ovm - ARCHIVED - A stack based virtual machine to act as a target for other programming languages

Age	Commit message (Collapse)	Author
2024-04-14	Moved struct definitions lib/inst.h -> lib/prog.h	Aryadev Chavali
	This means if I write the new assembler in another language I only need to FFI this header rather than all the functions as well which may not be as useful.
2024-04-12	Fixing build problems due to endian.h	Aryadev Chavali
	Have to define _DEFAULT_SOURCE before you can use the endian conversion functions. As most standard library headers use features.h, and _DEFAULT_SOURCE must be defined before features.h is included, we have to include base.h before other headers.
2023-11-03	Defined a `program` structure	Aryadev Chavali
	Essentially a "program header", followed by a count, followed by instructions. Provides a stronger format for bytecode files and allows for better bounds checking on instructions.
2023-11-02	Introduced instructions to engage with a call stack	Aryadev Chavali
	Essentially you may "call" an absolute program address, which pushes the current address onto the call stack. CALL_STACK does the same thing but the absolute program address is taken from the data stack. RET pops an address off the call stack then jumps to that address.
2023-11-02	Removed instruction OP_JUMP_REGISTER	Aryadev Chavali
	Not necessary when you can just push the relevant word onto the stack then just do OP_JUMP_STACK.
2023-11-02	Small fixes	Aryadev Chavali

2023-11-01	Added instructions for MALLOC_STACK and SUB	Aryadev Chavali
	MALLOC_STACK is a stack based version of MALLOC, SUB does subtraction.
2023-11-01	Added stack based versions of MSET and MGET	Aryadev Chavali
	Essentially they use the stack for their one and only operand. This allows user level control, in particular it allows for loops to work correctly while using these operands.
2023-11-01	Added instruction to get the size of some allocation	Aryadev Chavali
	This will allow for more library level code to be written. For example, say you wanted to write a generic byte level reversal algorithm for dynamically sized allocations. Getting the size of the allocation would be fundamental to this operation.
2023-11-01	Added instructions for allocating, setting, getting and deleting heap memory	Aryadev Chavali
	One may allocate any number of (bytes\|hwords\|words), set or get some index from allocated memory, and delete heap memory. The idea is that all the relevant datums will be on the stack, so no register usage. This means no instructions should use register space at all (other than POP, which I'm debating about currently). Register space is purely for users.
2023-11-01	Introduced a new mathematical operator MULT	Aryadev Chavali
	Thankfully multiplication, like addition, is the same under 2s complement as it is for unsigned numbers. So I just need to implement those versions to be fine.
2023-11-01	Removed OP_EQ signed versions as they're useless	Aryadev Chavali
	A negative number under 2s complement can never be equal to its positive as the top bit must be on. If two numbers are equivalent bit-by-bit then they are equal for both signed and unsigned numbers.
2023-10-31	Moved inst module to lib	Aryadev Chavali
	As it has no dependencies on vm specifically, and it's more necessary for any vendors who wish to target the virtual machine, it makes more sense for inst to be a lib module rather than a vm module.