diff --git a/Makefile b/Makefile
index 3e2615c..dc0bc28 100755
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ CXXFLAGS=-Wall -I .. -I . -I apple -I sdl -I/usr/local/include/SDL2 -O3 -g
 
 TSRC=cpu.cpp util/testharness.cpp
 
-COMMONOBJS=cpu.o apple/appledisplay.o apple/applekeyboard.o apple/applemmu.o apple/applevm.o apple/diskii.o apple/nibutil.o RingBuffer.o globals.o apple/parallelcard.o apple/fx80.o apple/sy6522.o apple/ay8910.o lcg.o
+COMMONOBJS=cpu.o apple/appledisplay.o apple/applekeyboard.o apple/applemmu.o apple/applevm.o apple/diskii.o apple/nibutil.o RingBuffer.o globals.o apple/parallelcard.o apple/fx80.o lcg.o
 
 SDLOBJS=sdl/sdl-speaker.o sdl/sdl-display.o sdl/sdl-keyboard.o sdl/sdl-paddles.o sdl/sdl-filemanager.o sdl/aiie.o sdl/sdl-printer.o sdl/sdl-clock.o
 
diff --git a/apple/ay8910.cpp b/apple/ay8910.cpp
deleted file mode 100644
index 8174be2..0000000
--- a/apple/ay8910.cpp
+++ /dev/null
@@ -1,374 +0,0 @@
-#include "ay8910.h"
-#include <stdio.h>
-
-#include "globals.h"
-
-// Map our linear 4-bit amplitude to 8-bit output level
-static const uint8_t volumeLevels[16] = { 0x00, 0x04, 0x05, 0x07, 
-					  0x0B, 0x10, 0x16, 0x23,
-					  0x2B, 0x44, 0x5A, 0x73,
-					  0x92, 0xB0, 0xD9, 0xFF };
-
-// Envelope constants
-enum {
-  AY_ENV_HOLD   = 1,
-  AY_ENV_ALT    = 2,
-  AY_ENV_ATTACK = 4,
-  AY_ENV_CONT   = 8
-};
-
-/* Envelope handling
- * (Per General Instruments AY-3-8910 documentation.)
- *
- * Envelope period is set in the 16-bit value r[0x0C]:r[0x0B] (where 0 = 1).
- * The resulting frequency is from 0.12Hz to 7812.5 Hz.
- *
- * The shape of the envelope is selected by r[0x0D] and uses the
- * constants above.
- *
- * If AY_ENV_HOLD is set, then when the envelope reaches terminal (0
- * or 15) it stays there.
- *
- * If AY_ENV_ALT is set, the direction reverses each time it reaches
- * terminal. (If both AY_ENV_HOLD and AY_ENV_ALT are set, then the
- * envelope counter returns to its initial count before holding.)
- *
- * If AY_ENV_ATTACK is set, the counter is ascending (0-to-15); otherwise 
- * it is descending (15-to-0).
- *
- * If AY_ENV_CONT is *clear* (0), then the counter resets to 0 after
- * one cycle and holds there. If it is 1, it does whatever HOLD
- * says. (So AY_ENV_CONT==0 takes priority over AY_ENV_HOLD).
- *
- *
- */ 
-
-AY8910::AY8910() : lcg(0)
-{
-  Reset();
-}
-
-void AY8910::Reset()
-{
-  curRegister = 0;
-
-  // FIXME: what are the right default values?
-  for (uint8_t i=0; i<16; i++)
-    r[i] = 0x00;
-  waveformFlipTimer[0] = waveformFlipTimer[1] = waveformFlipTimer[2] = 0;
-  outputState[0] = outputState[1] = outputState[2] = 0;
-  envCounter = 0;
-  envelopeTimer = envelopeTime = 0;
-  envDirection = 1;
-  noiseFlipTimer = 0;
-  noiseFlag = true;
-
-  lcgBitsRemaining = 0;
-
-#if 0
-  // Debugging
-  r[ENV_PERIOD_COARSE] = 0xFF;
-  r[ENV_PERIOD_FINE] = 0xFF;
-  envelopeTimer = 1;
-  envelopeTime = calculateEnvelopeTime();
-  r[ENV_SHAPE] = 0x08; // sawtooth, descending
-  if (r[ENV_SHAPE] & AY_ENV_ATTACK) {
-    // rising
-    envDirection = 1;
-    envCounter = 0;
-  } else {
-    // falling
-    envDirection = -1;
-    envCounter = 15;
-  }
-#endif  
-}
-
-uint8_t AY8910::read(uint8_t reg)
-{
-  // FIXME: does anything ever need to read from this?
-  return 0xFF;
-}
-
-// reg represents BC1, BDIR, /RST in bits 0, 1, 2.
-// val is the state of those three bits.
-// PortA is the state of whatever's currently on PortA when we do it.
-void AY8910::write(uint8_t reg, uint8_t PortA)
-{
-  // Bit 2 (1 << 2 == 0x04) is wired to the Reset pin. If it goes low,
-  // we reset the virtual chip.
-  if ((reg & NRSET) == 0) {
-    Reset();
-    return;
-  }
-
-  // Bit 0 (1 << 0 == 0x01) is the BC1 pin. BC2 is hard-wired to +5v.
-  // We can ignore bit 3, b/c that was just checked above & triggered
-  // a reset.
-  reg &= ~0x04;
-
-  switch (reg) {
-  case IAB: // bDir==0 && BC1 == 0 (IAB)
-    // Puts the DA bus in high-impedance state. Nothing for us to do?
-    return;
-  case DTB: // bDir==0 && BC1 == 1 (DTB)
-    // Contents of the currently addressed register are put in DA. FIXME?
-    return;
-  case DWS: // bDir==1 && BC1 == 0 (DWS)
-    // Write current PortA to PSG
-    r[curRegister] = PortA;
-
-    if (curRegister <= CHAN_A_COARSE) {
-      // FIXME: for all of A/B/C changes, figure out how much time had
-      // elapsed on the previous timer and apply it to the new one
-      cycleTime[0] = cycleTimeForPSG(0);
-      waveformFlipTimer[0] = g_cpu->cycles + cycleTime[0];
-    } else if (curRegister <= CHAN_B_COARSE) {
-      cycleTime[1] = cycleTimeForPSG(1);
-      waveformFlipTimer[1] = g_cpu->cycles + cycleTime[1];
-    } else if (curRegister <= CHAN_C_COARSE) {
-      cycleTime[2] = cycleTimeForPSG(2);
-      waveformFlipTimer[2] = g_cpu->cycles + cycleTime[2];
-    } else if (curRegister == ENAB) {
-      if (r[ENAB] & ENAB_N_TONEA) {
-	cycleTime[0] = waveformFlipTimer[0] = 0;
-      } else {
-	cycleTime[0] = cycleTimeForPSG(0);
-	waveformFlipTimer[0] = g_cpu->cycles + cycleTime[0];
-      }
-      if (r[ENAB] & ENAB_N_TONEB) {
-	cycleTime[1] = waveformFlipTimer[1] = 0;
-      } else {
-	cycleTime[1] = cycleTimeForPSG(1);
-	waveformFlipTimer[1] = g_cpu->cycles + cycleTime[1];
-      }
-      if (r[ENAB] & ENAB_N_TONEC) {
-	cycleTime[2] = waveformFlipTimer[2] = 0;
-      } else {
-	cycleTime[2] = cycleTimeForPSG(2);
-	waveformFlipTimer[2] = g_cpu->cycles + cycleTime[2];
-      }
-    } else if (curRegister >= ENV_PERIOD_FINE && curRegister <= ENV_PERIOD_COARSE) {
-      // Envelope control -- period or shape
-      // FIXME: should envCounter be initialized to the start position?
-      envelopeTime = calculateEnvelopeTime();
-      envelopeTimer = 0; // reset so it will pick up @ next tick
-    } else if (curRegister == ENV_SHAPE) {
-      if (r[ENV_SHAPE] & AY_ENV_ATTACK) {
-	// rising
-	envDirection = 1;
-	envCounter = 0;
-      } else {
-	// falling
-	envDirection = -1;
-	envCounter = 15;
-      }
-    } else if (curRegister == NOISE_PERIOD) {
-      noiseFlipTimer = g_cpu->cycles + cycleTimeForNoise();
-    }
-    return;
-  case INTAK: // bDir==1 && BC1 == 1 (INTAK)
-    // Select current register
-    curRegister = PortA & 0xF;
-    return;
-  }
-}
-
-// The lowest frequency the AY8910 makes is 30.6 Hz, which is ~33431
-// clock cycles.
-//
-// The highest frequency produced is 125kHz, which is ~8 cycles.
-//
-// The highest practicable, given our 24-cycle-main-loop, is
-// 41kHz. Which should be plenty fine.
-//
-// Conversely: we should be able to call update() as slowly as once
-// every 60-ish clock cycles before we start noticing it in the output
-// audio.
-uint16_t AY8910::cycleTimeForPSG(uint8_t psg)
-{
-  // Convert the current registers in to a cycle count for how long
-  // between flips of 0-to-1 from the square wave generator.
-
-  uint16_t regVal = (r[1+(psg*2)] << 8) | (r[0 + (psg*2)]);
-  if (regVal == 0) regVal++;
-
-  // Ft = 4MHz / (32 * regVal); our clock is 1MHz
-  // so we should return (32 * regVal) / 4 ?
-
-  return (32 * regVal) / 4;
-}
-
-uint16_t AY8910::cycleTimeForNoise()
-{
-  uint8_t regval = r[NOISE_PERIOD];
-  if (regval == 0) regval++;
-
-  return (512 * regval) / 4;
-}
-
-// Similar calculation: this one, for the envelope timer.
-// FIXME: I *think* this is right. Not sure. Needs validation.
-uint32_t AY8910::calculateEnvelopeTime()
-{
-  uint32_t regVal = (r[ENV_PERIOD_COARSE] << 8) | (r[ENV_PERIOD_FINE]);
-  if (regVal == 0) regVal++;
-
-  // This constant is wrong by about 2%. But it should be fast b/c
-  // powers of 2.
-  return (32 * regVal) / 4;
-}
-
-void AY8910::update(uint32_t cpuCycleCount)
-{
-#if 0
-  // Debugging: print state of the 16 registers
-  printf("AY8910: ");
-  for (int i=0; i<16; i++) {
-    printf("%02X ", r[i]);
-  }
-  printf("%04X %04X %04X\n", cycleTime[0], cycleTime[1], cycleTime[2]);
-#endif
-  
-  // update the envelope timer if it's time
-  if (envelopeTime != 0) {
-    if (!envelopeTimer) {
-      // timer wasn't set, so start it running
-      envelopeTimer = cpuCycleCount + envelopeTime;
-    }
-    if (envelopeTimer <= cpuCycleCount) {
-      // time to update the envelopeCounter.
-
-      envCounter += envDirection;
-
-      switch (r[ENV_SHAPE]) {
-	// Continue / Attack / Alternate / Hold bits
-      case 0x00: // 0 / 0 / x / x -- descend once, stay @ bottom
-      case 0x01: // 0 / 0 / x / x
-      case 0x02: // 0 / 0 / x / x
-      case 0x03: // 0 / 0 / x / x
-      case 0x04: // 0 / 1 / x / x -- ascend once, jump to bottom
-      case 0x05: // 0 / 1 / x / x
-      case 0x06: // 0 / 1 / x / x
-      case 0x07: // 0 / 1 / x / x
-      case 0x09: // 1 / 0 / 0 / 1 -- descend once, stay @ bottom
-      case 0x0b: // 1 / 0 / 1 / 1 -- descend once, jump to top
-      case 0x0d: // 1 / 1 / 0 / 1 -- ascend once, stay @ top
-      case 0x0f: // 1 / 1 / 1 / 1 -- ascend once, jump to bottom
-
-	// In all these cases, we go from start to finish once. In all
-	// cases except 0x0b and 0x0d, when we're done, we go low.
-
-	if (envDirection > 0) {
-	  // We were ascending: did we hit 15? If so, stop & go terminal
-	  if (envCounter == 15) {
-	    envDirection = 0;
-	    // One ascending case (0x0b) goes high after; all others are low
-	    envCounter = (r[ENV_SHAPE] == 0x0b ? 0x0F : 0x00);
-	  }
-	} else if (envDirection < 0) {
-	  // We were descending: did we hit 0? If so, stop & go terminal
-	  if (envCounter == 0) {
-	    envDirection = 0;
-	    // One descending case (0x0d) goes high after; all others are low
-	    envCounter = (r[ENV_SHAPE] == 0x0d ? 0x0F : 0x00);
-	  }
-	}
-	break;
-
-      case 0x08:
-      case 0x0C:
-	// These two jump back to the start when they get to the end.
-
-	if (envCounter > 15) {
-	  envCounter = 0;
-	} else if (envCounter < 0) {
-	  envCounter = 15;
-	}
-	break;
-	
-      case 0x0A:
-      case 0x0E:
-	break;
-	// These two reverse direction.
-	if (envCounter == 15 || envCounter == 0) {
-	  envDirection = -envDirection;
-	  }
-	break;
-      }
-      
-      // Set up the envelope timer for the next transition
-      // FIXME: can set this to 0 if envDirection is 0, but have to be careful about setup of timer again when envDirection is re-set
-      envelopeTimer += envelopeTime;
-    }
-  }
-
-  // For the noise timer: if it expires, we get another random bit
-  if (noiseFlipTimer && noiseFlipTimer <= cpuCycleCount) {
-    // FIXME: srnd() this somewhere when we initialized? Does it matter?
-
-    if (!lcgBitsRemaining) {
-      lcgBitsRemaining = 8;
-      lcgLastByte = lcg.rnd();
-    }
-    noiseFlag = lcgLastByte & 1;
-    lcgLastByte >>= 1;
-    lcgBitsRemaining--;
-  }
-
-#if 0
-  // DEBUGGING ENVELOPES: just output the envelope
-  g_speaker->mixOutput(volumeLevels[envCounter]);
-  return;
-#endif
-
-  // For any waveformFlipTimer that is > 0: if cpuCycleCount is larger
-  // than the timer, we'll flip state. (It's a square wave!)
-
-  for (uint8_t i=0; i<3; i++) {
-    uint32_t cc = cycleTime[i];
-
-    if (cc) {
-      if (waveformFlipTimer[i] <= cpuCycleCount) {
-	// flip when it's time to flip
-	waveformFlipTimer[i] += cc;
-	outputState[i] = !outputState[i];
-      }
-    } else {
-      outputState[i] = 0;
-    }
-
-    // Figure out what output comes from this channel and send it to
-    // the speaker. The output is controlled by outputState[i] (from
-    // the square wave, above); the amplitude control line for this
-    // output (r[i+8], below) and the tone/noise selection.
-
-    uint8_t amplitude = 0;
-    // If we're trying to output "high" this square-wave cycle, and if
-    // the ToneEnable bit is set for this register, then generate
-    // output.
-    if (!(r[ENAB] & (1 << i)) && outputState[i]) {
-      amplitude = r[i+8] & 0xF;
-      // ... and if bit 0x10 is on, it's modified by the envelope counter.
-      if (r[i+8] & 0x10) 
-	amplitude = envCounter;
-    }
-
-    // test the NoiseEnable bit for this register
-    if (!(r[ENAB] & (1 << (3+i)))) {
-      // FIXME: if the noiseFlag is off, do we keep the tone value
-      // above? Or set to 0?
-      if (noiseFlag) {
-	amplitude = 7; // median "0-value" level (fixme?)
-	// ... and if bit 0x10 is on, it's modified by the envelope counter.
-	if (r[i+8] & 0x10) 
-	  amplitude = envCounter >> 1;
-      } else {
-	amplitude = 0;
-      }
-    }
-
-    g_speaker->mixOutput(volumeLevels[amplitude]);
-  }
-}
-
diff --git a/apple/ay8910.h b/apple/ay8910.h
deleted file mode 100644
index c85de08..0000000
--- a/apple/ay8910.h
+++ /dev/null
@@ -1,78 +0,0 @@
-#ifndef __AY8910_H
-#define __AY8910_H
-
-#include <stdint.h>
-#include "lcg.h"
-
-// Operations...
-enum {
-  IAB   = 0,
-  DTB   = 1,
-  DWS   = 2,
-  INTAK = 3,
-  NRSET = 4
-};
-
-// Registers...
-enum {
-  CHAN_A_FINE       = 0,
-  CHAN_A_COARSE     = 1,
-  CHAN_B_FINE       = 2,
-  CHAN_B_COARSE     = 3,
-  CHAN_C_FINE       = 4,
-  CHAN_C_COARSE     = 5,
-  NOISE_PERIOD      = 6,
-  ENAB              = 7,
-  CHAN_A_AMP        = 8,
-  CHAN_B_AMP        = 9,
-  CHAN_C_AMP        = 10,
-  ENV_PERIOD_FINE   = 11,
-  ENV_PERIOD_COARSE = 12,
-  ENV_SHAPE         = 13
-};
-
-// Enable flags (all negative; enabled-low)
-enum {
-  ENAB_N_TONEA  = 1,
-  ENAB_N_TONEB  = 2,
-  ENAB_N_TONEC  = 4,
-  ENAB_N_NOISEA = 8,
-  ENAB_N_NOISEB = 16,
-  ENAB_N_NOISEC = 32
-};
-
-class AY8910 {
- public:
-  AY8910();
-
-  void Reset();
-
-  uint8_t read(uint8_t reg);
-  void write(uint8_t reg, uint8_t PortA);
-
-  void update(uint32_t cpuCycleCount);
-
- protected:
-  uint16_t cycleTimeForPSG(uint8_t psg);
-  uint16_t cycleTimeForNoise();
-  uint32_t calculateEnvelopeTime();
-
- private:
-  uint8_t curRegister;
-  uint8_t r[16];
-  uint16_t cycleTime[3];         // how long each cycle will last, in clock cycles
-  uint32_t waveformFlipTimer[3]; // when we're going to flip next
-  uint8_t outputState[3];
-  int8_t envCounter; // which bit of the waveform the envelope is on
-  int8_t envDirection;
-  uint32_t envelopeTime;
-  uint32_t envelopeTimer;
-  uint32_t noiseFlipTimer;
-  bool noiseFlag;
-
-  LCG lcg;
-  uint8_t lcgLastByte;
-  uint8_t lcgBitsRemaining;
-};
-
-#endif
diff --git a/teensy/ay8910.cpp b/teensy/ay8910.cpp
deleted file mode 120000
index f13be59..0000000
--- a/teensy/ay8910.cpp
+++ /dev/null
@@ -1 +0,0 @@
-../apple/ay8910.cpp
\ No newline at end of file
diff --git a/teensy/ay8910.h b/teensy/ay8910.h
deleted file mode 120000
index a1daa2d..0000000
--- a/teensy/ay8910.h
+++ /dev/null
@@ -1 +0,0 @@
-../apple/ay8910.h
\ No newline at end of file