NASM Macros: Multiple Local String Labels

[Laura (Gast)]

Hey there,
I am currently writing a call macro in NASM (elf64), which can be used 
like:

dcall FUNCTION, param1, param2, param3, ...

The parameters are handled differently, depending on their type. Numbers 
become immediates, strings need to be placed in the .data section, and 
are
then referenced by its address (label).

%macro dcall 1-*
%define _j %1
%assign __pnum 1
%assign __stck 0
%rep %0-1
  %ifstr %2
    section .data
    %%str: db %2, 0h
    section .text
    %if __pnum = 1
      mov rdi, %%str
    %elif __pnum = 2
      mov rsi, %%str
    %elif __pnum = 3
      mov rdx, %%str
    %elif __pnum = 4
      mov rcx, %%str
    %elif __pnum = 5
      mov r8, %%str
    %elif __pnum = 6
      mov r9, %%str
    %else
      push %%str
      %assign __stck __stck+8
    %endif
  %else
    %if __pnum = 1
      mov rdi, %2
    %elif __pnum = 2
      mov rsi, %2
    %elif __pnum = 3
      mov rdx, %2
    %elif __pnum = 4
      mov rcx, %2
    %elif __pnum = 5
      mov r8, %2
    %elif __pnum = 6
      mov r9, %2
    %else
      push %2
      %assign __stck __stck+8
    %endif
  %endif
  %assign __pnum __pnum+1
  %rotate 1
%endrep
  xor rax, rax
  call _j
  %if __stck != 0
    add rsp, __stck
  %endif
%endmacro

This works fine, unless there is more than one string parameter. In that 
case, the local %%str label is not unique any more. Does anyone know how 
to deal with this? Is there a way using macro contexts?