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woz64/libs/timers.asm
2020-03-08 22:57:30 -07:00

87 lines
2.5 KiB
NASM

#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"