Appendix 10

BAS128 information

Disc-based BBC BASIC -- BAS128

This version of BBC BASIC, supplied on the Welcome disc, gives the user

access to a full 64K of memory for BASIC programs.

BASl28 is loaded by typing:

*BAS128 [RETURN]

The screen will be cleared and the banner BBC BASIC will appear together

with the message Bytes free 64K.

The > prompt will be displayed and commands may be issued in the same way

as for ROM-based BBC BASIC.

If you are a new user of Master series computers you should read the section of

this manual about BASIC before attempting to use this software. If you are

familiar with BBC BASIC and intend to write your own programs, you may

need to be aware of the technical differences between the ROM-based and

dise-based versions. The key point is that this disc-based version is loaded into

the RAM area which would usually be occupied by a user program. The 64K

area of additional 'sideways' RAM is then made available for user prograrns.

The detailed differences between the two BASICs are as follows:

1. When using BASl28, the 64K of additional memory pretends to be a

continuous address space above the normal 64K address space of the computer.

Thus addresses &000000 to &00FFFF refer to normal memory and addresses

&010000 to &0IFFFF refer to the 64K bytes of sideways RAM.

PAGE defaults to &10000.

HIMEM defaults to &20000.

Similarly, LOMEM and TOP are addressed in this way.

2. Statements such as:

DIM code 100

App 10.1