mal/impls/nasm

x86_64 NASM implementation

Notes and known issues:

• No library dependencies, only Linux system calls

• Simple readline implemented, just supporting backspace for editing

• Reference counting used for memory management. No attempt is made to find circular references, so leaks are possible. In particular defining a function with def! creates a circular reference loop.

• The exception/error handling just resets the stack and jumps to a handler, so does not release memory

• Memory is allocated by two fixed-size allocators (Cons and Array objects) which have limits specified in types.asm. If more memory is needed then this must currently be done at compile-time, but adding sys_brk calls could be done.

• The hash map implementation is just a list of key-value pairs. Moving symbols around in the core environment makes a significant difference (20-30%) to the performance test. A simple optimisation could be to move items when found to the start of the list so that frequently searched keys are nearer the front.

• conj function not yet implemented

• *env* symbol evaluates to current Environment.