Add label offset + allow to use labels with .DB macro + relative labels

4 files changed, 96 insertions, 18 deletions

diff --git a/instructions.go b/instructions.go
index 59daa3a..ddcb833 100644
--- a/instructions.go
+++ b/instructions.go
@@ -8,10 +8,11 @@ import (
 type ParamType func(labels *Labels, defs *Definitions, param string) (uint16, error)
 
 type InstructionParams struct {
-	Types          []ParamType
-	Assembler      func(currentAddress uint16, args []uint16) ([]uint8, error)
-	Wildcard       bool
-	MacroForbidden bool
+	Types            []ParamType
+	Assembler        func(currentAddress uint16, args []uint16) ([]uint8, error)
+	Wildcard         bool
+	MacroForbidden   bool
+	LabelsBeforeOnly bool
 }
 
 type InstructionSet map[string][]InstructionParams
@@ -503,6 +504,7 @@ func (set InstructionSet) Parse(
 	labels *Labels,
 	defs *Definitions,
 	isMacro bool,
+	isFirstPass bool,
 	currentAddress uint16,
 	line string,
 ) ([]byte, error) {
@@ -534,7 +536,12 @@ instruction_param_loop:
 				paramType = instrParam.Types[i]
 			}
 
-			parsed, err := paramType(labels, defs, params[i])
+			accessibleLabels := labels
+
+			if isFirstPass && !instrParam.LabelsBeforeOnly {
+				accessibleLabels = nil
+			}
+			parsed, err := paramType(accessibleLabels, defs, params[i])
 			if err != nil {
 				continue instruction_param_loop
 			}
diff --git a/macros.go b/macros.go
index 8e8d4c1..5daf3c9 100644
--- a/macros.go
+++ b/macros.go
@@ -30,7 +30,16 @@ func NewInstructionSetMacros() InstructionSet {
 			Assembler: func(currentAddress uint16, args []uint16) ([]byte, error) {
 				return make([]byte, args[0]-currentAddress), nil
 			},
-			MacroForbidden: true,
+			MacroForbidden:   true,
+			LabelsBeforeOnly: true,
+		},
+		{
+			Types: []ParamType{Raw16MacroRelativeLabel},
+			Assembler: func(currentAddress uint16, args []uint16) ([]byte, error) {
+				return make([]byte, args[0]-currentAddress), nil
+			},
+			MacroForbidden:   false,
+			LabelsBeforeOnly: true,
 		},
 	}
 
@@ -46,6 +55,18 @@ func NewInstructionSetMacros() InstructionSet {
 			},
 			Wildcard: true,
 		},
+		{
+			Types: []ParamType{Raw16},
+			Assembler: func(currentAddress uint16, args []uint16) ([]byte, error) {
+				result := make([]byte, len(args)*2)
+				for i := range args {
+					result[i*2] = uint8(args[i] >> 8)
+					result[i*2+1] = uint8(args[i] & 0xff)
+				}
+				return result, nil
+			},
+			Wildcard: true,
+		},
 	}
 
 	return result
@@ -63,8 +84,8 @@ func MacroParse(
 	lines []string,
 	result *[]byte,
 	state *ProgramState,
-	line_nb *int, // line_nb
-	is_first_pass bool,
+	lineNb *int,
+	isFirstPass bool,
 	offset uint,
 ) error {
 	words := strings.Split(line, " ")
@@ -79,6 +100,7 @@ func MacroParse(
 			&state.Labels,
 			&state.Defs,
 			state.IsMacro,
+			isFirstPass,
 			uint16(uint(len(*result))+offset),
 			line,
 		)
@@ -102,7 +124,7 @@ func MacroParse(
 		}
 
 		fileStartOffset := uint(len(*result)) + offset
-		if is_first_pass {
+		if isFirstPass {
 			included, err := firstPass(filePath, input, fileStartOffset, state)
 			if err != nil {
 				return err
@@ -145,14 +167,14 @@ func MacroParse(
 			return fmt.Errorf(".MACRODEF should have one argument, followed by the definition")
 		}
 		definedMacroName := strings.ToUpper(words[1])
-		(*line_nb) += 1
+		(*lineNb) += 1
 		macroContent := []byte{}
-		for *line_nb < len(lines) && strings.TrimSpace(strings.Split(lines[*line_nb], ";")[0]) != ".END" {
-			macroContent = append(macroContent, (lines[*line_nb] + "\n")...)
-			(*line_nb) += 1
+		for *lineNb < len(lines) && strings.TrimSpace(strings.Split(lines[*lineNb], ";")[0]) != ".END" {
+			macroContent = append(macroContent, (lines[*lineNb] + "\n")...)
+			(*lineNb) += 1
 		}
 
-		if is_first_pass {
+		if isFirstPass {
 			if _, ok := MacroInstructions[definedMacroName]; ok {
 				return fmt.Errorf("Macro %s is already defined", definedMacroName)
 			}
diff --git a/main.go b/main.go
index cf087f3..dd6ce6c 100644
--- a/main.go
+++ b/main.go
@@ -43,6 +43,7 @@ func firstPass(
 
 	line_nb := 0
 	result := []byte{}
+	lastAbsoluteLabel := ""
 	for line_nb < len(lines) {
 		line := lines[line_nb]
 		line_parts := strings.Split(line, ";")
@@ -62,6 +63,25 @@ func firstPass(
 						label,
 					)
 				}
+
+				if strings.HasPrefix(label, ".") {
+					if lastAbsoluteLabel == "" {
+						return nil, fmt.Errorf(
+							"Relative label \"%s\" found without a parent",
+							label,
+						)
+					}
+
+					label = lastAbsoluteLabel + label
+				} else {
+					labelParts := strings.Split(label, ".")
+					if len(labelParts) < 1 {
+						return nil, fmt.Errorf("Unknown issue while retrieving label absolute part ! (label: \"%s\")", label)
+					}
+
+					lastAbsoluteLabel = labelParts[0]
+				}
+
 				if _, ok := state.Labels[label]; ok {
 					return nil, fmt.Errorf(
 						"File %s, line %d:\nLabel %s is already defined",
@@ -98,7 +118,7 @@ func firstPass(
 				)
 			}
 		} else {
-			next_instruction, err := Instructions.Parse(nil, &state.Defs, state.IsMacro, 0, line)
+			next_instruction, err := Instructions.Parse(&state.Labels, &state.Defs, state.IsMacro, true, 0, line)
 			if err != nil {
 				return nil, fmt.Errorf(
 					"File %s, line %d (1st pass):\n%w",
@@ -151,7 +171,7 @@ func secondPass(
 				)
 			}
 		} else {
-			next_instruction, err := Instructions.Parse(&state.Labels, &state.Defs, state.IsMacro, uint16(uint(len(result))+offset), line)
+			next_instruction, err := Instructions.Parse(&state.Labels, &state.Defs, state.IsMacro, false, uint16(uint(len(result))+offset), line)
 			if err != nil {
 				return nil, fmt.Errorf(
 					"File %s, line %d (2nd pass): %w",
diff --git a/parameters.go b/parameters.go
index 4c787f3..ddb4532 100644
--- a/parameters.go
+++ b/parameters.go
@@ -121,11 +121,30 @@ func Raw16(labels *Labels, defs *Definitions, param string) (uint16, error) {
 	}
 
 	if strings.HasPrefix(param, "=") {
+		var offset uint16 = 0
+		labelWithoutOffset := param
+
+		if strings.Contains(param, "+") {
+			labelParts := strings.Split(param, "+")
+			if len(labelParts) != 2 {
+				return 0, fmt.Errorf(
+					"Labels with offset should have exactly 1 offset (in \"%s\")",
+					param,
+				)
+			}
+			labelWithoutOffset = labelParts[0]
+			o, err := strconv.ParseUint(labelParts[1], 0, 16)
+			if err != nil {
+				return 0, fmt.Errorf("Error while parsing label offset: %w", err)
+			}
+			offset = uint16(o)
+		}
+
 		if labels == nil {
 			return 0, nil
 		}
 
-		label := strings.ToUpper(strings.TrimPrefix(param, "="))
+		label := strings.ToUpper(strings.TrimPrefix(labelWithoutOffset, "="))
 		labelValue, ok := (*labels)[label]
 		if !ok {
 			return 0, fmt.Errorf("Label \"%s\" not found", label)
@@ -136,7 +155,7 @@ func Raw16(labels *Labels, defs *Definitions, param string) (uint16, error) {
 			panic("Switchable ROM banks are not implemented yet")
 		}
 
-		return uint16(labelValue), nil
+		return uint16(labelValue) + offset, nil
 	}
 
 	res, err := strconv.ParseUint(param, 0, 16)
@@ -144,6 +163,16 @@ func Raw16(labels *Labels, defs *Definitions, param string) (uint16, error) {
 	return uint16(res), err
 }
 
+func Raw16MacroRelativeLabel(labels *Labels, defs *Definitions, param string) (uint16, error) {
+	if !strings.HasPrefix(param, "=$") {
+		return 0, fmt.Errorf(
+			"label \"%s\" is external to the macro",
+			param,
+		)
+	}
+	return Raw16(labels, defs, param)
+}
+
 func Reg16Indirect(_ *Labels, _ *Definitions, param string) (uint16, error) {
 	switch param {
 	case "(BC)":