ASM6502 does not support structures. What can I do?

[boeckmann]

For offset calculation, you can fake them by misusing .ORG in connection with local labels. Example:

MY_SAVED_PC = @

my_structure:   .org 0
  @field_a      .org @+2  ; word-sized element
  @field_b      .org @+1  ; byte-sized element
  @size

another_struct: .org 0
  @x   .org @+4
  @y   .org @+4
  @size

.org MY_SAVED_PC

The lines containing MY_SAVED_PC are not nessessary if the "structures" are defined at the beginning of the file and before the first .ORG directive belonging to your program.

If you want to reserve space for such a "structure" and initialize it with zero you may use fill:

my_var .fill my_struct@size

If you want to access elements of the data structure you can use:

lda my_var + my_struct@field_a