main.asm

#include "syscall.h"
#include "constants.h"

.data
.align 1

    goodResponse:       .asciz "HTTP/1.1 200 OK\r\n\r\n"
    badResponse:        .asciz "HTTP/1.1 404 File not found\r\n\r\n"
    delimiterString:    .asciz "\r\n\r\n"
    malformedReq:       .asciz "The Request is malformed"
    GET:                .asciz "GET"
    POST:               .asciz "POST"
    
    sockfd:             .word 0x0
    currfd:             .word 0x0

    addr:               .half 	AF_INET     # AF_INET 
                        .half 	5000        # sin_port
                        .byte 	127,0,0,1   # sin_addr
                        .word 	0x0         # sin_zero
                        .word 	0x0

    goodResponseLen:    .word badResponse       - goodResponse  -1 
    badResponseLen:     .word delimiterString   - badResponse   -1
    malformedReqLen:    .word GET               - malformedReq  -1
    addrLen:            .word goodResponseLen   - addr


.bss
    buffer:             .space BUFFER_SIZE
    currBufferLen:      .space 4
    reqMethod:          .space 4 # 0 means GET,1 means POST
    reqURI:             .space MAX_FILENAME_LEN+1
    reqFD:              .space 4


.text
.globl __start
__start:

    socket:
        li $a0,AF_INET
        li $a1,SOCK_STREAM
        li $a2,IPPROTO_IP

        li $v0,SYS_socket
        syscall

        la $t5,sockfd
        sw $v0,0($t5)

    bind:
        lw $a0,sockfd
        la $a1,addr
        lw $a2,addrLen

        li $v0, SYS_bind
        syscall


    listen:
        lw $a0,sockfd
        li $a1,NULL

        li $v0,SYS_listen
        syscall


    requestLoop:
        accept:
            lw $a0,sockfd
            li $a1,NULL
            li $a2,NULL

            li $v0,SYS_accept
            syscall

            la $t5,currfd
            sw $v0,0($t5)

        move $s0,$v0
        la $s1, buffer
        li $s4, 0x0 # counter

        readLoop:
            move $a0,$s0
            add $a1,$s1,$s4
            li $a2, 1

            li $v0, SYS_read
            syscall

            add $a1,$s1,$s4
            lb 	$t1,0($a1)
            li 	$t3,' '

            addiu $s4,$s4,1
            bne $t1, $t3, readLoop

    slti $t5,$s4,6
    beq $t5,$0,methodNotValid

    move $a0,$s0
    move $a1,$s1
    li $a2, 20
    
    li $v0,SYS_write
    syscall

    close:
        lw $a0,currfd
        li $v0,SYS_close
        syscall

    j requestLoop

    li $a0,0
    li $v0,SYS_exit
    syscall


.globl methodNotValid
methodNotValid:
    
    lw $a0,currfd
    la $a1,malformedReq
    lw $a2,malformedReqLen

    li $v0, SYS_write
    syscall

    jr $ra