328 lines
21 KiB
Plaintext
328 lines
21 KiB
Plaintext
{{
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┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
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│ AYcog - AY-3-891X / YM2149 emulator V0.22 (C) 2010-05 Johannes Ahlebrand │
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├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
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│ TERMS OF USE: Parallax Object Exchange License │
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├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
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│Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation │
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│files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, │
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│modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software│
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│is furnished to do so, subject to the following conditions: │
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│ │
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│The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.│
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│ │
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│THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE │
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│WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR │
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│COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, │
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│ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
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└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
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}}
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CON
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PSG_FREQ = 2_000_000.0 ' Clock frequency input to the chip (Colour Genie EG2000 computer runs at 2.2Mhz)
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' WARNING !!
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' Don't alter the constants below unless you know what you are doing
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'-------------------------------------------------------------------
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SAMPLE_RATE = 125_000 ' Sample rate of AYcog
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OSC_CORR = trunc(1.05 * PSG_FREQ) ' Calibrates the relative oscillator frequency
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NOISE_CORR = OSC_CORR>>1 ' Calibrates the relative noise frequency
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ENV_CORR = OSC_CORR>>6 ' Calibrates the relative envelope timing
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'
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' Reg bits function
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' -----------------------------------
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' 00 7..0 channel A fine tune
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' 01 3..0 channel A coarse tune
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' 02 7..0 channel B fine tune
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' 03 3..0 channel B coarse tune
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' 04 7..0 channel C fine tune
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' 05 3..0 channel C coarse tune
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' 06 4..0 noise period
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' 07 7..0 enable register
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' 08 4..0 channel A volume
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' 09 4..0 channel B volume
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' 10 4..0 channel C volume
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' 11 7..0 envelope fine tune
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' 12 7..0 envelope coarse tune
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' 13 3..0 envelope shape
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' 14 7..0 I/O port A value
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' 15 7..0 I/O port B value
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VAR
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long cog
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PUB start(right,left,AYregisters)
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if (AYregisters & 1) <> 0 ' we need word aligned registers
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abort(-1)
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arg1 := $18000000 | left
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arg2 := $18000000 | right
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r1 := ((1<<right) | (1<<left))&!1
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sampleRate := clkfreq/SAMPLE_RATE
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cog := cognew(@AYEMU,AYregisters) + 1
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return cog
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PUB stop
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if cog
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cogstop(cog~ -1)
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dat org 0
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'
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' Assembly AY emulator
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'
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AYEMU mov AY_Address, par ' Setup everyting
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mov dira, r1
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mov ctra, arg1
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mov ctrb, arg2
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mov waitCounter, cnt
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add waitCounter, sampleRate
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'-----------------------------------------------------------
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mainLoop call #getRegisters
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call #AY ' Main loop
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call #mixer
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jmp #mainLoop
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'
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' Read all AY registers from hub memory and convert
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' them to more convenient representations.
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'
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getRegisters mov tempValue, AY_Address
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rdword frequency1, tempValue ' reg 0+1 Read in all 4
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shl frequency1, #20 ' frequency registers
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add tempValue, #2 ' and make them "32 bits"
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rdword frequency2, tempValue ' reg 2+3
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shl frequency2, #20
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add tempValue, #2
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rdword frequency3, tempValue ' reg 4+5
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shl frequency3, #20
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add tempValue, #2
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rdbyte noisePeriod, tempValue ' reg 6
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and noisePeriod, #$1f
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add tempValue, #1
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rdbyte enableRegister, tempValue ' reg 7
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min noisePeriod, #1
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add tempValue, #1
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rdbyte amplitude1, tempValue ' reg 8
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and amplitude1, #31
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add tempValue, #1
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rdbyte amplitude2, tempValue ' reg 9
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and amplitude2, #31
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add tempValue, #1
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rdbyte amplitude3, tempValue ' reg 10
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and amplitude3, #31
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add tempValue, #1
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rdbyte envelopePeriod, tempValue ' reg 11
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add tempValue, #1
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shl noisePeriod, #20
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rdbyte temp1, tempValue ' reg 12
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shl temp1, #8
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or envelopePeriod, temp1 wz
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if_z mov envelopePeriod, half_period ' 0 == half the period of 1
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if_nz shl envelopePeriod, #16
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add tempValue, #1
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rdbyte envelopeShape, tempValue ' reg 13
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movd oscValues, enableRegister
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getRegisters_ret ret
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'
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' Calculate AY samples channel 1-3 and store in out1-out3
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'
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AY
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'───────────────────────────────────────────────────────────
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'───────────────────────────────────────────────────────────
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' Envelope shaping -> envelopeAmplitude
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'───────────────────────────────────────────────────────────
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Envelope sub envCounter, envSubValue wc ' Handles envelope incrementing
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if_c add envCounter, envelopePeriod
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if_c add envelopeValue, envelopeInc
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'───────────────────────────────────────────────────────────
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test envelopeShape, #16 wz ' Handle envelope reset bit ( Extra bit added by Ahle2 )
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if_z neg envelopeValue, #0
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if_z mov envelopeInc, #1
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if_z mov envCounter, envelopePeriod
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if_z or envelopeShape, #16
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if_z wrbyte envelopeShape, tempValue '<-IMPORTANT, sets bit 5 in hub ram
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'───────────────────────────────────────────────────────────
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test envelopeShape, #8 wc ' Handle continue = 0
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test envelopeShape, #4 wz
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if_nc_and_z mov envelopeShape, #9
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if_nc_and_nz mov envelopeShape, #15
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'───────────────────────────────────────────────────────────
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test envelopeShape, #2 wz ' Sets the envelope hold level
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muxz envHoldLevel, #15 '
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'───────────────────────────────────────────────────────────
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test envelopeValue, #16 wz ' Check if > 15
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test envelopeShape, #1 wc ' Check hold bit
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if_nz_and_c mov envelopeInc, #0 ' Hold envelope
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if_nz_and_c mov envelopeValue, envHoldLevel '
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'───────────────────────────────────────────────────────────
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if_nz test envelopeShape, #2 wc ' Check and handle alternation
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if_nz_and_c neg envelopeInc, envelopeInc
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if_nz_and_c add envelopeValue, envelopeInc
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'───────────────────────────────────────────────────────────
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mov envelopeAmplitude, envelopeValue
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test envelopeShape, #4 wc ' Check and handle invertion (attack)
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if_nc xor envelopeAmplitude, #15 '(Move Value or ~Value to envelopeAmplitude)
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'───────────────────────────────────────────────────────────
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' Waveform shaping noise -> bit 3 of oscValues
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'───────────────────────────────────────────────────────────
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Noise1 sub phaseAccumulatorN, noiseSubValue wc ' Noise generator
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if_c add phaseAccumulatorN, noisePeriod
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if_c add noiseValue, noiseAdd
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if_c ror noiseValue, #15 wc
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if_c xor oscValues, #8
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'───────────────────────────────────────────────────────────
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' Waveform shaping channel 1 -> out1
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'───────────────────────────────────────────────────────────
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Env1 test amplitude1, #16 wz ' Selects envelope or fixed amplitude
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if_nz mov amplitude1, envelopeAmplitude ' depending on bit 5 of amplitude register 1
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mov arg1, amplitude1
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call #getAmplitude
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'───────────────────────────────────────────────────────────
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Square1 cmp frequency1, freqRef wc
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if_nc sub phaseAccumulator1, oscSubValue wc ' Square wave generator
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if_c add phaseAccumulator1, frequency1 ' channel 1
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if_c xor oscValues, #1
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'───────────────────────────────────────────────────────────
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test oscValues, mask513 wz ' Handles mixing of channel 1
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negnz out1, r1 ' Tone on/off, Noice on/off
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test oscValues, mask4104 wz
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if_z mov out1, r1 ' arg2 = (ToneOn | ToneDisable) & (NoiseOn | NoiseDisable)
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'───────────────────────────────────────────────────────────
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' Waveform shaping channel 2 -> out2
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'───────────────────────────────────────────────────────────
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Env2 test amplitude2, #16 wz ' Selects envelope or fixed amplitude
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if_nz mov amplitude2, envelopeAmplitude ' depending on bit 5 of amplitude register 2
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mov arg1, amplitude2
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call #getAmplitude
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'───────────────────────────────────────────────────────────
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Square2 cmp frequency2, freqRef wc
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if_nc sub phaseAccumulator2, oscSubValue wc ' Square wave generator
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if_c add phaseAccumulator2, frequency2 ' channel 2
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if_c xor oscValues, #2
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'───────────────────────────────────────────────────────────
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test oscValues, mask1026 wz ' Handles mixing of channel 2
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negz out2, r1 ' Tone on/off, Noice on/off
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test oscValues, mask8200 wz
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if_z mov out2, r1 ' arg2 = (ToneOn | ToneDisable) & (NoiseOn | NoiseDisable)
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'───────────────────────────────────────────────────────────
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' Waveform shaping channel 3 -> out3
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'───────────────────────────────────────────────────────────
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Env3 test amplitude3, #16 wz ' Selects envelope or fixed amplitude
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if_nz mov amplitude3, envelopeAmplitude ' depending on bit 5 of amplitude register 3
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mov arg1, amplitude3
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call #getAmplitude
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'───────────────────────────────────────────────────────────
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Square3 cmp frequency3, freqRef wc
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if_nc sub phaseAccumulator3, oscSubValue wc ' Square wave generator
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if_c add phaseAccumulator3, frequency3 ' channel 3
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if_c xor oscValues, #4
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'───────────────────────────────────────────────────────────
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test oscValues, mask2052 wz ' Handles mixing of channel 2
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negz out3, r1 ' Tone on/off, Noice on/off
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test oscValues, mask16392 wz
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if_z mov out3, r1 ' arg2 = (ToneOn | ToneDisable) & (NoiseOn | NoiseDisable)
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AY_ret ret
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'
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' Mix channels and update FRQA/FRQB PWM-values
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'
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mixer mov r1, val31bit ' DC offset
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add r1, out1
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add r1, out2
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add r1, out3
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waitcnt waitCounter, sampleRate ' Wait until the right time to update
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mov FRQA, r1 '| Update PWM values in FRQA/FRQB
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mov FRQB, r1 '|
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mixer_ret ret
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'
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' Get amplitude table r1 = amplitudTable[arg1]
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'
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getAmplitude and arg1, #15
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add arg1, #amplitudeTable ' Lookup the amplitude according
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movs :indexed1, arg1 ' to the current state of the envelope
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nop
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:indexed1 mov r1, 0
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getAmplitude_ret ret
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'
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' Variables, tables, masks and reference values
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'
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amplitudeTable long 1634706
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long 2452059
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long 3678089
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long 5517133
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long 8275700
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long 12413550
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long 18620325
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long 27930488
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long 41895733
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long 62843600
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long 94265400
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long 141398100
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long 212097150
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long 318145725
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long 477218588
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long 715827882
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'Masks and reference values
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mask513 long 513
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mask1026 long 1026
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mask2052 long 2052
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mask4104 long 4104
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mask8200 long 8200
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mask16392 long 16392
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mask32bit long $ffffffff
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mask16bit long $ffff
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half_period long $00008000
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val31bit long $80000000
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noiseAdd long $88008800 'Value to add to the noise generator every noise update
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sampleRate long 0
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freqRef long 10<<20
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'Setup and subroutine parameters
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arg1 long 0
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arg2 long 0
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r1 long 0
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AY_Address long 0
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'AY variables
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envCounter long 1
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envSubValue long ENV_CORR
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oscSubValue long OSC_CORR
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noiseSubValue long NOISE_CORR
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envelopeValue long 0
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envelopeInc long 1
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envHoldLevel res 1
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oscValues res 1
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amplitude1 res 1
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amplitude2 res 1
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amplitude3 res 1
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envelopeAmplitude res 1
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enableRegister res 1
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envelopeShape res 1
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frequency1 res 1
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frequency2 res 1
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frequency3 res 1
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envelopePeriod res 1
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noisePeriod res 1
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phaseAccumulatorN res 1
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phaseAccumulator1 res 1
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phaseAccumulator2 res 1
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phaseAccumulator3 res 1
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noiseValue res 1
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noiseOut res 1
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out1 res 1
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out2 res 1
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out3 res 1
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waitCounter res 1
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tempValue res 1
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temp1 res 1
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fit
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