Optimize single use of global variables in function

autotest/autotest.bat

@@ -114,6 +114,9 @@ rem @echo off
 @call :test structmembertest.c
 @if %errorlevel% neq 0 goto :error
 
+@call :test structarraycopy.c
+@if %errorlevel% neq 0 goto :error
+
 @call :test randsumtest.c
 @if %errorlevel% neq 0 goto :error
 

autotest/structarraycopy.c

@@ -0,0 +1,49 @@
+
+
+struct Point
+{
+	int x, y;	
+};
+
+
+Point	tcorners[8], pcorners[8];
+
+int bm_line(void)
+{
+
+}
+
+void drawCube(void)
+{
+	for(char i=0; i<8; i++)
+	{
+		if (!(i & 1))
+			bm_line();
+		if (!(i & 2))
+			bm_line();
+		if (!(i & 4))
+			bm_line();
+
+		pcorners[i] = tcorners[i];
+	}
+}
+
+int main(void)
+{
+	for(int i=0; i<8; i++)
+	{
+		tcorners[i].x = (i + 1) * 3;
+		tcorners[i].y = (i + 1) * 7;
+	}
+
+	drawCube();
+
+	int	sum = 0;
+	for(int i=0; i<8; i++)
+	{
+		sum += pcorners[i].x;
+		sum -= tcorners[i].y;
+	}
+
+	return sum + 144;
+}

oscar64/CompilerTypes.h

@@ -10,6 +10,8 @@ static const uint64 COPT_OPTIMIZE_AUTO_INLINE_ALL = 0x00000020;
 static const uint64 COPT_OPTIMIZE_AUTO_UNROLL = 0x00000040;
 static const uint64 COPT_OPTIMIZE_CONST_EXPRESSIONS = 0x00000080;
 
+static const uint64 COPT_OPTIMIZE_CODE_SIZE = 0x00000100;
+
 static const uint64 COPT_TARGET_PRG = 0x100000000ULL;
 static const uint64 COPT_TARGET_CRT16 = 0x200000000ULL;
 static const uint64 COPT_TARGET_CRT512 = 0x400000000ULL;
@@ -24,7 +26,7 @@ static const uint64 COPT_DEFAULT = COPT_OPTIMIZE_BASIC | COPT_OPTIMIZE_INLINE |
 
 static const uint64 COPT_OPTIMIZE_DEFAULT = COPT_OPTIMIZE_BASIC | COPT_OPTIMIZE_INLINE | COPT_OPTIMIZE_CONST_EXPRESSIONS;
 
-static const uint64 COPT_OPTIMIZE_SIZE = COPT_OPTIMIZE_BASIC | COPT_OPTIMIZE_INLINE | COPT_OPTIMIZE_CONST_EXPRESSIONS;
+static const uint64 COPT_OPTIMIZE_SIZE = COPT_OPTIMIZE_BASIC | COPT_OPTIMIZE_INLINE | COPT_OPTIMIZE_CONST_EXPRESSIONS | COPT_OPTIMIZE_CODE_SIZE;
 
 static const uint64 COPT_OPTIMIZE_SPEED = COPT_OPTIMIZE_BASIC | COPT_OPTIMIZE_INLINE | COPT_OPTIMIZE_AUTO_INLINE | COPT_OPTIMIZE_AUTO_UNROLL | COPT_OPTIMIZE_CONST_EXPRESSIONS;
 

oscar64/NativeCodeGenerator.cpp

@@ -690,6 +690,42 @@ bool NativeCodeInstruction::UsesZeroPage(int address) const
 		return true;
 	else if (mMode == ASMIM_INDIRECT_Y && (mAddress == address || mAddress + 1 == address))
 		return true;
+	else if (mType == ASMIT_JSR)
+	{
+		if (address >= BC_REG_ACCU && address < BC_REG_ACCU + 4)
+			return true;
+		if (address >= BC_REG_WORK && address < BC_REG_WORK + 4)
+			return true;
+
+		if (mFlags & NCIF_RUNTIME)
+		{
+
+			if (mFlags & NCIF_USE_ZP_32_X)
+			{
+				if (address >= mParam && address < mParam + 4)
+					return true;
+			}
+
+			if (mFlags & NCIF_FEXEC)
+			{
+				if (address >= BC_REG_FPARAMS && address < BC_REG_FPARAMS_END)
+					return true;
+			}
+		}
+		else
+		{
+			if (mLinkerObject)
+			{
+				for (int i = 0; i < mLinkerObject->mNumTemporaries; i++)
+				{
+					if (address >= mLinkerObject->mTemporaries[i] && address < mLinkerObject->mTemporaries[i] + mLinkerObject->mTempSizes[i])
+						return true;
+				}
+			}
+		}
+
+		return false;
+	}
 	else
 		return false;
 }
@@ -778,6 +814,20 @@ bool NativeCodeInstruction::ChangesAccu(void) const
 
 
 
+bool NativeCodeInstruction::UsesAddress(void) const
+{
+	if (mMode != ASMIM_IMPLIED)
+	{
+		return
+			mType == ASMIT_INC || mType == ASMIT_DEC || mType == ASMIT_ASL || mType == ASMIT_LSR || mType == ASMIT_ROL || mType == ASMIT_ROR ||
+			mType == ASMIT_LDA || mType == ASMIT_LDX || mType == ASMIT_LDY ||
+			mType == ASMIT_CMP || mType == ASMIT_CPX || mType == ASMIT_CPY ||
+			mType == ASMIT_ADC || mType == ASMIT_SBC || mType == ASMIT_AND || mType == ASMIT_ORA || mType == ASMIT_EOR;
+	}
+	else
+		return false;
+}
+
 bool NativeCodeInstruction::ChangesAddress(void) const
 {
 	if (mMode != ASMIM_IMPLIED)
@@ -4897,7 +4947,14 @@ NativeCodeBasicBlock * NativeCodeBasicBlock::CopyValue(InterCodeProcedure* proc,
 	int	sreg = BC_REG_TMP + proc->mTempOffset[ins->mSrc[0].mTemp], dreg = BC_REG_TMP + proc->mTempOffset[ins->mSrc[1].mTemp];
 
 	int	size = ins->mConst.mOperandSize;
-	if (size < 4)
+	int	msize = 4;
+
+	if (nproc->mGenerator->mCompilerOptions & COPT_OPTIMIZE_AUTO_UNROLL)
+		msize = 8;
+	else if (nproc->mGenerator->mCompilerOptions & COPT_OPTIMIZE_CODE_SIZE)
+		msize = 2;
+
+	if (size <= msize)
 	{
 		for (int i = 0; i < size; i++)
 		{
@@ -9559,6 +9616,33 @@ bool NativeCodeBasicBlock::JoinTailCodeSequences(NativeCodeProcedure* proc)
 						pblock->mIns.Push(mIns[0]);
 						mIns.Remove(0);
 
+						changed = true;
+					}
+				}
+				else if (mIns[0].mType == ASMIT_LDX && mIns[0].mMode == ASMIM_ZERO_PAGE && !(mIns[0].mLive & LIVE_CPU_REG_A))
+				{
+					if (lblock->mIns[ls - 2].mType == ASMIT_LDA && lblock->mIns[ls - 2].mMode == ASMIM_ZERO_PAGE && lblock->mIns[ls - 2].mAddress == mIns[0].mAddress &&
+						lblock->mIns[ls - 1].mType == ASMIT_CMP && !(lblock->mIns[ls - 1].mLive & LIVE_CPU_REG_A))
+					{
+						lblock->mIns[ls - 2].mType = ASMIT_LDX; lblock->mIns[ls - 2].mLive |= LIVE_CPU_REG_X;
+						lblock->mIns[ls - 1].mType = ASMIT_CPX; lblock->mIns[ls - 1].mLive |= LIVE_CPU_REG_X;
+
+						pblock->mIns.Push(mIns[0]);
+						mIns.Remove(0);
+
+						changed = true;
+					}
+				}
+				else if (mIns[0].mType == ASMIT_LDA && mIns[0].mMode == ASMIM_ZERO_PAGE)
+				{
+					if (lblock->mIns[ls - 2].mType == ASMIT_LDA && lblock->mIns[ls - 2].mMode == ASMIM_ZERO_PAGE && lblock->mIns[ls - 2].mAddress == mIns[0].mAddress &&
+						lblock->mIns[ls - 1].mType == ASMIT_CMP)
+					{
+						pblock->mIns.Push(mIns[0]);
+						mIns.Remove(0);
+
+						lblock->mIns[ls - 1].mLive |= LIVE_CPU_REG_A;
+
 						changed = true;
 					}
 				}
@@ -9737,6 +9821,103 @@ bool NativeCodeBasicBlock::FindImmediateStore(int at, int reg, const NativeCodeI
 	return false;
 }
 
+bool NativeCodeBasicBlock::CheckSingleUseGlobalLoad(int reg, int at, const NativeCodeInstruction& ains)
+{
+	if (!mPatched)
+	{
+		mPatched = true;
+
+		if (at == 0)
+		{
+			if (!mEntryRequiredRegs[reg])
+				return true;
+
+			if (mNumEntries > 1)
+				return false;
+		}
+
+		while (at < mIns.Size())
+		{
+			NativeCodeInstruction& ins(mIns[at]);
+
+			if (ins.mMode == ASMIM_ZERO_PAGE && ins.mAddress == reg)
+			{
+				if (ins.UsesAddress())
+				{
+					if (ins.ChangesAddress())
+						return false;
+					return !(ins.mLive & LIVE_MEM);
+				}
+				else
+					return true;
+			}
+			else if (ins.mType == ASMIT_JSR)
+			{
+				if (ins.mFlags & NCIF_RUNTIME)
+				{
+					if (ins.UsesZeroPage(reg))
+						return false;
+				}
+				else
+					return false;	
+			}
+			else if (ins.mMode == ASMIM_INDIRECT_Y && (ins.mAddress == reg || ins.mAddress + 1 == reg))
+				return false;
+			else if (ins.ChangesZeroPage(reg))
+				return true;
+			else if (ains.MayBeChangedOnAddress(ins))
+				return false;
+
+			at++;
+		}
+
+		if (mTrueJump && !mTrueJump->CheckSingleUseGlobalLoad(reg, 0, ains))
+			return false;
+		if (mFalseJump && !mFalseJump->CheckSingleUseGlobalLoad(reg, 0, ains))
+			return false;
+	}
+
+	return true;
+}
+
+bool NativeCodeBasicBlock::PatchSingleUseGlobalLoad(int reg, int at, const NativeCodeInstruction& ains)
+{
+	bool	changed = false;
+
+	if (!mPatched)
+	{
+		mPatched = true;
+
+		if (at == 0 && !mEntryRequiredRegs[reg])
+			return false;
+
+		while (at < mIns.Size())
+		{
+			NativeCodeInstruction& ins(mIns[at]);
+
+			if (ins.mMode == ASMIM_ZERO_PAGE && ins.mAddress == reg)
+			{
+				if (ins.UsesAddress())
+				{
+					assert(!(ins.mLive & LIVE_MEM));
+					ins.CopyMode(ains);
+					return true;
+				}
+
+				return false;
+			}
+
+			at++;
+		}
+
+		if (mTrueJump && mTrueJump->PatchSingleUseGlobalLoad(reg, 0, ains))
+			changed = true;
+		if (mFalseJump && mFalseJump->PatchSingleUseGlobalLoad(reg, 0, ains))
+			changed = true;
+	}
+
+	return changed;
+}
 
 bool NativeCodeBasicBlock::CheckGlobalAddressSumYPointer(int reg, int at, int yval)
 {
@@ -9744,6 +9925,15 @@ bool NativeCodeBasicBlock::CheckGlobalAddressSumYPointer(int reg, int at, int yv
 	{
 		mPatched = true;
 
+		if (at == 0)
+		{
+			if (!mEntryRequiredRegs[reg] && !mEntryRequiredRegs[reg + 1])
+				return true;
+
+			if (mNumEntries > 1)
+				yval = -1;
+		}
+
 		while (at < mIns.Size())
 		{
 			NativeCodeInstruction& ins(mIns[at]);
@@ -9764,6 +9954,12 @@ bool NativeCodeBasicBlock::CheckGlobalAddressSumYPointer(int reg, int at, int yv
 				yval = (yval + 1) & 255;
 			else if (ins.mType == ASMIT_DEY && yval >= 0)
 				yval = (yval - 1) & 255;
+			else if (ins.mType == ASMIT_JSR)
+			{
+				if (ins.UsesZeroPage(reg) || ins.UsesZeroPage(reg + 1))
+					return false;
+				yval = -1;
+			}
 			else if (ins.ChangesYReg())
 				yval = -1;
 
@@ -9786,6 +9982,8 @@ bool NativeCodeBasicBlock::PatchGlobalAddressSumYPointer(int reg, int at, int yv
 	if (!mPatched)
 	{
 		mPatched = true;
+		if (at == 0 && !mEntryRequiredRegs[reg] && !mEntryRequiredRegs[reg + 1])
+			return false;
 
 		while (at < mIns.Size())
 		{
@@ -10838,6 +11036,10 @@ bool NativeCodeBasicBlock::MoveLoadStoreOutOfXYRangeUp(int at)
 			return false;
 		if (mIns[j].ChangesAddress() && mIns[j].SameEffectiveAddress(mIns[at + 1]))
 			return false;
+		if (mIns[at + 1].mMode == ASMIM_ABSOLUTE_X && mIns[j].ChangesXReg())
+			return false;
+		if (mIns[at + 1].mMode == ASMIM_ABSOLUTE_Y && mIns[j].ChangesYReg())
+			return false;
 
 		if (mIns[j].mType == ASMIT_LDA)
 		{
@@ -10973,32 +11175,54 @@ bool NativeCodeBasicBlock::MoveStoreXUp(int at)
 {
 	bool	done = false;
 
+	int	n = 0, inc = 0;;
+	int	reg = mIns[at].mAddress;
+
 	while (at > 0)
 	{
-		if (mIns[at - 1].ChangesXReg() || mIns[at - 1].mType == ASMIT_STX)
+		if (mIns[at - 1].mType == ASMIT_INX)
-			return done;
-		if (mIns[at].mMode == ASMIM_ZERO_PAGE)
 		{
-			if ((mIns[at - 1].mMode == ASMIM_ZERO_PAGE || mIns[at - 1].mMode == ASMIM_INDIRECT_Y) && mIns[at - 1].mAddress == mIns[at].mAddress)
+			n++;
-				return done;
+			inc++;
-			if (mIns[at - 1].mMode == ASMIM_INDIRECT_Y && mIns[at - 1].mAddress + 1 == mIns[at].mAddress)
+		}
-				return done;
+		else if (mIns[at - 1].mType == ASMIT_DEX)
+		{
+			n++;
+			inc--;
 		}
 		else
 		{
-			if (mIns[at - 1].mMode == ASMIM_ABSOLUTE && mIns[at - 1].mLinkerObject == mIns[at].mLinkerObject && mIns[at - 1].mAddress == mIns[at].mAddress)
+			if (mIns[at - 1].mType == ASMIT_LDX || mIns[at - 1].mType == ASMIT_TAX)
 				return done;
-			else if ((mIns[at - 1].mMode == ASMIM_ABSOLUTE_X || mIns[at - 1].mMode == ASMIM_ABSOLUTE_Y) && mIns[at - 1].mLinkerObject == mIns[at].mLinkerObject)
+			else if (mIns[at - 1].ChangesXReg() || mIns[at - 1].mType == ASMIT_STX)
 				return done;
+			else if (mIns[at + n].mMode == ASMIM_ZERO_PAGE)
+			{
+			if ((mIns[at - 1].mMode == ASMIM_ZERO_PAGE || mIns[at - 1].mMode == ASMIM_INDIRECT_Y) && mIns[at - 1].mAddress == reg)
+				return done;
+			if (mIns[at - 1].mMode == ASMIM_INDIRECT_Y && mIns[at - 1].mAddress + 1 == reg)
+				return done;
+			}
+			else
+			{
+			if (mIns[at - 1].mMode == ASMIM_ABSOLUTE && mIns[at - 1].mLinkerObject == mIns[at + n].mLinkerObject && mIns[at - 1].mAddress == mIns[at + n].mAddress)
+				return done;
+			else if ((mIns[at - 1].mMode == ASMIM_ABSOLUTE_X || mIns[at - 1].mMode == ASMIM_ABSOLUTE_Y) && mIns[at - 1].mLinkerObject == mIns[at + n].mLinkerObject)
+				return done;
+			}
+
+			mIns[at].mLive |= mIns[at - 1].mLive;
+
+			NativeCodeInstruction	ins = mIns[at - 1];
+			if (ins.mMode == ASMIM_ABSOLUTE_X)
+				ins.mAddress -= inc;
+
+			for (int i = 0; i <= n; i++)
+				mIns[at - 1 + i] = mIns[at + i];
+			mIns[at + n] = ins;
+			done = true;
 		}
-
-		mIns[at].mLive |= mIns[at - 1].mLive;
-
-		NativeCodeInstruction	ins = mIns[at - 1];
-		mIns[at - 1] = mIns[at];
-		mIns[at] = ins; 
 		at--;
-		done = true;
 	}
 
 	return done;
@@ -13857,8 +14081,16 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(NativeCodeProcedure* proc, int pass
 #if 1
 		for (int i = 0; i + 2 < mIns.Size(); i++)
 		{
-			if ((mIns[i + 0].mType == ASMIT_TAX || mIns[i + 0].mType == ASMIT_TAY) &&
+			if (mIns[i + 0].mType == ASMIT_TAX &&
-				mIns[i + 1].mType == ASMIT_LDA && (mIns[i + 1].mMode == ASMIM_ABSOLUTE || mIns[i + 1].mMode == ASMIM_ZERO_PAGE) &&
+				mIns[i + 1].mType == ASMIT_LDA && (mIns[i + 1].mMode == ASMIM_ABSOLUTE || mIns[i + 1].mMode == ASMIM_ABSOLUTE_Y || mIns[i + 1].mMode == ASMIM_ZERO_PAGE) &&
+				mIns[i + 2].mType == ASMIT_STA && mIns[i + 2].mMode == ASMIM_ZERO_PAGE && !(mIns[i + 2].mLive & (LIVE_CPU_REG_Z | LIVE_CPU_REG_A)))
+			{
+				if (MoveLoadStoreOutOfXYRangeUp(i))
+					changed = true;
+			}
+			else if (
+				mIns[i + 0].mType == ASMIT_TAY &&
+				mIns[i + 1].mType == ASMIT_LDA && (mIns[i + 1].mMode == ASMIM_ABSOLUTE || mIns[i + 1].mMode == ASMIM_ABSOLUTE_X || mIns[i + 1].mMode == ASMIM_ZERO_PAGE) &&
 				mIns[i + 2].mType == ASMIT_STA && mIns[i + 2].mMode == ASMIM_ZERO_PAGE && !(mIns[i + 2].mLive & (LIVE_CPU_REG_Z | LIVE_CPU_REG_A)))
 			{
 				if (MoveLoadStoreOutOfXYRangeUp(i))
@@ -15790,6 +16022,41 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(NativeCodeProcedure* proc, int pass
 						progress = true;
 					}
 #endif
+					else if (
+						mIns[i + 0].mType == ASMIT_TXA &&
+						mIns[i + 1].mType == ASMIT_CLC &&
+						mIns[i + 2].mType == ASMIT_ADC && mIns[i + 2].mMode == ASMIM_IMMEDIATE && mIns[i + 2].mAddress <= 2 &&
+						mIns[i + 3].mType == ASMIT_TAX && !(mIns[i + 3].mLive & LIVE_CPU_REG_C))
+					{
+						mIns[i + 0].mType = ASMIT_NOP; mIns[i + 0].mMode = ASMIM_IMPLIED;
+						mIns[i + 1].mType = ASMIT_INX; mIns[i + 1].mMode = ASMIM_IMPLIED; mIns[i + 1].mLive |= LIVE_CPU_REG_X;
+						if (mIns[i + 2].mAddress == 2)
+							mIns[i + 2].mType = ASMIT_INX;
+						else
+							mIns[i + 2].mType = ASMIT_NOP;
+						mIns[i + 2].mMode = ASMIM_IMPLIED; mIns[i + 2].mLive |= LIVE_CPU_REG_X;
+						if (mIns[i + 3].mLive & LIVE_CPU_REG_A)
+							mIns[i + 3].mType = ASMIT_TXA;
+						progress = true;
+					}
+					else if (
+						mIns[i + 0].mType == ASMIT_TXA &&
+						mIns[i + 1].mType == ASMIT_SEC &&
+						mIns[i + 2].mType == ASMIT_SBC && mIns[i + 2].mMode == ASMIM_IMMEDIATE && mIns[i + 2].mAddress <= 2 &&
+						mIns[i + 3].mType == ASMIT_TAX && !(mIns[i + 3].mLive & LIVE_CPU_REG_C))
+					{
+						mIns[i + 0].mType = ASMIT_NOP; mIns[i + 0].mMode = ASMIM_IMPLIED;
+						mIns[i + 1].mType = ASMIT_DEX; mIns[i + 1].mMode = ASMIM_IMPLIED; mIns[i + 1].mLive |= LIVE_CPU_REG_X;
+						if (mIns[i + 2].mAddress == 2)
+							mIns[i + 2].mType = ASMIT_DEX;
+						else
+							mIns[i + 2].mType = ASMIT_NOP;
+						mIns[i + 2].mMode = ASMIM_IMPLIED; mIns[i + 2].mLive |= LIVE_CPU_REG_X;
+						if (mIns[i + 3].mLive & LIVE_CPU_REG_A)
+							mIns[i + 3].mType = ASMIT_TXA;
+						progress = true;
+					}
+
 					else if (
 						mIns[i + 0].mType == ASMIT_TYA &&
 						mIns[i + 1].mType == ASMIT_CLC &&
@@ -16183,6 +16450,22 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(NativeCodeProcedure* proc, int pass
 					}
 				}
 #endif
+				if (i + 1 < mIns.Size())
+				{
+					if (
+						mIns[i + 0].mType == ASMIT_LDA && mIns[i + 0].mMode == ASMIM_ABSOLUTE &&
+						mIns[i + 1].mType == ASMIT_STA && mIns[i + 1].mMode == ASMIM_ZERO_PAGE && !(mIns[i + 1].mLive & (LIVE_CPU_REG_A | LIVE_CPU_REG_Z)))
+					{
+						proc->ResetPatched();
+						if (CheckSingleUseGlobalLoad(mIns[i + 1].mAddress, i + 2, mIns[i]))
+						{
+							proc->ResetPatched();
+							if (PatchSingleUseGlobalLoad(mIns[i + 1].mAddress, i + 2, mIns[i]))
+								progress = true;
+						}
+					}
+				}
+
 				if (i + 5 < mIns.Size())
 				{
 					if (
@@ -16221,7 +16504,8 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(NativeCodeProcedure* proc, int pass
 							mIns[i + 5].mType = ASMIT_NOP; mIns[i + 5].mMode = ASMIM_IMPLIED;
 
 							proc->ResetPatched();
-							progress = PatchGlobalAddressSumYPointer(mIns[i + 2].mAddress, i + 6, -1, mIns[i + 3].mLinkerObject, mIns[i + 3].mAddress);
+							if (PatchGlobalAddressSumYPointer(mIns[i + 2].mAddress, i + 6, -1, mIns[i + 3].mLinkerObject, mIns[i + 3].mAddress))
+								progress = true;
 						}
 					}
 #endif

oscar64/NativeCodeGenerator.h

@@ -84,6 +84,7 @@ public:
 	bool LoadsAccu(void) const;
 	bool ChangesAccuAndFlag(void) const;
 	bool ChangesAddress(void) const;
+	bool UsesAddress(void) const;
 	bool ChangesAccu(void) const;
 	bool UsesAccu(void) const;
 	bool ChangesCarry(void) const;
@@ -273,6 +274,9 @@ public:
 
 	bool CheckGlobalAddressSumYPointer(int reg, int at, int yval);
 	bool PatchGlobalAddressSumYPointer(int reg, int at, int yval, LinkerObject * lobj, int address);
+
+	bool CheckSingleUseGlobalLoad(int reg, int at, const NativeCodeInstruction& ains);
+	bool PatchSingleUseGlobalLoad(int reg, int at, const NativeCodeInstruction& ains);
 };
 
 class NativeCodeProcedure

samples/games/hscrollshmup.c

@@ -330,59 +330,53 @@ struct Enemy
 	int		px;
 	byte	py;
 	sbyte	dx;
-	byte	n;
 }	enemies[5];
 
-	int	spx = 40;
+int	spx = 40;
-	int	vpx = 16;
+int	vpx = 16;
-	int	ax = 0;
+int	ax = 0;
-	char	spy = 100;
+char	spy = 100;
-	char	fdelay = 0;
+char	fdelay = 0;
+char	edelay = 5;
+char	ecount = 0;
 
 void enemies_move(void)
 {
-	bool	elive = false;
-
 	for(char i=0; i<5; i++)
 	{
-		if (enemies[i].n)
+		if (enemies[i].dx)
 		{
-			enemies[i].n--;
 			enemies[i].px += enemies[i].dx;
 
 			int	rx = enemies[i].px - spx;
-			if (enemies[i].dx < 0)
+			if (rx < -192 || rx >= 480)
 			{
-				if (rx < -24)
+				enemies[i].dx = 0;
-					enemies[i].n = 0;
+				ecount--;
-			}
-			else
-			{
-				if (rx > 320)
-					enemies[i].n = 0;
 			}
 
 			spr_move(2 + i, rx + 24, enemies[i].py + 50);
-
-			elive = true;
 		}
 	}
+}
 
-	if (!elive)
+void enemies_spwan(void)
-	{
+{
-		for(char i=0; i<5; i++)
+	char	u = rand();
-		{
-			sbyte	v = 4 + (rand() & 1);
-			enemies[i].py = 20 + 30 * i;
-			enemies[i].dx = vpx < 0 ? v : -v;
-			enemies[i].px = (vpx < 0 ? spx - 56 : spx + 320) + (rand() & 31);
-			enemies[i].n = 100;
 
-			int	rx = enemies[i].px - spx;
+	char	e = ecount;
 
-			spr_set(2 + i, true, rx + 24, enemies[i].py + 50, 96, VCOL_YELLOW, true, false, false);
+	__assume(e < 5);
-		}
+
-	}
+	sbyte	v = 1 + (u & 3);
+	enemies[ecount].py = 20 + 30 * e;
+	enemies[ecount].dx = vpx < 0 ? v : -v;
+	enemies[ecount].px = (vpx < 0 ? spx - 56 : spx + 320) + ((u >> 1) & 31);
+
+	int	rx = enemies[ecount].px - spx;
+
+	spr_set(2 + ecount, true, rx + 24, enemies[ecount].py + 50, vpx < 0 ? 97 : 96, VCOL_YELLOW, true, false, false);
+	ecount++;
 }
 
 int main(void)
@@ -430,7 +424,7 @@ int main(void)
 
 	spr_set(0, true, 160, 100, 64,          VCOL_BLUE, true, false, false);
 	spr_set(7, true, 160, 100, 64 + 16, VCOL_MED_GREY, true, false, false);
-	vic.spr_priority = 2;
+	vic.spr_priority = 0x80;
 
 	vpx = 2;
 	for(;;)
@@ -497,15 +491,23 @@ int main(void)
 		vic.color_border++;
 		vic_waitLine(82);
 		vic.color_border++;
-		tiles_draw(spx);
+		tiles_draw(spx & 4095);
 		vic.color_border--;
-		enemies_move();
+		if (edelay)
+		{
+			edelay--;
+			if (edelay < 5)
+				enemies_spwan();
+		}
+		else
+		{
+			enemies_move();
+			if (!ecount)
+				edelay = 64 + (rand() & 63);
+		}
 		vic.color_border--;
 
-		spx += vpx >> 1;
+		spx += vpx >> 2;
-
-
-		spx &= 4095;
 	}
 
 	return 0;