4.33 Idata_acs Directive

The MPASM IDATA_ACS directive creates a section for PIC18 access bank objects that must be initialised.

Suggested Replacement

Use any of the PIC Assembler's directives that can reserve space in a suitable data memory psect, and collate the initial values in a separate psect placed in program memory.

The following PIC18 example reserves the runtime memory for the variables in the Access Bank and places the initial values for these variables in program memory. Assembler-provided psects were used in this example, but you can define you own suitable psects, if required.

#include <xc.inc>
;define space for the variables in RAM
PSECT udata_acs
vars:
input:
  DS 2
output:
  DS 1

;place the initial values for the above in a matching order in program memory
PSECT data
iValues:
  DW 55AAh
  DB 67h

Your application will need to provide code that copies the initial values to the reserved data memory space, as shown in the following example which copies the values at iValues to vars.

PSECT text,class=CODE
copy0:
  movlw   low (iValues)
  movwf   tblptrl
  movlw   high(iValues)
  movwf   tblptrh
  movlw   low highword(iValues)
  movwf   tblptru
  tblrd*+
  movff   tablat, vars+0
  tblrd*+
  movff   tablat, vars+1
  tblrd*+
  movff   tablat, vars+2
  return

When copying larger amounts of data, consider using a loop and FSR register to indirectly write to the variables in data memory.