Create a procedure named `CreateRandomString` that generates a random string with a length of 20, consisting of only uppercase letters. When invoking the `CreateRandomString` procedure, pass the length `L` in the `EAX` register, and provide a pointer to a byte array that will store the random string. Write a test program within the `main` procedure that calls `CreateRandomString` ten times and outputs the generated strings to the console window.

The task requires creating a procedure in assembly language, which is often system-specific. I'll provide you a general template that you would have to adapt depending on the specific assembly language you are using (e.g., x86, ARM, etc.). This example will assume an x86 architecture and NASM assembler for illustration purposes.

Here is a typical assembly language procedure for generating a random string and a test program to call it:

```asm section .bss ; Reserve 21 bytes for the random string (20 characters + null terminator) randomString resb 21

section .data alphabet db "ABCDEFGHIJKLMNOPQRSTUVWXYZ" alphabetSize equ $-alphabet ; The size of the alphabet

section .text global _start

; Random generator initialization (this part might depend on the system) RandomInit: ; Get the current timestamp as seed mov eax, 0 call time ; Seed the random number generator mov edi, eax ret

; The 'CreateRandomString' procedure CreateRandomString: pushad ; Save all general purpose registers mov ecx, EAX ; 'EAX' contains the length 'L' mov edi, [esp + 36] ; Pointer to the byte array to store random string

generate_loop: ; Generate a random value between 0 and 'alphabetSize' - 1 call RandomNumber ; Convert random number to an uppercase letter add al, 'A' sub al, (alphabetSize / 2) ; Adjust if random number range differs ; Store the letter in the string mov [edi], al ; Move to the next character inc edi ; Decrement the loop counter loop generate_loop

; Null-terminate the string mov byte [edi], 0 popad ; Restore all general purpose registers ret

; Random number generation function (pseudo-random for this example) RandomNumber: ; Here you would have actual random generation code. ; For simplicity, let's assume it is already provided and works correctly ; Normally you would use a system call/library function or a custom algorithm ret

; The '_start' main procedure _start: call RandomInit ; Initialize random number generator

mov ecx, 10 ; Loop counter for 10 strings print_loop: mov eax, 20 ; Pass the length 'L' in the 'EAX' register lea edi, [randomString] ; Pass the pointer to the byte array call CreateRandomString ; Call our procedure

; Output the generated string - system-dependent (might use sys_write) ; Here you would put OS-specific code to print the string (assuming nasm/linux for example) ; mov eax, 4 ; mov ebx, 1 ; mov ecx, edi ; mov edx, 20 ; int 0x80 ; or syscall for 64-bit

; Loop for the next string loop print_loop

; Exit program (OS-specific, NASM/Linux example) ; mov eax, 1 ; xor ebx, ebx ; int 0x80 ; or syscall for 64-bit ``` Remember, this is pseudocode and may require system-specific modifications. Also, generating random numbers in assembly often involves system calls or using a random generator library since assembly itself doesn't have built-in functions like high-level languages.

Extra: 1. Pseudorandom number generation: In this example, `RandomNumber` is a placeholder for a function that generates a random number. Usually, random numbers in a computer are not truly random but instead pseudorandom, generated by algorithms that simulate randomness.

2. `pushad` and `popad`: These instructions push all general-purpose registers onto the stack and pop them back, respectively. They're used here to preserve registers across procedure calls.

3. Looping: The `loop` instruction decrements the `ECX` register and jumps to the target label if `ECX` is not zero.

4. Pointers: The `EDI` register is used as a pointer to the memory location where the random string is stored. The `LEA` (load effective address) instruction is used to load the address of `randomString` into `EDI`.

5. System calls: To output data to the console or perform certain actions, system calls are used. They are low-level OS service requests. The example contains commented-out code that may be used on a Linux system with NASM to output strings to the console.

Please adapt the code according to the rules of the assembler and the system you are using.