I had the problem with the procedure:

Print PROC
    ARG pStr:WORD
    mov si, pStr
PrintLoop:
    lodsb
    cmp al, 0   ; End of line?
    je  PrintRet
    int 29h     ; Print AL byte
    jmp PrintLoop
PrintRet:
    ret
Print   endp

Calling code:

push offset FileName
call Print

Result: it does not work as expected.

I have found some info about ARG directive:

Article #19021: TP 5.0/TASM - ARG DIRECTIVE SYMBOLIC REFERENCES

 Technical Notes Database

TN4021C.txt   TP 5.0/TASM  - ARG DIRECTIVE SYMBOLIC REFERENCES
Category   : Pascal
Platform    : All
Product    : TD  1.x 2.0

Description:
Q. I am using the Arg directive to create symbolic references to
   variables on the stack.  I am not getting the correct values
   I should in the Assembler routine.  What am I doing wrong?
A. It is easier if remember a few points about the Arg directive.
   First, the Arg directive always adjusts for a near or far
   call.  If you have a proc definition like:
          myproc proc far
   the Arg directive will take into account the four (4) byte return
   address on the stack.  If your definition looks like:
          myproc proc near
   the Arg directive will adjust for a two (2) byte return
   address on the stack.  The second thing to remember is that
   the Arg directive always assumes that you will push BP onto
   the stack first and thus, will add two bytes to the size of
   the return address.  For a far return the total will be six
   bytes and for a near return the total will be four bytes.  The
   third point to remember about the Arg directive itself is that
   the leftmost symbol in the Arg list will be nearest the top of
   the stack.  Finally, remember that for each subsequent symbol
   to the right, a number equal to the number of bytes on the
   stack occupied by the symbols to the left will be added to the
   BP register.
   Consider the following examples:
          myproc proc near
          arg first:word, second:word
          push bp
          mov  bp,sp
   The distance is near, a two byte return address, and the BP is
   assumed to pushed onto the stack.  Thus, any reference to
   first is equivalent to [BP + 04H].  Since first is a word it
   occupies two bytes on the stack.  Thus second evaluates to [BP
   + 04H + 02H] or [BP + 06H].
          myproc proc far
          arg first:word, second:word
          push bp
          mov  bp,sp
   The distance is far, a four byte return address, and the BP is
   assumed to be pushed onto the stack.  Thus, any reference to
   first if equivalent to [BP + 06H].  Since first is a word, it
   occupies two bytes on the stack.  Thus, second evaluates to
   [BP + 06H + 02H] or [BP + 08H].
          myproc proc far
          arg first:near ptr word, second:word
          push bp
          mov  bp,sp
   The distance is far, a four byte return address, and the BP is
   assumed to be pushed onto the stack.  Thus any reference to
   first is equivalent to [BP + 06H].  Since first is a near
   pointer it occupies two bytes on the stack.  Thus second
   evaluates to [BP + 06H + 02H] or [BP + 08H].
          myproc proc far
          arg first:byte, second:word
          push bp
          mov  bp,sp
   The distance is far, a four byte return address, and the BP is
   assumed to be pushed onto the stack.  Thus, any reference to
   first is equivalent to [BP + 06H].  Although first is a byte
   value it occupies two bytes on the stack.  Thus, second
   evaluates to [BP + 06H + 02H] or [BP + 08H].
          myproc proc far
          arg first:byte:1, second:word
          push bp
          mov  bp,sp
   The distance is far, a four byte return address, and the BP is
   assumed to be pushed onto the stack.  Thus, any reference to
   first is equivalent to [BP + 06H].  Although first is a byte
   value it occupies two bytes on the stack.  To force it to use
   only one byte we must use the :1 after the word byte.  Second
   evaluates to {BP + 06H + 01H] or [BP + 07H].  Note that the
   type of variables must match the types of those that appear in
   the high level language call.

Reference:

7/2/98 10:45:32 AM

Last Modified: 01-SEP-99

Source note: Article #19021: TP 5.0/TASM - ARG DIRECTIVE SYMBOLIC REFERENCES

Print PROC
    ARG pStr:WORD
    push bp          ; ADDED
    mov  bp, sp      ; ADDED
    mov si, pStr
PrintLoop:
    lodsb
    cmp al, 0   ; End of line?
    je  PrintRet
    int 29h     ; Print AL byte
    jmp PrintLoop
PrintRet:
    pop bp           ; ADDED
    ret
Print   endp

Tags: tasm