88,89



     LSB and MSB of the area to be cleared into these locations. Your
     routine should always end on a $FF boundary (RAMTOP indicates
     the number of pages). Remember to POKE back the proper screen
     locations or use a GRAPHICS command immediately after doing
     so to set the screen right. Try this:

     10  BOTTOM = 30000: TOP = 36863: REM
        LOWEST AND HIGHEST ADDRESS TO CLEA
        R = $7530 & $8FFF
     20  RAMTOP = PEEK(106): POKE 106, INT
        (TOP + 1 / 256)
     30  TEST = INT(BOTTOM / 256): POKE89,
         TEST
     40  POKE 88. BOTTOM - 256 * TEST
     50  PRINT CHR$(125): POKE 106, RAMTOP
     60  GRAPHICS 0

     This will clear the specified memory area and update the address
     of screen memory. If you don't specify TOP, the CLEAR SCREEN
     will continue merrily cleaning out memory and, most likely, will
     cause your program to crash. Use it with caution.
     Here's a means to SAVE your current GR.7 screen display to disk
     using BASIC:

     1000  SCREEN = PEEK(88) + PEEK(89) *
          256
     1010  OPEN #2,8,0,"D:picturename"
     1020  MODE = PEEK(87): PUT #2, MODE:
          REM SAVE GR. MODE
     1030  FOR SCN = 0 TO 4: COL PEEK(70
          8 + SCN): PUT #2,COL: NEXT SCN:
          REM SAVE COLOR REGISTERS
     1040  FOR TV = SCREEN TO SCREEN + 319
          9:BYTE = PEEK(TV): PUT #2, BYTE:
          NEXT TV: CLOSE #2

     To use this with other screen modes, you will have to change the
     value of 3199 in line 1040 to suit your screen RAM (see the chart
     above). For example, GR.7 + 16 would require 3839 bytes (3840
     minus one). You can use the same routine with cassette by using
     device C:. To retrieve your picture, you use GET#2 and POKE 
     commands. You will, however, find both routines very slow. Using
     THE CIO routine at 58454 ($E456) and the IOCBs, try this machine
     language save routine:

     10  DIM ML$(10): B$(10): GR.8+16
     20  B$ = "your picture name":Q = PEEK
        (559)
     30  FOR N = 1 TO 6: READ BYTE: ML$(N,