我正在用mpsam迁移在mplab中开发的一个旧程序，但我找不到方法来解决在新的mplab X IDE v4.0中用pic生成错误的两行代码。附件是迁移后的代码，指出它在哪里生成错误。
#include <xc.inc>
CONFIG FOSC = HS
CONFIG WDTE = OFF
CONFIG PWRTE = ON
CONFIG BOREN = OFF
CONFIG LVP = OFF
CONFIG CPD = OFF
CONFIG WRT = OFF
CONFIG CP = OFF
ORG 0x00
GOTO INICIO
ms_20:
clrf TMR0
;The following line gives me an error
movlw .80
xorwf TMR0,w
;The following line gives me an error
bnz $-3
return
INICIO:
bsf STATUS, 5
bcf STATUS, 6
movlw 00000000B
movwf TRISB
movlw 00000111B
movwf OPTION_REG
bcf STATUS, 5
bcf STATUS, 6
clrf PORTB
bsf PORTB,0
call ms_20
bcf PORTB,0
call ms_20
goto m0
m0:
bsf PORTB,0
call ms_20
bcf PORTB,0
call ms_20
goto m0
END
旧版本中的原始代码如下：
LIST P=16F877A
INCLUDE<P16F877A.INC>
_CONFIG 0x3F31
ORG 0x00
goto INICIO
ms_20 clrf TMR0
movlw .80
xorwf TMR0,w
bnz $-3
return
INICIO bsf STATUS, 5
bcf STATUS, 6
movlw B'00000000'
movwf TRISB
movlw B'00000111'
movwf OPTION_REG
bcf STATUS, RP0
bcf STATUS, RP1
clrf PORTB
bsf PORTB,0
call ms_20
bcf PORTB,0
call ms_20
goto m0
m0 bsf PORTB,0
call ms_20
bcf PORTB,0
call ms_20
goto m0
END
将汇编代码从MPASM移植到pic作为汇编程序有很多问题。
以下是作为汇编程序移植到pic的代码示例：
;
; File: main.S
; Target: PIC16F877A
; Author: dan1138
; Date: 2020-10-09
; Compiler: pic-as(v2.40)
; IDE: MPLABX v6.00
;
; Description:
;
; Example for https://stackoverflow.com/questions/73941514/what-do-i-need-to-correct-in-the-creation-of-delay-routine-using-tmr0-on-the-pic
;
; Add this line in the project properties box, pic-as Global Options -> Additional options:
; -Wa,-a -Wl,-pPor_Vec=0h,-pIsr_Vec=4h
;
PROCESSOR 16F877A
PAGEWIDTH 132
RADIX DEC
;
#include <xc.inc>
; PIC16F877A Configuration Bit Settings
; 'C' source line config statements
; CONFIG
config FOSC = HS ; Oscillator Selection bits (HS oscillator)
config WDTE = OFF ; Watchdog Timer Enable bit (WDT disabled)
config PWRTE = OFF ; Power-up Timer Enable bit (PWRT disabled)
config BOREN = OFF ; Brown-out Reset Enable bit (BOR disabled)
config LVP = OFF ; Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3 is digital I/O, HV on MCLR must be used for programming)
config CPD = OFF ; Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
config WRT = OFF ; Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
config CP = OFF ; Flash Program Memory Code Protection bit (Code protection off)
;
; Skip macros
;
skipnc MACRO
btfsc STATUS,STATUS_C_POSITION
ENDM
skipc MACRO
btfss STATUS,STATUS_C_POSITION
ENDM
skipnz MACRO
btfsc STATUS,STATUS_Z_POSITION
ENDM
skipz MACRO
btfss STATUS,STATUS_Z_POSITION
ENDM
;
; Branch macros
;
bnz MACRO arg
btfss STATUS,STATUS_Z_POSITION
goto arg
ENDM
bz MACRO arg
btfsc STATUS,STATUS_Z_POSITION
goto arg
ENDM
bnc MACRO arg
btfss STATUS,STATUS_C_POSITION
goto arg
ENDM
bc MACRO arg
btfsc STATUS,STATUS_C_POSITION
goto arg
ENDM
;
; Power-On-Reset entry point
;
PSECT Por_Vec,global,class=CODE,delta=2
global resetVec
resetVec:
PAGESEL INICIO
goto INICIO
;
; Data space use by interrupt handler to save context
PSECT Isr_Data,global,class=COMMON,space=1,delta=1,noexec
;
GLOBAL WREG_save,STATUS_save,PCLATH_save
;
WREG_save: DS 1
STATUS_save: DS 1
PCLATH_save: DS 1
;
; Interrupt vector and handler
PSECT Isr_Vec,global,class=CODE,delta=2
GLOBAL IsrVec
;
IsrVec:
movwf WREG_save
swapf STATUS,W
movwf STATUS_save
movf PCLATH,W
movwf PCLATH_save
;
IsrHandler:
;
IsrExit:
movf PCLATH_save,W
movwf PCLATH
swapf STATUS_save,W
movwf STATUS
swapf WREG_save,F
swapf WREG_save,W
retfie ; Return from interrupt
;
; Section used for main code
PSECT MainCode,global,class=CODE,delta=2
ms_20:
clrf TMR0
movlw 80
xorwf TMR0,w
bnz $-3
return
INICIO: bsf STATUS,STATUS_RP0_POSITION
bcf STATUS,STATUS_RP1_POSITION
movlw 0b00000000
movwf TRISB
movlw 0b00000111
movwf OPTION_REG
bcf STATUS,STATUS_RP0_POSITION
bcf STATUS,STATUS_RP1_POSITION
clrf PORTB
bsf PORTB,0
call ms_20
bcf PORTB,0
call ms_20
goto m0
m0: bsf PORTB,0
call ms_20
bcf PORTB,0
call ms_20
goto m0
;
; Declare Power-On-Reset entry point
;
END resetVec
这取决于你去做研究，去理解发生了什么变化以及为什么。