Geneve logical memory map

The logical address map determines which devices or memory areas appear in the logical address space. These are the addresses as seen from the CPU or the program that is run, but they need not correspond to the same physical address at all times. The correspondence is provided by the mapper.

Native mode

The native mode is also called MDOS mode. It is the mode which the Geneve initially boots to, typically with white letters on dark blue, and 80 column display.

0000	Reserved	Operating system
0400	Free space	Onboard memory or expansion
2000
4000
6000
8000
A000
C000
E000
F000	On-chip memory	Hides mapped page
F100	Video ports
F108	Keyboard
F110	Mapper
F120	Sound chip
F130	Clock chip
F140	Free space	Onboard memory or expansion
F800
FFF8
FFFA	Decrementer
FFFC	NMI vector
FFFE

GPL mode

The GPL mode is the compatibility mode, which is provided to run TI-99/4A programs.

0000	GPL interpreter	Operating system
2000	Free space 8 KiB	Onboard memory or expansion
3000
3FFE
4000	DSR space	Normally used by the GeneveOS DSR
6000	Cartridge ROM contents	Loaded from disk
8000	Mapper registers
8008	Keyboard
8010	Clock chip
8020	Free space
8400	Sound chip
8600	External bus	Any device in the PEB that maps to this address
8800	Video ports
9000	Speech synthesizer	if plugged into the PEB
9800	GRAM
A000	Free space 24 KiB
C000
E000
F000	On-chip memory	Hides mapped page
F100	Free space
FFFA	Decrementer
FFFC	NMI vector
FFFE