,R2 CMPW 0(R2),R3 BHI n3 ;bound is too low ADDD R4,R4 ADDD R4,R4 ADDD R4,R4 ADDD R4,R4 ;shift accumulator ORB col-bnd(R2),R4 ;insert new colour ADDQB -1,R5 BCS n1 ;accumulator not full MOVD R4,0(R6) ;store accumulator in O/P buffer ADDQD -4,R6 MOVQB 7,R5 CMPD R1,R0 BHI n0 ;loop over points BR snd ;send data to BBC AREA DATA nx4 ALLOCD 1 mode ALLOCB 1 byte ALLOCB 1 disp ALLOCD 1 bnd ALLOCW mc+1 col ALLOCW mc bbc ALLOCW 41 buf EQU bbc+2 temp ALLOCW 3 stc ALLOCW 4 END