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|
; Test simulator program -*- asm -*-
$processor 84
$watchdog on
$pwrup on
$protect off
$clock rc, 400000
$idwords 1, 2, 3, 4
RTCC equ 1
Opt equ 1
Pcl equ 2
Status equ 3
Fsr equ 4
TrisA equ 5
PortA equ 5
TrisB equ 6
PortB equ 6
Intcon equ 0x0b
SP equ 0x0c
FP equ 0x0d
GR0 equ 0x0e
GR1 equ 0x0f
C equ 0 ; STATUS bit numbers
DC equ 1
Z equ 2
PD equ 3
TO equ 4
RP0 equ 5
RP1 equ 6
IRP equ 7
W equ 0
F equ 1
;;;
;;;----------------------------------------------------------------------
;;;
org 0
goto Entry
org 4
goto Interrupt
Entry: btfss Status,TO
goto WDTReset
btfss Status,PD
goto MCLRWakeup
PowerUp:movlw 0x30 ; Set up SP
movwf SP
movwf FP
bsf Status,RP0
clrw
movwf TrisA
movwf TrisB
movlw 0b11001000
movwf Opt
bcf Status,RP0
movlw 1
call push
movlw 2
call push
movlw 3
call push
movlw 4
call push
nop
call add16
nop
call pop
call pop
call pop
call pop
movlw 1
spin0: movwf PortA
clrwdt
spin1: rlf PortA,F
btfss PortA,4
goto spin1
clrf PortA
movwf PortB
spin2: rlf PortB,F
btfss PortB,7
goto spin2
clrf PortB
goto spin0
sleep
WDTReset:
goto WDTReset
MCLRWakeup:
goto MCLRWakeup
Interrupt:
goto Interrupt
add16: clrw
call fentry
movlw 4
call index
movf 0,W
movwf GR0
movlw 3
call index
movf 0,W
movwf GR1
movlw 2
call index
movf 0,W
addwf GR0,F
btfsc STATUS,C
incf GR1,F
movlw 1
call index
movf 0,W
addwf GR1,F
goto fexit
push: movwf GR0 ; *--SP = W
decf SP,F
movf SP,W
addlw -(GR1)
btfsc Status,Z
goto StackOverflow
movf SP,W
movwf Fsr
movf GR0,W
movwf 0
return
StackOverflow:
goto StackOverflow
pop: movf SP,W ; return *SP++
movwf Fsr
movf 0,W
incf SP,F
return
fentry: movwf GR1 ; push FP, FP = SP, SP -= W
movf FP,W ; This depends on push not using GR1!
call push
movf SP,W
movwf FP
_fent: movf GR1,F
btfsc Status,Z
return
call push
goto _fent
fexit: movf FP,W
movwf Fsr
movf 0,W
movwf FP
movf Fsr,W
movwf SP
incf SP,F
return
index: addwf FP,W ; Set Fsr to point to FP[W]
movwf Fsr
return
end
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