128,129



     drawn, this value is decremented. When the byte equals zero, the
     line is complete (drawn).

---------------------------------------------------------------------

User and/or BASIC page zero RAM begins here. Locations 128 to 145
($80 to $91) are for BASIC program pointers; 146 to 202 ($92 to $CA)
are for miscellaneous BASIC RAM; 203 to 209 ($CB to $D1) are
unused by BASIC, and 210 to 255 ($D2 to $FF) are the floating point
routine work area. The Assembler Editor cartridge uses locations 128
to 176 ($80 to $B0) for its page zero RAM. Since the OS doesn't use this
area, you are free to use it in any non-BASIC or non-cartridge
environment. If you are using another language such as FORTH,
check that program's memory map to see if any conflict will occur.
See COMPUTE!'s First Book of Atari, pages 26 to 53, for a discussion
of Atari BASIC structure, especially that using locations 130 to 137
($82 to $89). Included in the tutorials are a memory analysis, a line
dump, and a renumber utility. See also De Re Atari, BYTE, February
1982, and the locations for the BASIC ROM 40960 to 49151 ($A000 to
$BFFF).

128,129        80,81          LOMEM
     Pointer to BASIC's low memory (at the high end of OS RAM
     space). The first 256 bytes of the memory pointed to are the token
     output buffer, which is used by BASIC to convert BASIC
     statements into numeric representation (tokens; see locations
     136, 137; $88, $89). This value is loaded from MEMLO (locations
     743, 744; $2E7, $2E8) on initialization or the execution of a NEW
     command (not on RESET!). Remember to update this value when
     changing MEMLO to reserve space for drivers or buffers.
     When a BASIC SAVE is made, two blocks of information are
     written: the first block is the seven pointers from LOMEM to
     STARP (128 to 141; $80 to $8D). The value of LOMEM is
     subtracted from each of these two-byte pointers in the process, so
     the first two bytes written will both be zero. The second block
     contains the following: the variable name table, the variable
     value table, the tokenized program, and the immediate mode
     line.
     When a BASIC LOAD is made, BASIC adds the value at MEMLO
     (743, 744; $2E7, $2E8) to each of the two-byte pointers SAVEd as
     above. The pointers are placed back in page zero, and the values
     of RUNSTK (142, 143; $8E, $8F) and MEMTOP (144, 145; $90,
     $91) are set to the value in STARP. Then 256 bytes are reserved
     above the value in MEMLO for the token output buffer, and the
     program is read in immediately following this buffer.
     When you don't have DOS or any other application program
     using low memory loaded, LOMEM points to 1792 ($700). When