woz64/libs/timers.asm

#importonce
#import "../core/module.asm"


// ========================================================
// ////// MACROS //////////////////////////////////////////
// ========================================================

.filenamespace Timers

* = * "Timers Lib"

// ========================================================
// ////// METHODS /////////////////////////////////////////
// ========================================================


// --------------------------------------------------------
// init -
// Module Init.
// --------------------------------------------------------
init: {
                rts
}

// --------------------------------------------------------
// toDebug -
// Print debug info.
// --------------------------------------------------------
toDebug: {
                ModuleToDebug(module_type, module_name, version)
                rts
}

// --------------------------------------------------------
// multiply -
// 8 Bit in to 16 Bit out Multiplier
//
// Parameters:
//      MemMap.MATH.factor1       = 8 Bit Factor 1
//      MemMap.MATH.factor2       = 8 Bit Factor 2
//
// Result
//      MemMap.MATH.result        = 16 bit result
// --------------------------------------------------------
delayOne: {
                pha
                lda     #$00
                sta     MemMap.TIMERS.counter
    loop1:      lda     #$fb    // wait for vertical retrace
    loop2:      cmp     $d012   // until it reaches 251th raster line ($fb)
                bne     loop2       // which is out of the inner screen area
                inc     MemMap.TIMERS.counter // increase frame counter
                lda     MemMap.TIMERS.counter // check if counter
                cmp     #$32    // reached 50
                bne     out         // if not, pass the color changing routine
                jmp     exit

    out:
                lda     $d012   // make sure we reached
    loop3:      cmp     $d012   // the next raster line so next time we
                beq     loop3
                jmp loop1 // jump to main loop
    exit:
                pla
                rts
}


// ========================================================
// ////// DATA ////////////////////////////////////////////
// ========================================================

* = * "Timers Lib Data"
module_type:    .byte Module.TYPES.LIB
version:        .byte 1, 0, 0

.encoding "screencode_mixed"
module_name:
                .text "timers"
                .byte 0


#import "../hardware/mem_map.asm"