Question

I tried to simulate IF() …. ELIF …. ENDIF in assembly for PIC16F84, but it doesn’t seem to work for more than one usage. I tried to use something like this in two places, but it gives some error that a label is duplicated. Shouldn’t the parameter from the macro be replaced in the labels too? (name in true_name:)

_f macro name
  btfsc EQUAL,0
  goto true_name
  goto false_name
  true_name:
endm

_lse macro name
  goto next_name
  false_name:
endm

_ndif macro name
  goto next_name
  next_name:
endm

;; usage example
_f label1
  ...
_lse label1
  ...
_ndif 

Answer 1

I kinda solved this problem with MPLAB variables, here’s an example for testing equality between a register and a literal:

_f_equal_literal macro register,literal,name
    movlw literal
    subwf register,0
    btfss STATUS,2 ;bit indicating result is zero
    goto _false#v(name)
    endm

_lse macro name
    goto _next#v(name)
_false#v(name):
    endm

_ndif macro name
_next#v(name):
    endm

Notice that I didn’t use goto _true#v(name) and _true#v(name): label, you’ll just have to figure if you need btfss or btfsc.

You can have a single _lse and _ndif macro, and have multiple macros for _f statements.

GJ’s solution doesn’t have a next label, so the true branch will execute the false branch.

---

You need to define a variable for each if-else-endif construct.
It might even useful if the variable name describes what the if-else-endif is used for.

Example:

variable testing_something=123

_f_equal_literal some_register,some_value,testing_something
                ...       

_lse testing_something
                ...        

_ndif testing_something