high speed hplot from assembly
*******************************
*
* HPLOT XLOC,YLOC FROM ASSEMBLY
*
* INPUT : XLOC X COORD
* YLOC Y COORD
*
* OUTPUT: OR'D WITH SCREEN
*
*****************************
XBIT DFB #00
XBYTE DFB #00
MASKTEMP DFB #00
;-----------------------------
HPLOT
LDY YLOC
LDA TLO,Y
STA SLO
LDA THI,Y
STA SHI
LDA XLOC
LDY #00
CLC
DLOOPSV CMP #7 ;DIVIDE X COORDINATE BY 7
BCC DDONESV
SEC
SBC #7
INY
CLC
JMP DLOOPSV
DDONESV
TAX ;Division done, now get the proper bit value
LDA MASK,X
ORA (SHI),Y ;
STA (SHI),Y ;PUT ON SCREEN
RTS
MASK DFB #$01,#$02,#$04,#$08,#$10,#$20,#$40,#$80