Collapse more nested loops.

tristanmorgan · Aug 6, 2024 · ad80fdc · ad80fdc
1 parent f37b8ce
commit ad80fdc
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Showing 2 changed files with 46 additions and 17 deletions.
diff --git a/parser/tokenise.go b/parser/tokenise.go
@@ -51,27 +51,22 @@ func Tokenise(input io.ByteReader) (program []Instruction, err error) {
 			jmpStack = jmpStack[:len(jmpStack)-1]
 			program[pc].operand = jmpPc
 			program[jmpPc].operand = pc
+
+			redOk, reduceInst := reduceInst(program[pc-1])
 			switch {
 			case program[jmpPc-1].IsZeroOp():
 				pc = jmpPc
 				program = program[:pc]
 				pc--
-			case pc-jmpPc == 2 &&
-				(program[pc-1].SameOp(NewInstruction('+')) ||
-					program[pc-1].operator == opSetVal):
+			case pc-jmpPc == 2 && redOk:
 				pc = jmpPc
-				if program[jmpPc-1].SameOp(NewInstruction('+')) {
+				if (program[jmpPc-1].operator == opAddVal ||
+					program[jmpPc-1].operator == opSetVal) &&
+					reduceInst.operator == opSetVal {
 					pc--
 				}
 				program = program[:pc]
-				program = append(program, Instruction{opSetVal, 0})
-			case pc-jmpPc == 2 &&
-				(program[pc-1].SameOp(NewInstruction('>')) ||
-					program[pc-1].operator == opSkip):
-				offset := program[pc-1].operand
-				pc = jmpPc
-				program = program[:pc]
-				program = append(program, Instruction{opSkip, offset})
+				program = append(program, reduceInst)
 			case pc-jmpPc == 5: // looking for opMulVal and opMove
 				pointers, factors, ok := evalFactors(program[jmpPc+1 : pc])
 
@@ -138,3 +133,28 @@ func evalFactors(program []Instruction) (pointers, factors []int, ok bool) {
 	}
 	return
 }
+
+func reduceInst(inst Instruction) (bool, Instruction) {
+	switch inst.operator {
+	case opAddDp:
+		return true, Instruction{opSkip, inst.operand}
+	case opSkip:
+		return true, inst
+	case opAddVal:
+		if inst.operand == 1 || inst.operand == -1 {
+			return true, Instruction{opSetVal, 0}
+		}
+		return false, Instruction{opNoop, 0}
+	case opSetVal:
+		if inst.operand == 0 {
+			return true, inst
+		}
+		return false, Instruction{opNoop, 0}
+	case opMove:
+		return true, inst
+	case opMovN:
+		return true, inst
+	default:
+		return false, Instruction{opNoop, 0}
+	}
+}
diff --git a/parser/tokenise_test.go b/parser/tokenise_test.go
@@ -17,7 +17,7 @@ func TestTokenise(t *testing.T) {
 	}{
 		{
 			"small_prog",
-			">>>>>++[-]zero+++++>+++++[->>+<<]move>>[>>-<<-]movn",
+			">>>>>++[-]zero+++++>+++++[[->>+<<]move]>>[[>>-<<-]movn]",
 			[]Instruction{
 				{opNoop, 0},
 				{opAddDp, 5},
@@ -31,7 +31,7 @@ func TestTokenise(t *testing.T) {
 		},
 		{
 			"op_mul",
-			"+[<++++++>-]>[->>---<<]",
+			"+[<++++++>-]>[+>>+++<<]",
 			[]Instruction{
 				{opNoop, 0},
 				{opSetVal, 1},
@@ -71,14 +71,15 @@ func TestTokenise(t *testing.T) {
 		},
 		{
 			"op_move",
-			">[->>+<<]>[<<<+>>>-]++",
+			">[->>+<<]>[<<<+>>>-]++[[>-<-]]",
 			[]Instruction{
 				{opNoop, 0},
 				{opAddDp, 1},
 				{opMove, 2},
 				{opAddDp, 1},
 				{opMove, -3},
 				{opSetVal, 2},
+				{opMovN, 1},
 			},
 		},
 		{
@@ -96,7 +97,7 @@ func TestTokenise(t *testing.T) {
 		},
 		{
 			"op_jmp_z_nz",
-			">[->>,>+<<<]",
+			">[->>,>+<<<]>[<<+>>--]",
 			[]Instruction{
 				{opNoop, 0},
 				{opAddDp, 1},
@@ -108,15 +109,23 @@ func TestTokenise(t *testing.T) {
 				{opAddVal, 1},
 				{opAddDp, -3},
 				{opJmpNz, 2},
+				{opAddDp, 1},
+				{opJmpZ, 16},
+				{opAddDp, -2},
+				{opAddVal, 1},
+				{opAddDp, 2},
+				{opAddVal, -2},
+				{opJmpNz, 11},
 			},
 		},
 		{
 			"op_nested",
-			">[[[[[[[>]]]]]]][comment.]",
+			">[[[[[[[>]]]]]]][comment.]+++[[-]]",
 			[]Instruction{
 				{opNoop, 0},
 				{opAddDp, 1},
 				{opSkip, 1},
+				{opSetVal, 0},
 			},
 		},
 	}