UMC Memory Model

• Four Instructions: alloc and free, load and store
• One register type with archecture-dependent width: a:0
• add and sub allowed with one address register and one (un)signed integer “offset”

Examples

alloc a:0, 4
store a:0, u32:1 ; Store 4-byte integer into address register
load u32:1 ; Load it as a 32 bit integer
free a:0 ; Frees the memory allocated earlier. a:0 is now invalid

Rationale

Allocating and de-allocating memory is a common task, which if we are running in the UMC VM, can easily be delegated to the VM.

Questions:

• How do we allocate a block of memory large enough for a memory address if size is machine-dependent? A constant?