Right now I'd be happy getting a clean compile in MPLAB-X for a 16F877 on a LAB X-1 board. I pulled this code from one of my old folders, I assume something is no longer supported, or I forgot to include some library or some such (I added the blockchain using that youtube video).

Code:
ADCON1 = 7              ' A/D off, all digital
ASM
@ DEVICE PIC16F877, HS_OSC, WDT_OFF, PWRT_ON, BOD_ON, LVP_OFF, CPD_OFF, WRT_OFF, DEBUG_OFF, PROTECT_OFF
ENDASM

DEFINE  OSC     20


LED7    VAR     PortD.7
LED6    VAR     PortD.6
LED5    VAR     PortD.5
LED4    VAR     PortD.4
LED3    VAR     PortD.3
LED2    VAR     PortD.2
LED1    VAR     PortD.1
LED0    VAR     PortD.0

        TRISD.7 = 0
        TRISD.6 = 0
        TRISD.5 = 0
        TRISD.4 = 0
        TRISD.3 = 0
        TRISD.2 = 0
        TRISD.1 = 0
        TRISD.0 = 0

        LOW LED7
        LOW LED6
        LOW LED5
        LOW LED4
        LOW LED3
        LOW LED2
        LOW LED1
        LOW LED0

START:  HIGH    LED7
        PAUSE   500
        LOW     LED7
        HIGH    LED6
        PAUSE   500
        LOW     LED6
        HIGH    LED5
        PAUSE   500
        LOW     LED5
        HIGH    LED4
        PAUSE   500
        LOW     LED4
        HIGH    LED3
        PAUSE   500
        LOW     LED3
        HIGH    LED2
        PAUSE   500
        LOW     LED2
        HIGH    LED1
        PAUSE   500
        LOW     LED1
        HIGH    LED0
        PAUSE   500
        LOW     LED0
        GOTO    START
Finish: end
I'm guessing that ASM statement is probably no longer good; got some reading to do. MPLAB-X error messages remind me of IBM manuals.