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The task requires poking machine code directly into memory and executing it. The machine code is the architecture-specific opcodes which have the simple task of adding two unsigned bytes together and making the result available to the high-level language.

For example, the following assembly language program is given for x86 (32 bit) architectures:

This would translate into the following opcode bytes: <lang>139 68 36 4 3 68 36 8 195</lang>

Or in hexadecimal: <lang>8B 44 24 04 03 44 24 08 C3</lang>

Task

If different than 32-bit x86, specify the target architecture of the machine code for your example. It may be helpful to also include an assembly version of the machine code for others to reference and understand what is being executed. Then, implement the following in your favorite programming language:

Poke the necessary opcodes into a memory location.
Provide a means to pass two values to the machine code.
Execute the machine code with the following arguments: unsigned-byte argument of value 7; unsigned-byte argument of value 12; The result would be 19.
Perform any clean up actions that are appropriate for your chosen language (free the pointer or memory allocations, etc.)

AutoHotkey

MCode Tutorial (Forum Thread)

MCode4GCC (Forum Thread | GitHub) - An MCode generator using the GCC Compiler. <lang AutoHotkey>MCode(Var, "8B44240403442408C3") MsgBox, % DllCall(&Var, "Char",7, "Char",12) Var := "" return

http://www.autohotkey.com/board/topic/19483-machine-code-functions-bit-wizardry/

MCode(ByRef code, hex) { ; allocate memory and write Machine Code there

  VarSetCapacity(code, StrLen(hex) // 2)
  Loop % StrLen(hex) // 2
     NumPut("0x" . SubStr(hex, 2 * A_Index - 1, 2), code, A_Index - 1, "Char")

}</lang>

BBC BASIC

Works with: BBC BASIC for Windows

Note that BBC BASIC for Windows includes an 80386/80486 assembler as standard!

<lang bbcbasic> REM Claim 9 bytes of memory

     SYS "GlobalAlloc",0,9 TO code%

     REM Poke machine code into it
     P%=code%
     [OPT 0
     mov EAX, [ESP+4]
     add EAX, [ESP+8]
     ret
     ]

     REM Run code
     SYS code%,7,12 TO result%
     PRINT result%

     REM Free memory
     SYS "GlobalFree",code%
     END</lang>

C

<lang C>#include <stdio.h>

include <sys/mman.h>
include <string.h>

int test (int a, int b) {

 /*
      mov EAX, [ESP+4]
      add EAX, [ESP+8]
      ret
 */
 char code[] = {0x8B, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0xC3};
 void *buf;
 int c;
 /* copy code to executable buffer */
 buf = mmap (0,sizeof(code),PROT_READ|PROT_WRITE|PROT_EXEC,
            MAP_PRIVATE|MAP_ANON,-1,0);

 memcpy (buf, code, sizeof(code));
 /* run code */
 c = ((int (*) (int, int))buf)(a, b);
 /* free buffer */
 munmap (buf, sizeof(code));
 return c;

}

int main () {

 printf("%d\n", test(7,12));
 return 0;

}</lang>

COBOL

This solution is a 64-bit adaptation of the task, using the macOS ABI and 64-bit instructions. The assembly code in question is:

<lang Assembler>pushq %rbp movq %rsp, %rbp movl %edi, -0x4(%rbp) movl %esi, -0x8(%rbp) movl -0x4(%rbp), %esi addl -0x8(%rbp), %esi movl %esi, -0xc(%rbp) movl -0xc(%rbp), %eax popq %rbp retq </lang> The 64-bit "wrapper code" used by the PicoLisp and Go implementations have the parameters 7 and 12 baked into it, so I opted for a pure 64-bit implementation rather than manipulating the 64-bit stack to support the 32-bit instructions. <lang COBOL> >>SOURCE FORMAT IS FIXED

      IDENTIFICATION DIVISION.
      PROGRAM-ID. MC.
      DATA DIVISION.
      WORKING-STORAGE SECTION.
          01 INSTRUCTIONS.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'55'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'48'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'89'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'E5'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'89'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'7D'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'FC'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'89'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'75'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'F8'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'8B'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'75'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'FC'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'03'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'75'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'F8'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'89'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'75'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'F4'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'8B'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'45'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'F4'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'5D'.
             03 USAGE BINARY-CHAR UNSIGNED VALUE H'C3'.
          01 MMAP.
             03 MMAP-ADDR   USAGE POINTER VALUE NULL.
             03 MMAP-LEN    USAGE BINARY-LONG UNSIGNED VALUE 24.
             03 MMAP-PROT   USAGE BINARY-INT VALUE H'0007'.
             03 MMAP-FLAGS  USAGE BINARY-INT VALUE H'1002'.
             03 MMAP-FD     USAGE BINARY-INT VALUE -1.
             03 MMAP-OFFSET USAGE BINARY-LONG VALUE 0.
          03 CODE-PTR USAGE PROCEDURE-POINTER.
          01 ARG-A USAGE BINARY-INT VALUE 7.
          01 ARG-B USAGE BINARY-INT VALUE 12.
          01 RESULT USAGE BINARY-INT.
      LINKAGE SECTION.
          01 MACHINE-CODE PIC X(24).
      PROCEDURE DIVISION.
      MAIN SECTION.
          PERFORM SET-UP.
          CALL CODE-PTR USING
             BY VALUE ARG-A
             BY VALUE ARG-B
             RETURNING RESULT.
          DISPLAY RESULT.
          PERFORM TEAR-DOWN.
          STOP RUN.

      SET-UP SECTION.
          CALL 'mmap' USING
             BY VALUE MMAP-ADDR
             BY VALUE MMAP-LEN
             BY VALUE MMAP-PROT
             BY VALUE MMAP-FLAGS
             BY VALUE MMAP-FD
             BY VALUE MMAP-OFFSET
             RETURNING CODE-PTR.
          SET ADDRESS OF MACHINE-CODE TO CODE-PTR.
          MOVE INSTRUCTIONS TO MACHINE-CODE.

      TEAR-DOWN SECTION.
          SET ADDRESS OF MACHINE-CODE TO NULL.
          CALL 'munmap' USING
             BY VALUE CODE-PTR
             BY VALUE MMAP-LEN.

</lang>

Output:

+0000000019

Commodore BASIC

For Commodore computers, machine language routines are often written to increase speed of a program, provide functionality not otherwise provided for in BASIC, or execute code in the background. It is common to see machine language routines incorporated into BASIC programs for these purposes.

The machine code shown for adding two numbers targets the MOS 65xx/85xx architecture (6502, 6510, etc.) and is given as follows:

<lang>Assembly Hexadecimal Decimal

CLC 18 24 LDA $2000 AD 00 20 173 0 32 ADC $2001 6D 01 20 109 1 32 STA $2002 8D 02 20 141 2 32 RTS 60 96</lang>

The numbers to be added must be poked into locations $2000 and $2001 (8192 and 8193)
The machine code is called for execution at $2003 with the SYS statement. (Note, since we are using ADd with Carry, we should CLear the Carry flag first to be sure the result is accurate.)
The result is stored in location $2002 (8194).
The machine code must issue a RTS (ReTurn from Subroutine) to allow BASIC to continue.

Note: This example, using RAM space at $2000, provides a wide range of cross-compatibility across Commodore 8-bit models, and has been tested to work on the Commodore PET (32k), VIC-20 (28k), Commodore 64, Commodore Plus/4, and Commodore 128.

No memory management is performed in this example, which would protect the machine code from being overwritten by BASIC. There are more optimal memory locations for the machine code to reside that are not affected by BASIC, however, the locations of such are unique to each model. For example, the range from $C000 to $CFFF (49152 to 53247) on the Commodore 64 is one such ideal location since BASIC memory ends at $9FFF, and there is no overlapping ROM to interfere.

<lang gwbasic>10 print chr$(147); 15 ml=8192 20 if peek(ml+3)<>173 and peek(ml+12)<>96 then gosub 100 30 for ad=ml to ml+2:poke ad,0:next 40 poke ml,7:poke ml+1,12 50 print "before:";peek(ml+2) 60 sys ml+3 70 print "after:";peek(ml+2) 80 end 100 rem machine language loader 105 for ad=ml+3 to ml+13 110 read b 115 poke ad,b 120 next 125 return 8195 data 24 :rem clc 8196 data 173,0,32 :rem lda $2000 8199 data 109,1,32 :rem adc $2001 8202 data 141,2,32 :rem sta $2002 8205 data 96 :rem rts</lang>

Notes about Program

Line 20 checks to see if the ML routine has already been loaded into memory. If not, visit the loader routine.
Line 30 clears the memory locations (sets to zero) for the two addends and the sum.

Output:

BEFORE: 0
AFTER: 19

READY.
█

Common Lisp

<lang lisp>;;Note that by using the 'CFFI' library, one can apply this procedure portably in any lisp implementation;

in this code however I chose to demonstrate only the implementation-dependent programs.

CCL Allocate a memory pointer and poke the opcode into it

(defparameter ptr (ccl::malloc 9))

(loop for i in '(139 68 36 4 3 68 36 8 195)

  for j from 0 do
  (setf (ccl::%get-unsigned-byte ptr j) i))

Execute with the required arguments and return the result as an unsigned-byte

(ccl::ff-call ptr :UNSIGNED-BYTE 7 :UNSIGNED-BYTE 12 :UNSIGNED-BYTE)

Output = 19

Free the pointer

(ccl::free ptr)

SBCL

(defparameter mmap (list 139 68 36 4 3 68 36 8 195))

(defparameter pointer (sb-alien:make-alien sb-alien:unsigned-char (length mmap)))

(defparameter callp (loop for byte in mmap

                         for i from 0

do (setf (sb-alien:deref pointer i) byte) finally (return (sb-alien:cast pointer (function integer integer integer)))))

(sb-alien:alien-funcall callp 7 12)

(loop for i from 0 below 18 collect (sb-alien:deref ptr i))

(sb-alien:free-alien pointer)

CLISP

(defparameter mmap (list 139 68 36 4 3 68 36 8 195))

(defparameter POINTER (FFI:FOREIGN-ADDRESS (FFI:FOREIGN-ALLOCATE 'FFI:UINT8 :COUNT 9)))

(loop for i in mmap

  for j from 0 do
  (FUNCALL #'(SETF FFI:MEMORY-AS) i POINTER 'FFI:INT j))

(FUNCALL

(FFI:FOREIGN-FUNCTION POINTER

(LOAD-TIME-VALUE (FFI:PARSE-C-TYPE '(FFI:C-FUNCTION (:ARGUMENTS 'FFI:INT 'FFI:INT) (:RETURN-TYPE FFI:INT) (:LANGUAGE :STDC)))))

7 12)

(FFI:FOREIGN-FREE POINTER) </lang>

Cowgol

<lang cowgol>include "cowgol.coh";

Run machine code at cptr, given two 32-bit arguments,
return the value returned from EAX.

sub RunCode(cptr: [uint8], arg1: uint32, arg2: uint32): (rslt: uint32) is

   # Inline assembly is supported, so this whole rigmarole
   # is not even necessary. 
   # Though note that this (obviously) depends on the assembly back-end used.
   # Linux as uses AT&T syntax, so that's what I'm doing here.
   # Cowgol supports many processors but this will, obviously, only work
   # on x86. 
   
   @asm "pushl (",arg1,")";      # Push the two arguments on the stack
   @asm "pushl (",arg2,")";
   @asm "call *(",cptr,")";      # Call the code at the pointer
   @asm "movl %eax, (",rslt,")"; # Store the result in rslt
   @asm "popl %eax";             # Clean up the stack
   @asm "popl %eax";

end sub;

Store code in an array. This is enough to make it available.

var code: uint8[] := {139, 68, 36, 4, 3, 68, 36, 8, 195};

Use the function

print_i32(RunCode(&code as [uint8], 7, 12)); # this prints 7+12 = 19 print_nl();

As a demonstration, this shows it can be patched at runtime to multiply instead

code[4] := 247; code[5] := 100; print_i32(RunCode(&code as [uint8], 7, 12)); # this prints 7*12 = 84 print_nl();</lang>

Output:

19
84

D

In D you usually use a nicer asm {} statement for similar purposes.

Generally new operating systems forbid execution of any address unless it's known to contain executable code. This is a basic version that unlike the C entry executes from array memory. This may crash on some operating systems. <lang d>int test(in int a, in int b) pure nothrow @nogc {

   /*
   mov EAX, [ESP+4]
   add EAX, [ESP+8]
   ret
   */
   immutable ubyte[9] code = [0x8B, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0xC3];
   alias F = extern(C) int function(int, int) pure nothrow @nogc;
   immutable f = cast(F)code.ptr;
   return f(a, b); // Run code.

}

void main() {

   import std.stdio;

   test(7, 12).writeln;

}</lang>

Output:

Go

Translation of: C

This task requires the use of 'cgo' which enables Go to interface with C code by importing a pseudo-package called "C".

Although Go supports both 32-bit and 64-bit architectures, I'm writing this on a 64-bit Ubuntu 20.04 system. I'm therefore using x64 opcodes rather than the x86 (32-bit) opcodes listed in the task description.

There doesn't appear to be a way to cast a pointer to a native buffer to a Go function pointer so that the machine code can be run directly. I've therefore written a C function to perform this step and embedded it in the program which 'cgo' allows us to do. <lang go>package main

import "fmt"

/*

include <stdio.h>
include <stdlib.h>
include <sys/mman.h>
include <string.h>

typedef unsigned char byte; typedef byte (*mcfunc) (byte, byte);

void runMachineCode(void *buf, byte a, byte b) {

   mcfunc fp = (mcfunc)buf;
   printf("%d\n", fp(a, b));

}

/

import "C"

func main() {

   code := []byte{
       0x55, 0x48, 0x89, 0xe5, 0x89, 0x7d,
       0xfc, 0x89, 0x75, 0xf8, 0x8b, 0x75,
       0xfc, 0x03, 0x75, 0xf8, 0x89, 0x75,
       0xf4, 0x8b, 0x45, 0xf4, 0x5d, 0xc3,
   }
   le := len(code)
   buf := C.mmap(nil, C.size_t(le), C.PROT_READ|C.PROT_WRITE|C.PROT_EXEC,
       C.MAP_PRIVATE|C.MAP_ANON, -1, 0)
   codePtr := C.CBytes(code)
   C.memcpy(buf, codePtr, C.size_t(le))
   var a, b byte = 7, 12
   fmt.Printf("%d + %d = ", a, b)
   C.runMachineCode(buf, C.byte(a), C.byte(b))
   C.munmap(buf, C.size_t(le))
   C.free(codePtr)

}</lang>

Output:

7 + 12 = 19

Julia

Translation of: C

Julia cannot execute machine code directly, but can embed C and C++ with the Cxx library. <lang julia>using Cxx

cxx"""

include <stdio.h>
include <sys/mman.h>
include <string.h>

int test (int a, int b) {

 /*
      mov EAX, [ESP+4]
      add EAX, [ESP+8]
      ret
 */
 char code[] = {0x8B, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0xC3};
 void *buf;
 int c;
 /* copy code to executable buffer */
 buf = mmap (0,sizeof(code),PROT_READ|PROT_WRITE|PROT_EXEC,
            MAP_PRIVATE|MAP_ANON,-1,0);

 memcpy (buf, code, sizeof(code));
 /* run code */
 c = ((int (*) (int, int))buf)(a, b);
 /* free buffer */
 munmap (buf, sizeof(code));
 return c;

}

int main () {

 printf("%d\n", test(7,12));
 return 0;

} """

julia_function = @cxx main() julia_function() </lang>

Kotlin

Translation of: C

This task presents a number of issues for Kotlin Native which at the time of writing (August 2017) is still in the earlier stages of development:-

1. The language doesn't (yet) have an unsigned Byte type, though this is easily solved by subtracting 256 from unsigned values between 128 and 255 inclusive and then using the signed Byte type.

2. As far as x86 is concerned, the language is currently only targetting 64-bit platforms including Ubuntu 14.04 on which I'm writing this. Rather than rewrite the task using x64 opcodes, I've used the PicoLisp entry's 'glue code' to enable the 32-bit machine code to run on a 64-bit system.

3. There doesn't appear to be a way to cast a pointer to a native buffer to a Kotlin function pointer so that the machine code can be run. I've therefore written a 'one line' C helper function (in mcode.def) to perform this step and compiled it to a library (mcode.klib) so that it can be called from Kotlin code. <lang C>// mcode.def ---

static inline unsigned char runMachineCode(void *code, unsigned char a, unsigned char b) {

   return ((unsigned char (*) (unsigned char, unsigned char))code)(a, b);

}</lang>

<lang scala>// Kotlin Native version 0.3

import kotlinx.cinterop.* import string.* import mman.* import mcode.*

fun main(args: Array<String>) {

   memScoped {        
       val bytes = byteArrayOf(
           144 - 256,                            // Align
           144 - 256,
           106, 12,                              // Prepare stack
           184 - 256, 7, 0, 0, 0, 
           72, 193 - 256, 224 - 256, 32,
           80,
           139 - 256, 68, 36, 4, 3, 68, 36, 8,   // Rosetta task code
           76, 137 - 256, 227 - 256,             // Get result
           137 - 256, 195 - 256,
           72, 193 - 256, 227 - 256, 4,
           128 - 256, 203 - 256, 2,
           72, 131 - 256, 196 - 256, 16,         // Clean up stack 
           195 - 256                             // Return
       )
       val len = bytes.size    
       val code = allocArray<ByteVar>(len)
       for (i in 0 until len) code[i] = bytes[i]
       val buf = mmap(null, len.toLong(), PROT_READ or PROT_WRITE or PROT_EXEC,
                      MAP_PRIVATE or MAP_ANON, -1, 0) 
       memcpy(buf, code, len.toLong())
       val a: Byte = 7
       val b: Byte = 12
       val c = runMachineCode(buf, a, b)
       munmap(buf, len.toLong()) 
       println("$a + $b = ${if(c >= 0) c.toInt() else c + 256}")
   }

}</lang>

Output:

7 + 12 = 19

M2000 Interpreter

We can execute machine code, in a buffer for code. We can't push to stack and then call, we can use a buffer for data. If eax is non zero then error raised, with error number the eax number. When execute code the code buffer can't be used to write over. so we have to use a buffer for data for read/write data. This example perform these: At Datamem(1) put 500, eax=5100, eax add Datamem(1), eax add 5, store eax to Datamem(0). We have an option to clear eax, or use it to return value as error code. We have to leave all other registers, and stack as we found it. Both running in Wine (Linux 64bit) too

<lang M2000 Interpreter> Module Checkit {

     Buffer DataMem as Long*10
     Return DataMem, 1:=500    ' second Long
     Print Eval(DataMem, 1)+5100+5=5605
     \\ Now we do math executing machine code
     Buffer Code ExecMem as byte*1024
     Address=0
     EmbLong(0xb8, 5100) ' mov eax,5100
     EmbByteByte(0x83, 0xC0, 5) ' add  eax,0x5
     EmbByteLong(0x3,0x5, DataMem(1)) ' add eax, [DataMem(1)] 
     EmbLong(0xa3, DataMem(0)) ' mov [DataMem(0)], eax
     \\ split rem to execute xor eax eax (eax=0)
     Rem : EmbByte(0x31, 0xC0) ' xor eax, eax 
     Ret() ' Return
     \\  
     Try ok {
           Execute Code ExecMem, 0
     }
     \\If  Eax <>0 then we get error, so we read error as Uint()
     \\ Error read once then change to zero
     m=Uint(Error)
     \\ Hex is Print Hexadecimal for unsigned numbers
     Hex m
     Print m=5605
     Print Error=0, ok=False
     
     Print Eval(DataMem, 0)=5605,  Eval(DataMem, 0)
     \\ sub used as Exit here
     Sub Ret()
           Return ExecMem, Address:=0xC3
           Address++
     End Sub
     Sub EmbByteByte()
           Return ExecMem, Address:=Number, Address+1:=Number, Address+2:=Number
           Address+=3
     End Sub
     Sub EmbByte()
           Return ExecMem, Address:=Number, Address+1:=Number
           Address+=2
     End Sub
     Sub EmbLong()
           Return ExecMem, Address:=Number, Address+1:=Number as Long
           Address+=5
     End Sub
     Sub EmbByteLong()
           Return ExecMem, Address:=Number, Address+1:=Number, Address+2:=Number as Long
           Address+=6
     End Sub

} CheckIt </lang>

Using a lambda function with closures two buffers (buffers are objects in M2000 to handle memory blocks). This also add 12 +7 as the task want (but with no pushing to stack, but poke to data buffer)

<lang M2000 Interpreter> Function MyAdd {

     Buffer DataMem as Long*2
     Buffer Code ExecMem as byte*32
     Address=0
     EmbByte(0x31, 0xC0)
     EmbByteLong(0x3,0x5, DataMem(0)) ' add eax, [DataMem(0)] 
     EmbByteLong(0x3,0x5, DataMem(1)) ' add eax, [DataMem(1)] 
     EmbLong(0xa3, DataMem(0)) ' mov [DataMem(0)], eax
     Rem :
     EmbByte(0x31, 0xC0) ' xor eax, eax 
     Ret() ' Return
     =lambda ExecMem, DataMem (a as double, b as double)-> {
           Return DataMem, 0:=a, 1:=b
           Try ok  {
                 Execute Code ExecMem, 0
           }
           If not ok then {
                 =Uint(Error)   
           }  Else {
                 =Eval(DataMem, 0)
           }
     }
     Sub Ret()
           Return ExecMem, Address:=0xC3
           Address++
     End Sub
     Sub EmbByte()
           Return ExecMem, Address:=Number, Address+1:=Number
           Address+=2
     End Sub
     Sub EmbLong()
           Return ExecMem, Address:=Number, Address+1:=Number as Long
           Address+=5
     End Sub
     Sub EmbByteLong()
           Return ExecMem, Address:=Number, Address+1:=Number, Address+2:=Number as Long
           Address+=6
     End Sub

} \\ Produce a lambda function with machine code inside UnsingedAdd=MyAdd() Print UnsingedAdd(12, 7), UnsingedAdd(500, 100) </lang>

Nim

Translation of: C

<lang nim>import posix

let MAP_ANONYMOUS {.importc: "MAP_ANONYMOUS", header: "<sys/mman.h>".}: cint

proc test(a, b: cint): cint =

 # mov EAX, [ESP+4]
 # add EAX, [ESP+8]
 # ret
 var code = [0x8B'u8, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0xC3]

 # create an executable buffer
 var buf = mmap(nil, sizeof(code), PROT_READ or PROT_WRITE or PROT_EXEC,
   MAP_PRIVATE or MAP_ANONYMOUS, -1, 0)

 # copy code to the buffer
 copyMem(buf, addr code[0], sizeof(code))
 # run code
 result = cast[proc(a, b: cint): cint {.nimcall.}](buf)(a, b)
 # free buffer
 discard munmap(buf, sizeof(code))

echo test(7, 12)</lang>

PARI/GP

GP can't peek and poke into memory, but PARI can add in those capabilities via C.

Translation of: C

<lang c>#include <stdio.h>

include <sys/mman.h>
include <string.h>
include <pari/pari.h>

int test(int a, int b) {

 char code[] = {0x8B, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0xC3};
 void *buf;
 int c;
 /* copy code to executable buffer */
 buf = mmap (0,sizeof(code),PROT_READ|PROT_WRITE|PROT_EXEC,
            MAP_PRIVATE|MAP_ANON,-1,0);

 memcpy (buf, code, sizeof(code));
 /* run code */
 c = ((int (*) (int, int))buf)(a, b);
 /* free buffer */
 munmap (buf, sizeof(code));
 return c;

}

void init_auto(void) {

 pari_printf("%d\n", test(7,12));
 return 0;

}</lang>

Pascal

Tested under Linux with Freepascal 2.6.4-32BIt ( like the Code used ) cdecl doesn't work in Freepascal under Linux 64-bit <lang pascal>Program Example66; {Inspired... program to demonstrate the MMap function. Freepascal docs } Uses

 BaseUnix,Unix;

const

 code : array[0..9] of byte = ($8B, $44, $24, $4, $3, $44, $24, $8, $C3, $00);
 a :longInt= 12; 
 b :longInt=  7;

type

 tDummyFunc = function(a,b:LongInt):LongInt;cdecl;

Var

   Len,k  : cint;
   P    : Pointer;

begin

 len := sizeof(code);
 P:= fpmmap(nil,
            len+1 ,
            PROT_READ OR PROT_WRITE OR PROT_EXEC,
            MAP_ANONYMOUS OR MAP_PRIVATE,
            -1, // for MAP_ANONYMOUS
            0);
 If P =  Pointer(-1) then
   Halt(4);

 for k := 0 to len-1 do
   pChar(p)[k] := char(code[k]);

 k := tDummyFunc(P)(a,b);

 Writeln(a,'+',b,' = ',k);
 if fpMUnMap(P,Len)<>0 Then
   Halt(fpgeterrno);

end.</lang>

output

12+7 = 19

Phix

Phix has a builtin assembler, which makes the specifics of this task "the hard way to do it".

atom mem = allocate(9)
poke(mem,{#8B,#44,#24,#04,#03,#44,#24,#08,#C3})
constant mfunc = define_c_func({},mem,{C_INT,C_INT},C_INT)
?c_func(mfunc,{12,7})
free(mem)

In Phix the #ilASM statement (which has guards to allow 32/64/WIN/LNX variants) is usually used for inline assembly, for example (but sticking to the task):

atom mem = allocate(9)
poke(mem,{#8B,#44,#24,#04,#03,#44,#24,#08,#C3})
integer res
#ilASM{ mov eax,[mem]
        call :%pLoadMint -- eax:=(int32)eax, in case mem>#3FFFFFFF
        push 12
        push 7
        call eax
        add esp,8
        mov [res],eax }
?res
free(mem)

Better yet, albeit perhaps deviating somewhat from the task, but adhering in spirit, and unlike the above runnable on both 32 and 64 bit:
(Were you to produce a list.asm from this, using p -d, it would show the x86 bytes above or the x64 equivalent, using a mix of octal and hex representations)

integer res
#ilASM{ jmp @f
      ::add
    [32]
        mov eax,[esp+4]
        add eax,[esp+8]
    [64]
        mov rax,[rsp+8]
        add rax,[rsp+16]
    []  
        ret
      @@:
        push 12
        push 7
        call :add
    [32]
        add esp,8
        mov [res],eax
    [64]
        add rsp,16
        mov [res],rax
    []
      }
?res

In practice I would omit the jmp/labels/call/ret and probably just use registers instead of the stack:

integer res
#ilASM{
    [32]
        mov eax,12
        mov edx,7
        add eax,edx
        mov [res],eax
    [64]
        mov rax,12
        mov rdx,7
        add rax,rdx
        mov [res],rax
    []
      }
?res

All four cases output 19

PicoLisp

The following runs on 64-bit PicoLisp. Therefore we need some glue code to interface to the task's 32-bit code. <lang PicoLisp>(setq P

  (struct (native "@" "malloc" 'N 39) 'N
     # Align
     144                  # nop
     144                  # nop

     # Prepare stack
     106 12               # pushq $12
     184 7 0 0 0          # mov $7, %eax
     72 193 224 32        # shl $32, %rax
     80                   # pushq %rax

     # Rosetta task code
     139 68 36 4 3 68 36 8

     # Get result
     76 137 227           # mov %r12, %rbx
     137 195              # mov %eax, %ebx
     72 193 227 4         # shl $4, %rbx
     128 203 2            # orb $2, %bl

     # Clean up stack
     72 131 196 16        # add $16, %rsp

     # Return 
     195 )                # ret
  foo (>> 4 P) )

Execute

(println (foo))

Free memory

(native "@" "free" NIL P)</lang> Output:

PL/M

This code runs on an 8080 (or Z80) processor.

PL/M does not assume the existence of any operating system features or come with a standard library, so communicating with the OS actually has to be done in the same manner as calling (any other) machine language routines.

<lang plm>100H:

/* 8080 MACHINE CODE TO ADD TWO BYTES:

  79       MOV A,C     ; LOAD FIRST ARG INTO ACCUMULATOR
  83       ADD E       ; ADD SECOND ARG TO ACCUMULATOR
  C9       RET         ; RETURN */

DECLARE ADD$8080 DATA (79H, 83H, 0C9H);

/* THE 8080 PL/M CALLING CONVENTION IS THAT THE

  NEXT-TO-LAST ARG IS PUT IN (B)C, THE LAST ARG IN (D)E.
  (THE REST ARE IN MEMORY BUT WE DO NOT NEED ANY MORE.)
  THE RETURN ARGUMENT SHOULD BE IN THE ACCUMULATOR.
  WE CAN DEFINE A WRAPPER PROCEDURE TO DECLARE THE
  TYPES OF THE ARGUMENTS. */

EXEC$ADD: PROCEDURE (A,B) BYTE;

   DECLARE (A,B) BYTE;
   /* WE CAN 'GO TO' CONSTANTS OR VARIABLES, BUT NOT TO
      EXPRESSIONS. SO WE HAVE TO FETCH THE ADDRESS FIRST. */ 
   DECLARE LOC ADDRESS;
   LOC = .ADD$8080;
   GO TO LOC;

END EXEC$ADD;

/* IN FACT, PL/M DOES NOT COME WITH ANY STANDARD LIBARIES.

  IT IS FROM BEFORE THE TIME THAT YOU COULD ASSUME THERE
  WOULD EVEN BE AN OPERATING SYSTEM, THOUGH CP/M
  (THE PREDECESSOR TO DOS) WOULD QUICKLY BECOME STANDARD.
   
  WE NEED TO USE THIS EXACT TRICK TO GET CP/M TO PRINT THE
  RESULT TO THE OUTPUT. LUCKILY (AND NOT COINCIDENTALLY), 
  THE CP/M SYSCALL ENTRY POINT IS COMPATIBLE WITH THE
  PL/M CALLING CONVENTION. */

BDOS: PROCEDURE (FUNC, ARG);

   DECLARE FUNC BYTE;
   DECLARE ARG ADDRESS;
   /* 5 IS THE CP/M BDOS ENTRY POINT */
   GO TO 5;

END BDOS;

/* WE ALSO NEED OUR OWN NUMBER OUTPUT ROUTINE. WE CAN WRITE

  IT IN PL/M, THEN USE THE ABOVE ROUTINE TO TELL CP/M
  TO PRINT THE RESULT. */

PRINT$NUMBER: PROCEDURE(N);

   DECLARE S (4) BYTE INITIAL ('...$');
   DECLARE P ADDRESS;
   DECLARE (N, C BASED P) BYTE;
 
   /* EXTRACT EACH DIGIT AND WRITE THEM BACKWARDS TO A STRING */
   P = .S(3);

DIGIT:

   P = P-1;
   C = (N MOD 10) + '0';
   N = N/10;
   IF N > 0 THEN GO TO DIGIT;

   /* TELL CP/M TO PRINT THE RESULTING STRING */
   CALL BDOS(9, P);

END PRINT$NUMBER;

/* USING OUR OWN MACHINE CODE WORKS IN THE SAME WAY */ CALL PRINT$NUMBER( EXEC$ADD( 7, 12) ); /* THIS PRINTS 19 */

CALL BDOS(0,0); /* EXIT */ EOF</lang>

Output:

PureBasic

Using the Windows API:

<lang PureBasic>CompilerIf #PB_Compiler_Processor <> #PB_Processor_x86

 CompilerError "Code requires a 32-bit processor."

CompilerEndIf

Machine code using the Windows API

Procedure MachineCodeVirtualAlloc(a,b)

vm = VirtualAlloc_(#Null,?ecode-?scode,#MEM_COMMIT,#PAGE_EXECUTE_READWRITE)

   If(*vm)
       CopyMemory(?scode, *vm, ?ecode-?scode)
       eax_result=CallFunctionFast(*vm,a,b)
       VirtualFree_(*vm,0,#MEM_RELEASE)
       ProcedureReturn eax_result
   EndIf

EndProcedure

rv=MachineCodeVirtualAlloc( 7, 12) MessageRequester("MachineCodeVirtualAlloc",Str(rv)+Space(50),#PB_MessageRequester_Ok)

HEAP_CREATE_ENABLE_EXECUTE=$00040000

Procedure MachineCodeHeapCreate(a,b) hHeap=HeapCreate_(#HEAP_CREATE_ENABLE_EXECUTE,?ecode-?scode,?ecode-?scode)

   If(hHeap)
       CopyMemory(?scode, hHeap, ?ecode-?scode)
       eax_result=CallFunctionFast(hHeap,a,b)
       HeapDestroy_(hHeap)
       ProcedureReturn eax_result
   EndIf

EndProcedure

rv=MachineCodeHeapCreate(7,12) MessageRequester("MachineCodeHeapCreate",Str(rv)+Space(50),#PB_MessageRequester_Ok) End

8B442404 mov eax,[esp+4]
03442408 add eax,[esp+8]
C20800 ret 8

DataSection scode: Data.a $8B,$44,$24,$04,$03,$44,$24,$08,$C2,$08,$00 ecode: EndDataSection</lang>

Python

Works with: CPython version 3.x

The ctypes module is meant for calling existing native code from Python, but you can get it to execute your own bytes with some tricks. The bulk of the code is spent establishing an executable memory area - once that's done, the actual execution takes just a few lines.

<lang Python>import ctypes import os from ctypes import c_ubyte, c_int

code = bytes([0x8b, 0x44, 0x24, 0x04, 0x03, 0x44, 0x24, 0x08, 0xc3])

code_size = len(code)

copy code into an executable buffer

if (os.name == 'posix'):

   import mmap
   executable_map = mmap.mmap(-1, code_size, mmap.MAP_PRIVATE | mmap.MAP_ANON, mmap.PROT_READ | mmap.PROT_WRITE | mmap.PROT_EXEC)
   # we must keep a reference to executable_map until the call, to avoid freeing the mapped memory
   executable_map.write(code)
   # the mmap object won't tell us the actual address of the mapping, but we can fish it out by allocating
   # some ctypes object over its buffer, then asking the address of that
   func_address = ctypes.addressof(c_ubyte.from_buffer(executable_map))

elif (os.name == 'nt'):

   # the mmap module doesn't support protection flags on Windows, so execute VirtualAlloc instead
   code_buffer = ctypes.create_string_buffer(code)
   PAGE_EXECUTE_READWRITE = 0x40  # Windows constants that would usually come from header files
   MEM_COMMIT = 0x1000
   executable_buffer_address = ctypes.windll.kernel32.VirtualAlloc(0, code_size, MEM_COMMIT, PAGE_EXECUTE_READWRITE)
   if (executable_buffer_address == 0):
       print('Warning: Failed to enable code execution, call will likely cause a protection fault.')
       func_address = ctypes.addressof(code_buffer)
   else:
       ctypes.memmove(executable_buffer_address, code_buffer, code_size)
       func_address = executable_buffer_address

else:

   # for other platforms, we just hope DEP isn't enabled
   code_buffer = ctypes.create_string_buffer(code)
   func_address = ctypes.addressof(code_buffer)

prototype = ctypes.CFUNCTYPE(c_int, c_ubyte, c_ubyte) # build a function prototype from return type and argument types func = prototype(func_address) # build an actual function from the prototype by specifying the address res = func(7,12) print(res) </lang>

Racket

<lang racket>#lang racket/base

(require ffi/unsafe)

set up access to racket internals

(define scheme-malloc-code

 (get-ffi-obj 'scheme_malloc_code #f (_fun (len : _intptr) -> _pointer)))

(define scheme-free-code

 (get-ffi-obj 'scheme_free_code #f (_fun _pointer -> _void)))

(define opcodes '(139 68 36 4 3 68 36 8 195))

(define code (scheme-malloc-code 64))

(for ([byte opcodes]

     [i (in-naturals)])
 (ptr-set! code _ubyte i byte))

(define function (cast code _pointer (_fun _ubyte _ubyte -> _ubyte)))

(function 7 12)

(scheme-free-code code)</lang>

Raku

I don't know how to translate this C line <lang C>c = ((int (*) (int, int))buf)(a, b);</lang> so cannot solve the task with an idiomatic solution. I have also tried with Go's approach by adding a helper program but it also doesn't work out. Nonetheless I just present the attempt here so perhaps someone can fix that in 10 seconds. <lang perl6>use NativeCall;

constant PROT_READ = 0x1; # constant PROT_WRITE = 0x2; # constant PROT_EXEC = 0x4; # from local /usr/include/bits/mman.h constant MAP_PRIVATE = 0x02; # constant MAP_ANON = 0x20; #

sub mmap(Pointer $addr, size_t $length, int32 $prot, int32 $flags,

  int32 $fd, size_t $offset --> Pointer) is native { * };

sub memcpy(Pointer $dest, Pointer $src, size_t $size --> Pointer) is native {*} sub munmap(Pointer $addr, size_t $length) is native { * };

sub test (uint8 $a, uint8 $b) {

  my $code = CArray[uint8].new(
     0x90, 0x90, 0x6A, 0xC, 0xB8, 0x7, 0x0, 0x0, 0x0, 0x48, 0xC1, 0xE0, 0x20,
     0x50, 0x8B, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0x4C, 0x89, 0xE3, 0x89,
     0xC3, 0x48, 0xC1, 0xE3, 0x4, 0x80, 0xCB, 0x2, 0x48, 0x83, 0xC4, 0x10, 0xC3   
  );
  my $buf =
     mmap(Pointer, nativesizeof($code), PROT_READ +| PROT_WRITE +| PROT_EXEC,
     MAP_PRIVATE +| MAP_ANON, -1, 0);

  memcpy($buf, nativecast(Pointer,$code), nativesizeof($code));

  my $c; # = ((int (*) (int, int))buf)(a, b);

  munmap($buf, nativesizeof($code));

  return $c = "Incomplete Attempt";

}

say test 7, 12;</lang>

In the mean time, here is a less desirable approach by writing a wrapper for the C entry, with the 64 bit instructions from PicoLisp ..

Translation of: C

test.c

<lang C>#include <stdio.h>

include <stdlib.h>
include <sys/mman.h>
include <string.h>

int test (int a, int b) {

 char code[] = {
    0x90, 0x90, 0x6A, 0xC, 0xB8, 0x7, 0x0, 0x0, 0x0, 0x48, 0xC1, 0xE0, 0x20,
    0x50, 0x8B, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0x4C, 0x89, 0xE3, 0x89,
    0xC3, 0x48, 0xC1, 0xE3, 0x4, 0x80, 0xCB, 0x2, 0x48, 0x83, 0xC4, 0x10, 0xC3
 };

 void *buf;
 int c;
 /* copy code to executable buffer */
 buf = mmap (0,sizeof(code),PROT_READ|PROT_WRITE|PROT_EXEC,
            MAP_PRIVATE|MAP_ANON,-1,0);
 memcpy (buf, code, sizeof(code));
 /* run code */
 c = ((int (*) (int, int))buf)(a, b);
 /* free buffer */
 munmap (buf, sizeof(code));
 return c;

}</lang> mcode.raku <lang perl6>#!/usr/bin/env raku

20200501 Raku programming solution

use NativeCall;

constant LIBTEST = '/home/user/LibTest.so';

sub test(uint8 $a, uint8 $b) returns uint8 is native(LIBTEST) { * };

say test 7, 12; </lang>

Output:

gcc -Wall -fPIC -shared -o LibTest.so test.c

file LibTest.so LibTest.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=90d2695df9a56b88a57144147fb9288ac07b172f, not stripped ./mcode.raku

19

Rust

This is heavily inspired by https://www.jonathanturner.org/2015/12/building-a-simple-jit-in-rust.html
Hence, only working on Linux (the only other way to disable memory execution protection on other OSes was to use other crates, which kind of defeats the purpose.) <lang Rust>extern crate libc;

[cfg(all(

   target_os = "linux",
   any(target_pointer_width = "32", target_pointer_width = "64")

))] fn main() {

   use std::mem;
   use std::ptr;

   let page_size: usize = 4096;
   let (bytes, size): (Vec<u8>, usize) = if cfg!(target_pointer_width = "32") {
       (
           vec![0x8b, 0x44, 0x24, 0x04, 0x03, 0x44, 0x24, 0x08, 0xc3],
           9,
       )
   } else {
       (vec![0x48, 0x89, 0xf8, 0x48, 0x01, 0xf0, 0xc3], 7)
   };
   let f: fn(u8, u8) -> u8 = unsafe {
       let mut page: *mut libc::c_void = ptr::null_mut();
       libc::posix_memalign(&mut page, page_size, size);
       libc::mprotect(
           page,
           size,
           libc::PROT_EXEC | libc::PROT_READ | libc::PROT_WRITE,
       );
       let contents: *mut u8 = page as *mut u8;
       ptr::copy(bytes.as_ptr(), contents, 9);
       mem::transmute(contents)
   };

   let return_value = f(7, 12);
   println!("Returned value: {}", return_value);
   assert_eq!(return_value, 19);

}

[cfg(any(

   not(target_os = "linux"),
   not(any(target_pointer_width = "32", target_pointer_width = "64"))

))] fn main() {

   println!("Not supported on this platform.");

} </lang>

Scala

This example is incomplete. The text below cannot be considered a contribution that specifically addresses the task, it is rather a subjective judgement. Please either contribute code or remove and place in the talk section of this page. Regards. Please ensure that it meets all task requirements and remove this message.

PEEK, POKE and inserting machine opcode makes your system vulnerable which is not quite professional.

Considered to be more harmful than useful.

Smalltalk

I agree that this is more harmful than useful. The only target audience are compiler writers and Smalltalk-core developers (of which I guess are not too many around).

Also, this is highly cpu specific, the task is for an x86 and also assuming a particular calling convention; both is probably (definitely) not the case (most, incl. myself are on 64bit machines these days).

Anyway, as a sketch, here is how to do it (I won't waste time in making an x86_64 version for the particular calling convention used on my machine; and yes: it is even different between Unix and Windows systems!):

First we need a way to allocate executable memory (btw. we should probably also care to flush any instruction caches, which I won't go into here); This is very Smalltalk dialect specific, and probably not supported on other Smalltalks; in ST/X, where inline C-code can be compiled dynamically, we can define it as:

Works with: Smalltalk/X

<lang smalltalk>!ExternalBytes class methods!

mapExecutableBytes:size %{

include <sys/mman.h>

   void *mem;
   OBJ retVal;
   int nBytes = __intVal(size);

   mem = mmap(nil, nBytes, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
   if (mem != MAP_FAILED) {
       RETURN( __MKEXTERNALBYTES_N(mem, nBytes));
   }

%}.

   self primitiveFailed

! !</lang>

next, we need the correct code; the following presents the x86 version (but do not expect this code to NOT crash the Smalltalk VM, as the calling convention is certainly wrong..) <lang smalltalk>OperatingSystem getCPUType = #'x86' ifTrue:[

   code := #[0x8B 0x44 0x24 0x04 0x03 0x44 0x24 0x08 0xC3].

] ifFalse:[

   self error:'unsupported cpu'

].

handle := ExternalBytes mapExecutableBytes:100. handle replaceFrom:1 with:code.

" dump it (debugging only)... " e'code at {handle address hexPrintString} is:' printCR. (handle copyFrom:1 to:50) asByteArray hexPrintString printCR.

" create an ExternalFunction for it " func := ExternalLibraryFunction new code:handle address. func name:'unnamed' module:nil returnType:#int argumentTypes:#(int int). func beCallTypeC. func printCR.

" now call it " result := func invokeWithArguments:{10 . 20} </lang> With a few more tricks, it is even possible to install that function as a method in a class; but additional code needs to be generated, to assert that the passed data is correctly boxed/unboxed.

Swift

Translation of: C

Using 64-bit glue code since Swift has limited 32-bit support on x86.

<lang swift>import Foundation

typealias TwoIntsOneInt = @convention(c) (Int, Int) -> Int

let code = [

 144, // Align
 144,
 106, 12, // Prepare stack
 184, 7, 0, 0, 0,
 72, 193, 224, 32,
 80,
 139, 68, 36, 4, 3, 68, 36, 8, // Rosetta task code
 76, 137, 227, // Get result
 137, 195,
 72, 193, 227, 4,
 128, 203, 2,
 72, 131, 196, 16, // Clean up stack
 195, // Return

] as [UInt8]

func fudge(x: Int, y: Int) -> Int {

 let buf = mmap(nil, code.count, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0)

 memcpy(buf, code, code.count)

 let fun = unsafeBitCast(buf, to: TwoIntsOneInt.self)
 let ret = fun(x, y)

 munmap(buf, code.count)

 return ret

}

print(fudge(x: 7, y: 12)) </lang>

Tcl

Translation of: C

Library: Critcl

<lang tcl>package require critcl

critcl::ccode {

   #include <sys/mman.h>

}

Define a command using C. The C is embedded in Tcl, and will be
built into a shared library at runtime. Note that Tcl does not
provide a native way of doing this sort of thing; this thunk is
mandatory.

critcl::cproc runMachineCode {Tcl_Obj* codeObj int a int b} int {

   int size, result;
   unsigned char *code = Tcl_GetByteArrayFromObj(codeObj, &size);
   void *buf;

   /* copy code to executable buffer */
   buf = mmap(0, (size_t) size, PROT_READ|PROT_WRITE|PROT_EXEC,
           MAP_PRIVATE|MAP_ANON, -1, 0); 
   memcpy(buf, code, (size_t) size);
   /* run code */
   result = ((int (*) (int, int)) buf)(a, b);
   /* dispose buffer */
   munmap(buf, (size_t) size);

   return result;

}

But now we have our thunk, we can execute arbitrary binary blobs

set code [binary format c* {0x8B 0x44 0x24 0x4 0x3 0x44 0x24 0x8 0xC3}] puts [runMachineCode $code 7 12]</lang> Note that it would be more common to put that thunk in its own package (e.g., machineCodeThunk) and then just do something like this: <lang tcl>package require machineCodeThunk 1.0

set code [binary format c* {0x8B 0x44 0x24 0x4 0x3 0x44 0x24 0x8 0xC3}] puts [runMachineCode $code 7 12]</lang>

Wren

Translation of: C

Wren is a high-level scripting language and cannot execute machine code directly.

However, it is designed for embedding and we can therefore ask the host to do this for us. Here, we use a host program written in C, the language which Wren itself is written in. <lang ecmascript>/* machine_code.wren */

class C {

   // pass the machine code in string form to the host
   foreign static runMachineCode(s, a, b)

}

var a = 7 var b = 12

// x64 opcodes for this task var m = [

   0x55, 0x48, 0x89, 0xe5, 0x89, 0x7d,
   0xfc, 0x89, 0x75, 0xf8, 0x8b, 0x75,
   0xfc, 0x03, 0x75, 0xf8, 0x89, 0x75,
   0xf4, 0x8b, 0x45, 0xf4, 0x5d, 0xc3

]

var s = m.map { |byte| String.fromByte(byte) }.join() System.print("%(a) + %(b) = %(C.runMachineCode(s, a, b))")</lang>
We now embed this Wren script in the following C program, compile and run it. <lang c>#include <stdlib.h>

include <stdio.h>
include <string.h>
include <sys/mman.h>
include "wren.h"

unsigned char rmc_helper(const char *code, unsigned char a, unsigned char b, int l) {

   void *buf;
   unsigned char c;

   /* copy code to executable buffer */
   buf = mmap (0, l, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
   memcpy(buf, code, l);

   /* run code */
   c = ((unsigned char (*) (unsigned char, unsigned char))buf)(a, b);

   /* free buffer */
   munmap(buf, l);

   /* return result to caller */
   return c;

}

void C_runMachineCode(WrenVM* vm) {

   /* unpack arguments passed from Wren */
   int *len;
   const char *code = wrenGetSlotBytes(vm, 1, len);
   unsigned char a = (unsigned char)wrenGetSlotDouble(vm, 2);
   unsigned char b = (unsigned char)wrenGetSlotDouble(vm, 3);

   /* obtain result */
   unsigned char c = rmc_helper(code, a, b, *len);

   /* return result to Wren */
   wrenSetSlotDouble(vm, 0, (double)c);

}

WrenForeignMethodFn bindForeignMethod(

   WrenVM* vm,
   const char* module,
   const char* className,
   bool isStatic,
   const char* signature) {
   if (strcmp(module, "main") == 0) {
       if (strcmp(className, "C") == 0) {
           if (isStatic && strcmp(signature, "runMachineCode(_,_,_)") == 0) {
               return C_runMachineCode;
           }
       }
   }
   return NULL;

}

static void writeFn(WrenVM* vm, const char* text) {

   printf("%s", text);

}

void errorFn(WrenVM* vm, WrenErrorType errorType, const char* module, const int line, const char* msg) {

   switch (errorType) {
       case WREN_ERROR_COMPILE:
           printf("[%s line %d] [Error] %s\n", module, line, msg);
           break;
       case WREN_ERROR_STACK_TRACE:
           printf("[%s line %d] in %s\n", module, line, msg);
           break;
       case WREN_ERROR_RUNTIME:
           printf("[Runtime Error] %s\n", msg);
           break;
   }

}

char *readFile(const char *fileName) {

   FILE *f = fopen(fileName, "r");
   fseek(f, 0, SEEK_END);
   long fsize = ftell(f);
   rewind(f);
   char *script = malloc(fsize + 1);
   fread(script, 1, fsize, f);
   fclose(f);
   script[fsize] = 0;
   return script;

}

int main() {

   WrenConfiguration config;
   wrenInitConfiguration(&config);
   config.writeFn = &writeFn;
   config.errorFn = &errorFn;
   config.bindForeignMethodFn = &bindForeignMethod;
   WrenVM* vm = wrenNewVM(&config);
   const char* module = "main";
   const char* fileName = "machine_code.wren";
   char *script = readFile(fileName);
   WrenInterpretResult result = wrenInterpret(vm, module, script);
   switch (result) {
       case WREN_RESULT_COMPILE_ERROR:
           printf("Compile Error!\n");
           break;
       case WREN_RESULT_RUNTIME_ERROR:
           printf("Runtime Error!\n");
           break;
       case WREN_RESULT_SUCCESS:
           break;
   }
   wrenFreeVM(vm);
   free(script);
   return 0;

}</lang>

Output:

7 + 12 = 19

X86-64 Assembly

UASM 2.52

Linux Build


$ uasm -elf64 mexec.asm
$ gcc -o mexec mexec.o -no-pie
With MUSL libc
$ musl-gcc -o mexec mexec.o -e main -nostartfiles -no-pie

Windows Build
$ uasm64 -win64 mexec.asm
$ link /machine: x64 /subsystem:console /release websrv.obj
kernel32.lib msvcrt.lib

option casemap:none option literals:on

WIN64 equ 1 LIN64 equ 3

ifndef __MEMEXEC_CLASS__ __MEMEXEC_CLASS__ equ 1

 if @Platform eq WIN64 
   option dllimport:<kernel32>
     HeapAlloc       proto fd:qword, flgs:dword, hlen:qword 
     HeapFree        proto fd:qword, flgs:dword, lpmem:qword 
     GetProcessHeap  proto 
     ExitProcess     proto uexit:word 
   option dllimport:<msvcrt>
     printf      proto fmt:qword, args:VARARG
     memcpy      proto d:qword, s:qword, mlen:qword 
   option dllimport:none 
     exit equ ExitProcess 
 elseif @Platform eq LIN64 
   malloc        proto SYSTEMV len:qword
   free          proto SYSTEMV m:qword 
   printf        proto SYSTEMV fmt:qword, args:VARARG
   mprotect      proto SYSTEMV m:qword, s:qword, flgs:dword
   memcpy        proto SYSTEMV d:qword, s:qword, mlen:qword 
   exit          proto SYSTEMV uexit:word     
   
   PROT_READ     equ 01h
   PROT_WRITE    equ 02h
   PROT_EXEC     equ 04h
   PROT_NONE     equ 00h
   PROT_ALL      equ PROT_READ + PROT_WRITE + PROT_EXEC
 endif

 CLASS memexec 
   CMETHOD run 
 ENDMETHODS 
   buff    db 048h, 089h, 0F8h         ;; mov rax, rdi
           db 048h, 001h, 0F0h         ;; add rax, rsi
           db 0C3h                     ;; ret
   mem     dq ?                        ;; Memory address
   mlen    dq 0                        ;; Memory size allocated?
 ENDCLASS

 pmemexec typedef ptr memexec

 METHOD memexec, Init, <VOIDARG>, <uses rcx>
   local tmp:qword

   mov rbx, thisPtr
   assume rbx:ptr memexec
   lea rdx, [rbx].buff 
   invoke printf, CSTR("[mexec->Init] - bytecode addr: 0x%X",10), rdx 
   mov tmp, rdx
   mov [rbx].mlen, sizeof(tmp)
   invoke printf, CSTR("[mexec->Init] - bytecode len: %i",10), [rbx].mlen 
   ;; In Built memory allocator, used by the Class extention 
   ;; Uses either HeapAlloc for windows or malloc for everything else. 
   ;; Which is why I didn't use mmap in the first place.
   MEMALLOC([rbx].mlen) 
   .if rax == -1
     invoke printf, CSTR("[exec->Init->Error] - Malloc failed with -1",10)
     mov rax, rbx 
     ret
   .endif
   mov [rbx].mem, rax 
   invoke printf, CSTR("[mexec->Init] - [rbx].mem addr: 0x%X",10), [rbx].mem 
   ;; Memory wont be executable by default from Malloc, So we make it
   ;; so with mprotect. Not sure about windows, Might need to use a VirtualProtect
   ;; call..
   if @Platform eq LIN64
     invoke mprotect, [rbx].mem, [rbx].mlen, PROT_ALL
     .if rax == -1
       invoke printf, CSTR("[exec]-Init->Error] - mprotect failed with -1",10)
       mov rax, rbx 
       ret 
     .endif
   endif
   invoke printf, CSTR("[mexec->Init] Copying [rbx].buff bytecode to 0x%X",10), [rbx].mem 
   invoke memcpy, [rbx].mem, addr [rbx].buff, [rbx].mlen 
   .if rax == -1
     invoke printf, CSTR("[mexec->Init->Error] - memcpy failed with -l",10)
     mov rax, rbx 
     ret 
   .endif 
   mov rcx, [rbx].mem
   mov rax, rbx 
   assume rbx:nothing
   ret
 ENDMETHOD

 METHOD memexec, run, <VOIDARG>, <>, arg1:qword, arg2:qword
   mov rbx, thisPtr 
   assume rbx:ptr memexec 
   mov rdi, arg1
   mov rsi, arg2 
   call [rbx].mem
   assume rbx:nothing
   ret 
 ENDMETHOD

 METHOD memexec, Destroy, <VOIDARG>, <>
   mov rbx, thisPtr 
   assume rbx:ptr memexec 
   mov [rbx].mlen, 0
   MEMFREE([rbx].mem)
   assume rbx:nothing 
   ret 
 ENDMETHOD

endif ;; __MEMEXEC_CLASS__ .data a1 dq 7 a2 dq 12

.code main proc

 local pmem:ptr memexec 
 
 mov pmem, _NEW(memexec)
 pmem->run(a1,a2)
 invoke printf, CSTR("[pmem->run(%i, %i)] - returned: %i",10), a1, a2, rax 
 _DELETE(pmem)
 invoke exit, 0
 ret

main endp

end </lang>