Re: Running generated machine code

[eterps]

Ah, yes that was a bit silly (the Rosettacode example works in a different 
way). I changed it to:
    
    
    import posix
    
    const
      prot = PROT_READ or PROT_WRITE or PROT_EXEC
    
    when defined(macosx) or defined(bsd):
      const MAP_ANONYMOUS = 0x1000
    else:
      var
        MAP_ANONYMOUS {.importc: "MAP_ANONYMOUS", header: "<sys/mman.h>".}: cint
    
    type
      IntToInt = proc(num: uint32): uint32 {.nimcall.}
    
    var code = [
      0x48'u8, 0x89'u8, 0xf8'u8,             # mov rax, rdi
      0x48'u8, 0x83'u8, 0xc0'u8, 0x00'u8,    # add rax, 4
      0xc3'u8                                # ret
    ]
    var mem = mmap(nil, code.len, prot, MAP_PRIVATE or MAP_ANONYMOUS, -1, 0)
    copyMem(mem, addr code[0], code.len)
    
    var add4 = cast[IntToInt](mem)
    echo add4(3)
    
    discard munmap(mem, code.len)
    
    
    Run

It outputs '3' now, not the right answer yet, but at least no segfault. Thanks 
I'll look into this further.