Passing parameters to execve call in assembly

gistfile1.txt

;Simple assembly execve call to execute /bin/ls -la 

global _start

section .text

_start:

        xor eax, eax            ;create null eax register
        push eax                ;push null eax register to the stack

        push 0x736c2f2f         ;push command to the stack
        push 0x6e69622f         ;"/bin//ls"
        mov ebx, esp            ;move pointer to command into ebx

        push eax                ;push null eax register to the stack
        push 0x61616c2d         ;push argument to the stack "-laa"
        mov esi, esp            ;move stack pointer to esi

        push eax                ;push null eax register to the stack
        push esi                ;push address of the argument to the stack
        push ebx                ;push address of the command to the stack
        mov ecx, esp            ;move pointer to start of the command to ecx


        mov al, 11              ;define execve
        int 0x80                ;execute command

Hi, great example, one of the few I've found working, but the parameter seems to be limited to just 4 bytes of the push instruction. How can the number of parameters or the length of a single parameter be increased?
For example "ls -la /usr" or "ls /home/myuser"!
Thank you for your answer.