Note that also ROM (Read-Only Memory) circuits are emulated using this component. A ROM circuit is a RAM with writeProtect = true.
The following example shows how to interactively add a ram component to a machine:
$ gxemul -V
..
GXemul> add machine
GXemul> add mainbus machine0
GXemul> root
root
\-- machine0
\-- mainbus0
accuracy = cycle
step = 0
GXemul> add ram mainbus0
GXemul> ram
ram0 (0 bytes at offset 0)
data = (custom)
lastDumpAddr = 0
memoryMappedAddrMul = 0x1
memoryMappedBase = 0
memoryMappedSize = 0
step = 0
writeProtect = false
GXemul> ram0.memoryMappedSize = 0x400000
GXemul> root
root
\-- machine0
\-- mainbus0
\-- ram0 (4 MB at offset 0)
accuracy = cycle
step = 0
GXemul>
Source code for this component can be found here (and Doxygen documentation here).