7.2. MEMORY SPACE.

It is possible for the Sound-CPU to address 64K bytes of memory.
Memory space is divide up according to purpose. From address
0000, 512 bytes are divided into two pages of 256-bytes units,
called zero page and page one. It is possible to access data
within these regions by means of numerous address modes, such
as direct page addresing, etc.
Page one is taken up by the stack.


7.2.1. Direct Pages (Zero Page, Page One)

By means of setting or resetting the direct page (P) flag
within the program status ward. it is possible to disignate 
whether zero page or page one is to be made the direct page.
it is set up such that the data within this page can be treated
with fewer bytes, at highter speed and with more numerous types
of commands and addressing modes.

   Stack Area
   ----------

   The stack region is established in the RAM region within page
   one. The uppermost byte of the stack address is fixed at 01.
   The lowermost byte of the stack address must be given its
   initial setting by the program.

7.2.2. Uppermost Page

Internal ROM Region

A mask ROM is installed within the Sound-CPU from FFC0H- FFFF. There
is a program in it which transmits data from the ROM cassette to the
256K bit RAM throuh the SCPU. This region is used by means of reset.