fix rept 0 count support

assembler/assembler_asm6_test.go

@@ -266,6 +266,48 @@ IF i==0
 ENDIF
 `
 
+var asm6ElseOutsideOfContext = `
+.segment "HEADER"
+ELSE
+`
+
+var asm6MultipleElse = `
+.segment "HEADER"
+i = 1
+IF i > 0
+ELSE
+ELSE
+`
+
+var asm6EndifOutsideOfContext = `
+.segment "HEADER"
+ENDIF
+`
+
+var asm6MissingEndif = `
+.segment "HEADER"
+i = 1
+IF i > 0
+`
+
+var asm6ElseifOutsideOfContext = `
+.segment "HEADER"
+ELSEIF 1 > 0
+`
+
+var asm6ElseifReferenceProgramCounter = `
+.segment "HEADER"
+IF 1 > 0
+ELSEIF $ > 0
+ENDIF
+`
+
+var asm6IfReferenceProgramCounter = `
+.segment "HEADER"
+IF $ > 0
+ENDIF
+`
+
 func TestAssemblerAsm6IfElseElseIfEndif(t *testing.T) {
 	b, err := runAsm6Test(t, unitTestConfig, asm6IfEndifTestCode)
 	assert.NoError(t, err)
@@ -274,6 +316,27 @@ func TestAssemblerAsm6IfElseElseIfEndif(t *testing.T) {
 		0x3, // 1 item
 	}
 	assert.Equal(t, expected, b)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6ElseOutsideOfContext)
+	assert.ErrorIs(t, err, errConditionOutsideIfContext)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6MultipleElse)
+	assert.ErrorIs(t, err, errMultipleElseFound)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6EndifOutsideOfContext)
+	assert.ErrorIs(t, err, errConditionOutsideIfContext)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6MissingEndif)
+	assert.ErrorIs(t, err, errMissingEndif)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6ElseifOutsideOfContext)
+	assert.ErrorIs(t, err, errConditionOutsideIfContext)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6ElseifReferenceProgramCounter)
+	assert.ErrorIs(t, err, errExpressionCantReferenceProgramCounter)
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6IfReferenceProgramCounter)
+	assert.ErrorIs(t, err, errExpressionCantReferenceProgramCounter)
 }
 
 var asm6IfIfdefTestCode = `
@@ -292,6 +355,9 @@ ELSE
 	DB 4
 ENDIF
 
+IFDEF k
+	DB 6
+ENDIF
 `
 
 func TestAssemblerAsm6IfdefIfndef(t *testing.T) {
@@ -377,6 +443,27 @@ ENDR
 DB 0xff
 `
 
+var asm6ReptReferenceProgramCounter = `
+.segment "HEADER"
+REPT $
+ENDR
+`
+
+var asm6Rept0 = `
+.segment "HEADER"
+REPT 0
+  DB 1
+ENDR
+`
+
+var asm6Rept0Eval = `
+.segment "HEADER"
+i = 0
+REPT i
+  DB 1
+ENDR
+`
+
 func TestAssemblerAsm6Rept(t *testing.T) {
 	b, err := runAsm6Test(t, unitTestConfig, asm6ReptCode)
 	assert.NoError(t, err)
@@ -387,6 +474,17 @@ func TestAssemblerAsm6Rept(t *testing.T) {
 		0xff, // 1 item
 	}
 	assert.Equal(t, expected, b)
+
+	b, err = runAsm6Test(t, unitTestConfig, asm6Rept0)
+	assert.NoError(t, err)
+	assert.True(t, len(b) == 0, "expected no output")
+
+	b, err = runAsm6Test(t, unitTestConfig, asm6Rept0Eval)
+	assert.NoError(t, err)
+	assert.True(t, len(b) == 0, "expected no output")
+
+	_, err = runAsm6Test(t, unitTestConfig, asm6ReptReferenceProgramCounter)
+	assert.ErrorIs(t, err, errExpressionCantReferenceProgramCounter)
 }
 
 func runAsm6Test(t *testing.T, testConfig, testCode string) ([]byte, error) {

assembler/context.go

@@ -1,7 +1,5 @@
 package assembler
 
-import "errors"
-
 type context struct {
 	processNodes bool
 	hasElse      bool // to detect invalid multiple else usages
@@ -15,7 +13,7 @@ func processElseCondition(expEval *expressionEvaluation) error {
 		return errConditionOutsideIfContext
 	}
 	if expEval.currentContext.hasElse {
-		return errors.New("multiple else found")
+		return errMultipleElseFound
 	}
 
 	expEval.currentContext.hasElse = true

assembler/expression_evaluation_step.go

@@ -13,7 +13,10 @@ import (
 
 var (
 	errExpressionCantReferenceProgramCounter = errors.New("expression can not reference program counter")
-	errConditionOutsideIfContext             = errors.New("directive used outside if context")
+	errConditionOutsideIfContext             = errors.New("directive used outside of if context")
+	errMissingEndif                          = errors.New("missing endif")
+	errMultipleElseFound                     = errors.New("multiple else found")
+	errReptCountNegative                     = errors.New("rept count can not be negative")
 )
 
 type expressionEvaluation struct {
@@ -55,7 +58,7 @@ func evaluateExpressionsStep(asm *Assembler) error {
 	}
 
 	if expEval.currentContext.parent != nil {
-		return errors.New("missing endif")
+		return errMissingEndif
 	}
 	return nil
 }
@@ -304,8 +307,8 @@ func parseRept(expEval *expressionEvaluation, rept ast.Rept, seg *segment, curre
 	if err != nil {
 		return fmt.Errorf("getting rept count: %w", err)
 	}
-	if count <= 0 {
-		return errors.New("rept count must be positive")
+	if count < 0 {
+		return errReptCountNegative
 	}
 
 	var nodes []ast.Node
@@ -325,22 +328,36 @@ func parseRept(expEval *expressionEvaluation, rept ast.Rept, seg *segment, curre
 		return errors.New("rept without endr found")
 	}
 
-	// insert the nodes count-1 times, as the first insertion are the existing nodes
-	count--
+	unrollReptNodes(nodes, seg, currentNodeIndex, count)
+
+	return nil
+}
+
+func unrollReptNodes(nodes []ast.Node, seg *segment, currentNodeIndex int, count int64) {
 	nodesToInsert := make([]ast.Node, 0, len(nodes)*int(count))
-	for range count {
-		for _, node := range nodes {
-			nodesToInsert = append(nodesToInsert, node.Copy())
+
+	if count > 0 {
+		// insert the nodes count-1 times, as the first insertion are the existing nodes
+		count--
+		for range count {
+			for _, node := range nodes {
+				nodesToInsert = append(nodesToInsert, node.Copy())
+			}
 		}
-	}
 
-	// copy nodes up to endr
-	nodes = seg.nodes[:currentNodeIndex+len(nodesToInsert)-1]
-	// append now node copies
-	nodes = append(nodes, nodesToInsert...)
-	// append nodes after endr
-	nodes = append(nodes, seg.nodes[currentNodeIndex+len(nodesToInsert):]...)
+		// copy nodes up to endr
+		nodes = seg.nodes[:currentNodeIndex+len(nodesToInsert)-1]
+		// append now node copies
+		nodes = append(nodes, nodesToInsert...)
+		// append nodes after endr
+		nodes = append(nodes, seg.nodes[currentNodeIndex+len(nodesToInsert):]...)
+	} else {
+		reptNodeCount := len(nodes)
+		// copy nodes up to rept
+		nodes = seg.nodes[:currentNodeIndex+1]
+		// append nodes after endr
+		nodes = append(nodes, seg.nodes[currentNodeIndex+reptNodeCount+2:]...)
+	}
 
 	seg.nodes = nodes
-	return nil
 }

go.mod

@@ -2,4 +2,4 @@ module github.com/retroenv/retroasm
 
 go 1.22
 
-require github.com/retroenv/retrogolib v0.0.0-20240320144300-4dc6a43b5983
+require github.com/retroenv/retrogolib v0.0.0-20241111003331-fc91264b5684

go.sum

@@ -1,2 +1,2 @@
-github.com/retroenv/retrogolib v0.0.0-20240320144300-4dc6a43b5983 h1:jqCLtAkseEa0cgNOvlyNjYxA0rnJzR3KG/zHeBd7Fwo=
-github.com/retroenv/retrogolib v0.0.0-20240320144300-4dc6a43b5983/go.mod h1:HZ3Y8NA+pJQrTLDJ6VSg/X6Oo4jWxz2S9ZMSvv8Zm1o=
+github.com/retroenv/retrogolib v0.0.0-20241111003331-fc91264b5684 h1:4dQQv1dgk2t1pGFpcczmKRsHuAvMxZN/fUPMwESwmjg=
+github.com/retroenv/retrogolib v0.0.0-20241111003331-fc91264b5684/go.mod h1:8pe9mEjbKL9Z5L4FFzYGSk1Ovhrq1LR6ucwRFj5CIXs=