Multi-line macros as operands

[mattsains]

I wrote a small bit of assembly for nasm like this:

Code: [Select]

%macro register 1
    %if %1 = 0
        rax
    %elif %1 = 1
        rbx
    %elif %1 = 2
        rcx
    %endif
%endmacro
   
add register(1), register(2)
   
I expect that to evaluate to 'add rbx, rcx'

However, nasm -E test.asm returns this, showing that the macro is not evaluated:

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%line 10+1 test.asm

add register(1), register(2)

Compare that to this code:

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%macro register 1
    %if %1 = 0
        rax
    %elif %1 = 1
        rbx
    %elif %1 = 2
        rcx
    %endif
%endmacro
   
register(1)

which is transformed into

Code: [Select]

%line 10+1 test.asm

rbx

Why the difference? How can I achieve what I expect in the first snippet?