Waitgroups in Assembly Language

; This is the function we'll run in every thread.
worker:
    push rbp
    mov rbp, rsp
    sub rsp, 16
    mov [rbp-8], rdi  ; Store worker ID

    ; Print "Worker X starting"
    mov rdi, fmt_start
    mov rsi, [rbp-8]
    xor eax, eax
    call printf

    ; Sleep to simulate an expensive task
    mov rdi, 1000000  ; 1 second in microseconds
    call usleep

    ; Print "Worker X done"
    mov rdi, fmt_done
    mov rsi, [rbp-8]
    xor eax, eax
    call printf

    leave
    ret

main:
    push rbp
    mov rbp, rsp
    sub rsp, 32

    ; Initialize counter
    mov dword [rbp-4], 0

    ; Launch several threads
    mov ecx, 5
create_thread:
    push rcx
    mov edi, worker
    mov esi, rcx
    call pthread_create
    pop rcx
    inc dword [rbp-4]
    loop create_thread

    ; Wait for all threads to finish
wait_threads:
    cmp dword [rbp-4], 0
    je done_waiting
    call pthread_join
    dec dword [rbp-4]
    jmp wait_threads

done_waiting:
    xor eax, eax
    leave
    ret

section .data
    fmt_start db "Worker %d starting", 10, 0
    fmt_done db "Worker %d done", 10, 0

section .text
    global main
    extern printf
    extern usleep
    extern pthread_create
    extern pthread_join

This Assembly Language code demonstrates a similar concept to the Go WaitGroups example, using POSIX threads (pthreads) for concurrency. Here’s an explanation of the code:

1. The worker function is defined, which simulates work by printing a start message, sleeping for a second, and then printing a done message.

2. In the main function, we create 5 threads using a loop and the pthread_create function. Each thread executes the worker function.

3. We keep track of the number of created threads using a counter stored at [rbp-4].

4. After creating the threads, we enter a loop to wait for all threads to finish using pthread_join.

5. The program exits once all threads have completed.

Note that this Assembly code is a simplified version and may need additional setup for proper execution, such as linking with the pthread library. The exact implementation details can vary depending on the specific assembler and operating system being used.

To run this program, you would typically need to:

1. Save the code in a file (e.g., waitgroups.asm)
2. Assemble it into an object file
3. Link it with the necessary libraries
4. Execute the resulting binary

The exact commands would depend on your system and the assembler you’re using. For example, using NASM on a Linux system, you might do:

$ nasm -f elf64 waitgroups.asm
$ ld -o waitgroups waitgroups.o -lc -lpthread
$ ./waitgroups

The output would be similar to the Go example, with workers starting and finishing in a potentially different order each time the program is run.

This Assembly implementation demonstrates low-level concurrency control, which is conceptually similar to the Go WaitGroups example, but with more explicit thread management.