Page:NBS Technical Note 11176 (1983) (IAutilityprogramsf1176dick).djvu/20

 Lines 8000-8090 : HIIRES SINGLE CHARACTER GRAPHICS

These routines draw the hires single characters that are input either by using the Hershey vectors or the cursor control. Lines 8000-8050 draw the box for the display of the character as illustrated in Fig. 1. In this representation, each dot corresponds to one unit in the character. Lines 8060-8090 plot the figure from the decoded character string values. Line 8060 sets the magnification, M, to 5, and plots the left and right boundaries relative to the center of the display ( x=140 ,y=80 ). Line 8070 sets the next point as the center of the left marker. Subsequent values of X and Y are then plotted with the appropriate pen control by the remainder of the routine. The current location is stored in the variables X` and Y1.

Lines 9000-9010 : CATALOG

This routine lists the catalog of the disk currently specified as the input disk, DI.

Line 10000 : END

This is a standard exit routine.

Lines 11000-11060 : THE HIRES MEMORY FLIP ROUTINE

This routine copies the contents of hires page 1 to hires page 2 or vice versa. The starting address, the ending address, and the first address of the destination field are read from the data statement at line 11060. Depending on the state of the memory flag, MF, page 1 is sent to page 2 (MF=0) or vice versa (MF=1). The microprocessor's y and x register locations are zeroed by the POKE statements of line 11030 and the Program Counter is initialized to point to the Apple Monitor MOVE routine ($FE2C) which is then called by the Apple Monitor GO routine ($FEB5).

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