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; -----------------------------------------------
; --- extern declared SFRs
; -----------------------------------------------
extern _STATUS
extern _FSR
extern _INDF
extern _PCLATH
extern _PCL
C EQU 0
DC EQU 1
Z EQU 2
IRP EQU 7
; -----------------------------------------------
; --- generic pointer access helpers
; -----------------------------------------------
GPTRTAG_DATA EQU 0x00
GPTRTAG_CODE EQU 0x80
; setup FSR to point to (STK00:STK01)
setup_fsr macro
movf STK01, W
movwf _FSR
; select indirectly addressed bank
bcf _STATUS, IRP
btfsc STK00, 0
bsf _STATUS, IRP
endm
; increment FSR, update IRP on bank crossings
; FIXME: update IRP if FSR is reset to 0...
inc_fsr macro
incf _FSR, F
endm
; dispatch according to gptr type
select_routine macro dataptr, codeptr
; __data pointer tag: 0x00
xorlw GPTRTAG_DATA
btfsc _STATUS, Z
goto dataptr
; __code pointer tag: 0x80
xorlw (GPTRTAG_DATA ^ GPTRTAG_CODE)
btfsc _STATUS, Z
goto codeptr
endm
check_data macro dataptr
; __data pointer tag: 0x00
xorlw GPTRTAG_DATA
btfsc _STATUS, Z
goto dataptr
endm
|
