读取十六进制并将其转换为十进制

Question

我需要编写一个MIPS汇编语言程序来从文件中读取十六进制值（每行一个）。应该请求文件名并从控制台读取文件名。读取号码后，将其转换为内部存储器。输入格式可以是固定格式，32位，二进制补码值或可变长度的有符号幅度。转换后，该值应打印到控制台。

到目前为止我所拥有的：

.data
    fileName: .space 100
    prompt1: .asciiz "Enter the file name: "
    buffer: .space 40966
.text
    main:
    # prompt user for file name
        li $v0, 4           #system call for printing string
        la $a0, prompt1         #load prompt1
        syscall             #print string

    # when entering name of the file, add its entire directory path with double backslashes
        li $v0, 8           #system call for reading string
        la $a0, fileName        #load user input into the address of fileName
        li $a1, 50          # max number of characters the fileName can hold
        syscall             #store user input into fileName


    # converting the string into a null-terminated string
    # replacing last character of fileName with 0 instead of \n

            la   $s0, fileName          # $s0 contains fileName
        add   $s2, $0, $0           # $s2 = 0 (null terminator)
        addi   $s3, $0, '\n'        # $s3 = '\n' (newline escape sequence)

    removeNL:
        lb   $s1, 0($s0)        # load character into $s0
        beq   $s1, $s3, replaceNL       # Break if byte is equal to newline *
        addi   $s2, $s2, 1          # increment counter otherwise
        addi   $s0, $s0, 1          # increment string address
        j   removeNL
    replaceNL:
        sb   $0, 0($s0)         #replace newline with null terminator

    # Open file for reading now that input file name is converted to null-terminated string
        li $v0, 13          # system call for open file
        la $a0, fileName        # address of null-terminated string containing filename
        li $a1, 0           # flags
        li $a2, 0           # mode
        syscall             # open a file
        move $s0, $v0           # save the file descriptor

    # reading from file just opened

        li $v0, 14          # system call for reading from file
        move $a0, $s0           # file descriptor
        la $a1, buffer          # address of input buffer
        li $a2, 40966           # maximum number of char