Dear PIC enthusiasts,

I just stumbled across this snippet of code
for (16 bit instruction set) 17c PICs.

<pre>
;***************************************************************
;* Macro   LONGC           ;Long Call    ;by Walter Quitt
; for 17c PICs
; http://piclist.org/techref/microchip/17inst.htm
;***************************************************************
LONGC MACRO SUBROUTINE
   bsf     CPUSTA,GLINTD       ;interrupts off
   movlw   HIGH (SUBROUTINE)
   movfp   WREG,PCLATH         ;Z unaffected
   bcf     CPUSTA,GLINTD       ;interrupts on
   lcall   LOW  (SUBROUTINE) ; (a single instruction on the 17c7xx, not the 3
instruction macro on 14 bit cores).
   ENDM
</pre>

Um... I fail to see the point. Is there ever any reason to use that rather than
this shorter, faster, less interrupt-latency-inducing code:

<pre>
;***************************************************************
;* Macro   LONGC           ;Long Call    ;originally by Walter Quitt
; for 17c PICs ; 2001-06-16:DAV: removed extraneous (?) instructions
; http://piclist.org/techref/microchip/17inst.htm
;***************************************************************
LONGC MACRO SUBROUTINE
   movlw   HIGH (SUBROUTINE)
   movwf   PCLATH         ;Z unaffected
   lcall   LOW  (SUBROUTINE) ; (a single instruction on the 17c7xx, not the 3
instruction macro on 14 bit cores).
   ENDM
</pre>
?

Am I overlooking something obvious in
  the datasheet
  http://www.microchip.com/0/lit/pline/picmicro/
or
  the errata
  http://www.microchip.com/0/lit/suppdoc/errata/index.htm
?

--
David Cary

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