Version of the arduino MILLIS function (OshonSoft Basic).

public function millis() as longword
    dim t_intcon as byte
    const GIE = 7

    // get current intr enable state and disable intrs
    // while we access the global msec variable
    t_intcon = INTCON
    INTCON.bits(GIE) = 0

    // read global variable to get return value
    result = tmr_ms

    // restore intr state
    if (t_intcon.bits(GIE) = 1) then
        INTCON.bits(GIE) = 1
    endif
end function

'***********************************************************************
'MILLIS function III, long type geneal counter.
'For replacing absolute pauses generated with WaitMs.
'The _MILLIS() function increments every mSec. so it takes
'approximately 49.7 days To reinitialize.
'That is, it will pass through a zero value.
'************************************************************************
'Pic16F88, OshonSoft Pic Basic Compiler v8.42
'By COS, 03/2023, PCB PicEBasic.
'************************************************************************
#define CONFIG = 0x2f50  'Fuse definition.
#define CONFIG2 = 0x3ffc
Define CLOCK_FREQUENCY = 8  'Clock a 8Mhz
'Define SIMULATION_WAITMS_VALUE = 1'Waitms is used activate for simulation.
Include "_FuncionesPic16F88.bas"
'************************************************************************
main:
    'Clock internal 8Mhz.
    Call _setup_oscillator_mode_select_bit(_oscillator_mode_defined_by_fosc)
    Call _setup_oscillator(_osc_8mhz)
    'PCB configuration
    AllDigital
    TRISA = 0x00  'Puerto A como salidas
    TRISB = 0x00  'Puerto B como salidas
    TRISA.4 = 1  'Input (RA4, adc)
    TRISA.6 = 1  'Input (RA6, tecla S1)
    TRISA.5 = 1  'Input (RA5, tecla S2)
    TRISB.5 = 0  'Output (RB5,Tx RS232)
    TRISB.2 = 1  'Input (RB2, Rx RS232)
    TRISB.4 = 1  'Input (RHT03)
    TRISB.0 = 0  'Output (LedGreen)
    TRISA.7 = 0  'Output (LedYellow)
    TRISB.3 = 0  'Output (Backlight)
    'Configuration LCD 2x16 ports. ---------------------------------------
    Define LCD_BITS = 4  'Data bus length to 4bits
    Define LCD_DREG = PORTA  'Data bus: puerto A
    Define LCD_DBIT = 0  'Least significant bit of the data bus.
    Define LCD_RSREG = PORTB  'Rs control bit on port B
    Define LCD_RSBIT = 7  'RS bit on RB7 pin.
    Define LCD_EREG = PORTB  'E control bit on port B.
    Define LCD_EBIT = 6  'E pin on RB6 pin
    Define LCD_COMMANDUS = 2000  'Wait after each command in uSec.
    Define LCD_DATAUS = 100  'Wait after sending a data to the LCD in uSec.
    Define LCD_INITMS = 50  'Wait during display initialization in mSec.
    '---------------------------------------------------------------------
    Lcdinit  'Lcd withou cursor
    'Initialize Timer1 desborde 1mSec.
    Call _setup_timer1(_tmr1_internal, _tmr1_div1)
    Call _set_timer1(0xf831)  'Interruption every 1uSec.
    Call _timer1(_on)
    Call _enable_interrupts(_int_timer1)
    'Assign names to the Leds
    Symbol LedGreen = RB0
    Symbol LedYellow = RA7
    Symbol Backlight = RB3
    Backlight = 1
    '********************************************************************
    Dim PreMillis As Long
    Dim PreMillis1 As Long
 
    Lcdout "Ready"
    Call _SetUp_MILLIS()  'Initializes _MILLIS
    Call _enable_interrupts(_global)

    While True  'Infinite Loop
   
        Call _MILLIS()  'Update _MILLIS
   
        'Yellow led flashing
        If (_MILLIS - PreMillis) >= 500 Then  'If time passes (mSec.)
            PreMillis = _MILLIS  'The last value of _MILLIS is stored.
            Toggle LedYellow  'Invers the state of the led.
        Endif
   
        'Green led flashing
        If (_MILLIS - PreMILLIS1) >= 1000 Then  'If time passes (mSec.)
            PreMillis1 = _MILLIS  'The last value of _MILLIS is stored.
            Toggle LedGreen  'Invers the state of the led.
        Endif
   
    Wend
End                                          
'**************************************************
'**************************************************
'Function _MILLIS v. III
'Requires the use of a timer and interrupts.
'By COS, 02/2023, PIC Basic Compiler v8.38
'**************************************************
'Call _SetUp_MILLIS()  'Before triggering interrupts
'Call _MILLIS()  'Update _MILLIS And Return the value of the Millis counter
'Call _CounterMillis()  'Incrementa contador Millis
'**************************************************
'Group of new functions for _MILLIS
'Inicialize functions
Proc _SetUp_MILLIS()
    _MILLIS = 0
    _CounterMillis = 0
End Proc                                    
'Return _MILLIS as Long and global variable
Function _MILLIS() As Long
    Disable  'Stop interruption
    _MILLIS = _CounterMillis
    Enable  'Enable interruption
End Function                                
'Increment the counter Millis
'Return _Counter_Millis as Long and global variable
Function _CounterMillis() As Long
    _CounterMillis++
End Function                                
'**************************************************
'Interrupt vector
On Interrupt  'Disable interruption
    Save System
    If _tmr1if Then
        Call _set_timer1(0xf831)  'Reload TMR1 registers to count 1mSec and clear _Tmr1If.
        Call _CounterMillis()  'Increments counter Millis every mSec.
    Endif
Resume  'Enable interruption

#define CONFIG = 0x2f50 'Fuse definition.
#define CONFIG2 = 0x3ffc
Define CLOCK_FREQUENCY = 8 'Clock a 8Mhz

Dim intFlag as bit
Dim ms as long

main:
    OSCCON=%01110000            '8MHz = 2,000,000 instructions per second
    'setup 1mS interrupt = 2,000,000/4 = 500,000/10 = 50,000 set PR2=49 = 50,000/50 = 1000 = 1mS
    '                          4=prescaler    10=postscaler 
    T2CON = %01001101
    PR2 = 49
    PIR1.TMR2IE = 1              'timer 2 interrupts enable
    PEIE=1
    GIE=1
    while(1)
    wend
End

function getMillis() as long
    intFlag=false
    getMillis=ms
    if intFlag then             'if an interrupt has happened then reread the value
        getMillis=ms            'another interrupt can't happen until a full milli second has passed
    endif
End Function

On Interrupt
Save System
    intFlag=true
    if PIR2.TMR2IF then
        ms=ms+1
        PIR2.TMR2IF=0
    Endif
Resume

#define CONFIG2 = 0x3ffc
Define CLOCK_FREQUENCY = 8  'Clock a 8Mhz
'Define SIMULATION_WAITMS_VALUE = 1'Waitms is used activate for simulation.
Include "_FuncionesPic16F88.bas"
Include "_FuncionesTmrBase.bas"
Include "_FuncionMillis.bas"
'************************************************************************
main:
    'Pin configuration
    AllDigital
    ConfigPin PORTA = Output
    ConfigPin PORTB = Output
    'Configuration lcd ports. -------------------------------------
    Define LCD_BITS = 4  'Data bus length to 4bits
    Define LCD_DREG = PORTA  'Data bus: puerto A
    Define LCD_DBIT = 0  'Least significant bit of the data bus.
    Define LCD_RSREG = PORTB  'Rs control bit on port B
    Define LCD_RSBIT = 7  'RS bit on RB7 pin.
    Define LCD_EREG = PORTB  'E control bit on port B.
    Define LCD_EBIT = 6  'E pin on RB6 pin
    Define LCD_COMMANDUS = 2000  'Wait after each command in uSec.
    Define LCD_DATAUS = 100  'Wait after sending a data to the LCD in uSec.
    Define LCD_INITMS = 50  'Wait during display initialization in mSec.
    '---------------------------------------------------------------------
    'Clock internal 8Mhz.
    Call _setup_oscillator_mode_select_bit(_oscillator_mode_defined_by_fosc)
    Call _setup_oscillator(_osc_8mhz)

    Lcdinit  'Lcd withou cursor
    Lcdout "Ready"

    'Initialize timer2 desborde 1mSec.
    Call _setup_timer2(_tmr2_div16, 0x82, 1)
    Call _timer2(_on)
    Call _enable_interrupts(_int_timer2)

    'Assign names to the Leds
    Symbol LedGreen = RB0
    Symbol LedYellow = RA7
    '********************************************************************
    Dim PreMillis As Long
    Dim PreMillis1 As Long
    Dim PreMillis2 As Long
    Dim Counter As Long
    PreMillis = 0
    PreMillis1 = 0
    PreMillis2 = 0
    Counter = 0
    Call _setup_millis()  'Setup _MILLIS functions, before activate interrupts
    'Call _bt0call(_btsetup, 200)  'Wait time in mSec.
    'Call _bt1call(_btsetup, 1)  'Wait time in mSec.
    'Call _bt2call(_btsetup, 1000)  'Wait time in mSec.
    Call _enable_interrupts(_global)
    
    'Loop
    While True

        Call _millis()  'Repeat As few times As possible, so As Not To interfere with interruptions.

        'If _bt0if = True Then
        If (_millis - PreMillis) >= 200 Then  'Wait time in mSec.
            PreMillis = _millis  'The last value of _MILLIS is stored.
            'Call _bt0call(_btsetup, 100)  'Wait time in mSec.
            Toggle LedYellow  'Invers the state of the led.
        Endif

        'If _bt1if = True Then
        If (_millis - PreMillis1) >= 1 Then  'Wait time in mSec.
            PreMillis1 = _millis  'The last value of _MILLIS is stored.
            'Call _bt1call(_btsetup, 10)  'Wait time in mSec.
            Toggle LedGreen  'Invers the state of the led.
        Endif

        Counter++
        
        If (_millis - PreMillis2) >= 1000 Then
        'If _bt2if = True Then
            Lcdcmdout LcdLine2Home
            Lcdout "Counter:", #Counter
            While True
            Wend
        Endif

    Wend
End                                               
'********************************************************************
'********************************************************************
'Interrupt vector
On Interrupt  'Disable interruptions
Save System
    If _tmr2if Then
        _tmr2if = 0
        Call _countermillis()  'Increments _CounterMILLIS every mSec.
        'Call _bt0call(_btupdated, _null)  'Counter Long type
        'Call _bt1call(_btupdated, _null)  'Counter Word type
        'Call _bt2call(_btupdated, _null)  'Counter Word type
        
    Endif
Resume  'Enable interruptions

#define CONFIG = 0x2f50 'Fuse definition.
#define CONFIG2 = 0x3ffc
Define CLOCK_FREQUENCY = 8 'Clock a 8Mhz

Dim ms as long

main:
    OSCCON=%01110000            '8MHz = 2,000,000 instructions per second
    'setup 1mS interrupt = 2,000,000/4 = 500,000/10 = 50,000 set PR2=49 = 50,000/50 = 1000 = 1mS
    '                          4=prescaler    10=postscaler
    T2CON = %01001101
    PR2 = 49
    PIE1.TMR2IE = 1              'timer 2 interrupts enable
    PEIE=1
    GIE=1
    while(1)
    wend
End

function getMillis() as long
    getMillis=ms
    if getMillis.LB<>ms.LB then 'an interrupt must have happened so fetch it again
        getMillis=ms            'another interrupt can't happen until a full milli second has passed
    endif
End Function

On Interrupt
Save System
      ms=ms+1
      PIR1.TMR2IF=0
Resume