System information

+---------------------------------+
High | |
Memory | FDOS (BDOS + BIOS) |
FBASE: | |
+---------------------------------+
| |
| CCP |
CBASE: | |
+---------------------------------+
| |
| TPA |
TBASE: | |
+---------------------------------+
| |
| SYSTEM PARAMETERS |
BOOT: | |
+---------------------------------+
Figure 5-1. CP/M Memory Organization
The exact memory addresses corresponding to BOOT, TBASE, CBASE, and FBASE vary from
version to version and are described fully n Section 6. All standard CP/M versions assume
BOOT=0000H, which is the base of random access memory. The machine code found at location
BOOT performs a system warm start, which loads and initializes the programs and variables
necessary to return control to the CCP. Thus, transient programs need only jump to location
BOOT to return control to CP/M at the command level. further, the standard versions assume
TBASE=BOOT+0100H, which is normally location 0100H. The principal entry point to the
FDOS is at location BOOT+0005H (normally 0005H) where a jump to BASE is found. The
address field at BOOT+0006H (normally 006H) contains the value of FBASE and can be used to
determine the size of available memory, assuming that the CCP is being overlaid by a transient
program.
5.1 Introduction CP/M Operating System Manual
5-2