User`s guide

The fourth and final stage in the cold start procedure is performed by the BIOS
Cold Start function, Function 0. The entry point to this function is located at
BIOS -base as described in Section 1.4. The BIOS Cold Start function begins by
performing any remaining hardware initialization, and initializing Page Zero. To
initialize Page Zero, the BIOS Cold Start function places a jump to BIOS base + 3,
the BIOS Warm Start entry point, at location OOOOH, and a jump to BDOS-base + 6,
the BDOS entry point, at location 0005H in memory.
The BIOS Cold Start function completes the fourth stage by loading the CCP into
the TPA region of memory and passing control to it. The CCP can be loaded from
one of two locations. If there is sufficient space in the system tracks for the CCP, it
is usually loaded from there. If there is not enough space in the system tracks, the
BIOS Cold Start function can read the CCP from the file CCP.COM.
On some banked systems, the CCP is also copied to an alternate bank, so that
warm start operations can copy the CCP into the TPA from memory. This speeds up
the system warm start operation, and makes it possible to warm start the system
without having to access a system disk.
When the CCP gains control, it displays a prompt that references the default disk.
If a PROFILE.SUB submit file is present on the default drive, the CCP executes this
submit file before prompting the user for a command.
At this point, the cold start procedure is complete. Note that the user number is
set to zero when CP/M 3 is cold started. However, the PROFILE submit file can set
the user number to another value if this is desirable.
The cold start procedure is designed so that the system tracks need to be initialized
only once. This is accomplished because the system track routines are independent of
the configured memory size of the CP/M 3 system. The Cold Boot Loader loads
CPMLDR into a constant location in memory. This location is chosen when the
system is configured. However, CPMLDR locates the BDOS and BIOS system com-
ponents in memory as specified by the CPM3.SYS file. The CCP always executes at
location 100H in the TPA. Thus, CP/M 3 allows the user to generate a new system
with GENCPM, and then run it without having to update the system tracks of the
system disk.
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1.6 System Operation CP/M 3 Programmer's Guide