Some stuff with the script decoding

I honestly don't remember what these changes are, lol.

Makefile

@@ -1,8 +1,9 @@
 .PHONY: all
 
-COMMANDS: bin/script-decode
+all: bin/script-decode bin/sbutil
 
-all: $(COMMANDS)
-
-bin/%: cmd/%.go script/*.go
+bin/script-decode: cmd/script-decode.go script/*.go
+	go build -o $@ $<
+
+bin/sbutil: cmd/sbutil.go rom/*.go
 	go build -o $@ $<

cmd/script-decode.go

@@ -58,7 +58,7 @@ func run(args *Arguments) error {
 	fmt.Fprintf(outfile, "; Stack address: $%04X\n\n", scr.StackAddress)
 
 	for _, token := range scr.Tokens {
-		fmt.Fprintln(outfile, token)
+		fmt.Fprintln(outfile, token.String(scr.Labels))
 	}
 
 	return nil

rom/decoder.go

@@ -10,17 +10,18 @@ import (
 // Returns packet, next state, and error (if any)
 type decodeFunction func(page *Page, data []byte, startIdx int) (Packet, int, error)
 
-// map of states.  each state is a map of types
+// Map of states.  Each state is a map of types
 var definedPackets = map[int]map[byte]decodeFunction{
-	0: map[byte]decodeFunction{
+
+	0: map[byte]decodeFunction{ // state 3 in firmware.org
 		0x01: decodeHeader,
 	},
 
-	1: map[byte]decodeFunction{
+	1: map[byte]decodeFunction{ // state 1 in firmware.org
 		0x00: decodeMarkDataEnd,
 	},
 
-	2: map[byte]decodeFunction{
+	2: map[byte]decodeFunction{ // state 2 in firmware.org
 		0x02: decodeSetWorkRamLoad,
 		0x03: decodeMarkDataStart,
 		0x04: decodeMarkDataStart,
@@ -45,18 +46,19 @@ func (page *Page) decode(data []byte) error {
 			return nil
 		}
 
+		stateArg := data[idx+1]
 		var packet Packet
-		if page.state == 1 && data[idx+1] != 0x00 {
+		if page.state == 1 && stateArg != 0x00 {  // stateArg is length here?
 			// bulk data
 			packet, page.state, err = decodeBulkData(page, data, idx)
 			if err != nil {
 				return err
 			}
 		} else {
-			df, ok := definedPackets[page.state][data[idx+1]]
+			df, ok := definedPackets[page.state][stateArg]
 			if !ok {
 				return fmt.Errorf("State %d packet with type %02X isn't implemented",
-					page.state, data[idx+1])
+					page.state, stateArg)
 			}
 			packet, page.state, err = df(page, data, idx)
 			if err != nil {
@@ -149,7 +151,7 @@ func decodeMarkDataStart(page *Page, data []byte, idx int) (Packet, int, error)
 func decodeMarkDataEnd(page *Page, data []byte, idx int) (Packet, int, error) {
 	packet := &packetMarkDataEnd{
 		Type:     data[idx+2],
-		Reset:    (data[idx+2]&0xF0 == 0xF0),
+		Reset:    (data[idx+2]&0xF0 == 0xF0),  // what is this?
 		checksum: data[idx+3],
 		address:  page.DataOffset + idx,
 	}
@@ -195,6 +197,9 @@ func decodeSetWorkRamLoad(page *Page, data []byte, idx int) (Packet, int, error)
 }
 
 func decodeBulkData(page *Page, data []byte, idx int) (Packet, int, error) {
+	// idx+1: length of data
+	// idx+2: data start
+
 	if data[idx+1] == 0 {
 		return nil, 0, fmt.Errorf("Bulk data packet has a length of zero at offset %08X",
 			page.DataOffset+idx)
@@ -206,8 +211,9 @@ func decodeBulkData(page *Page, data []byte, idx int) (Packet, int, error) {
 
 	datalen := int(data[idx+1])
 	packet.Data = data[idx+2 : idx+2+datalen]
-	packet.checksum = data[idx+len(packet.Data)+2]
+	packet.checksum = data[idx+2+len(packet.Data)]
 
+	// checksum includes the packet ID and data length values
 	checksum := calcChecksum(data[idx : idx+int(data[idx+1])+2])
 	if checksum != packet.checksum {
 		data := []string{}

rom/export.go

@@ -13,6 +13,10 @@ func (sb *StudyBox) Export(directory string) error {
 		Audio:   directory + "/audio" + sb.Audio.ext(),
 	}
 
+	// A "Page" here does not correspond to the entered "Page" number on the
+	// title screen.  These are really segments.  The "Page" that is entered on
+	// the title screen is stored in the header of a segment.  Multiple
+	// segments can have the same "Page" number.
 	for pidx, page := range sb.Data.Pages {
 		jp := jsonPage{
 			AudioOffsetLeadIn: page.AudioOffsetLeadIn,
@@ -20,7 +24,7 @@ func (sb *StudyBox) Export(directory string) error {
 			Data:              []jsonData{},
 		}
 
-		file, err := os.Create(fmt.Sprintf("%s/page%02d_0000.txt", directory, pidx))
+		file, err := os.Create(fmt.Sprintf("%s/segment-%02d_packet-0000.txt", directory, pidx))
 		if err != nil {
 			return err
 		}
@@ -74,13 +78,13 @@ func (sb *StudyBox) Export(directory string) error {
 
 				switch jData.Type {
 				case "pattern":
-					jData.File = fmt.Sprintf("%s/page%02d_%04d_chrData.chr", directory, pidx, dataStartId)
+					jData.File = fmt.Sprintf("%s/segment-%02d_packet-%04d_chrData.chr", directory, pidx, dataStartId)
 
 				case "nametable":
-					jData.File = fmt.Sprintf("%s/page%02d_%04d_ntData.dat", directory, pidx, dataStartId)
+					jData.File = fmt.Sprintf("%s/segment-%02d_packet-%04d_ntData.dat", directory, pidx, dataStartId)
 
 				case "script":
-					jData.File = fmt.Sprintf("%s/page%02d_%04d_scriptData.dat", directory, pidx, dataStartId)
+					jData.File = fmt.Sprintf("%s/segment-%02d_packet-%04d_scriptData.dat", directory, pidx, dataStartId)
 
 					//script, err := DissassembleScript(scriptData)
 					//if err != nil {
@@ -118,7 +122,7 @@ func (sb *StudyBox) Export(directory string) error {
 				rawData = append(rawData, p.Data...)
 
 			default:
-				return fmt.Errorf("Encountered an unknown packet: %s page: %d", p.Asm(), pidx)
+				return fmt.Errorf("Encountered an unknown packet: %s segment: %d", p.Asm(), pidx)
 			}
 		}
 

rom/packets.go

@@ -26,7 +26,7 @@ func (ph *packetHeader) RawBytes() []byte {
 }
 
 func (ph *packetHeader) Asm() string {
-	return fmt.Sprintf("header %d ; Checksum: %02X", ph.PageNumber, ph.Checksum)
+	return fmt.Sprintf("header %d [Page %d] ; Checksum: %02X", ph.PageNumber, ph.PageNumber+1, ph.Checksum)
 }
 
 func (ph *packetHeader) Address() int {
@@ -81,7 +81,7 @@ func newPacketWorkRamLoad(bank, addressHigh uint8) *packetWorkRamLoad {
 }
 
 func (p *packetWorkRamLoad) Asm() string {
-	return fmt.Sprintf("work_ram_load $%02X $%02X ; Checksum %02X",
+	return fmt.Sprintf("work_ram_load bank:$%02X addr:$%02X00 ; Checksum %02X",
 		p.bankId, p.loadAddressHigh, p.checksum)
 }
 
@@ -192,7 +192,7 @@ func (p *packetMarkDataStart) Address() int {
 
 type packetMarkDataEnd struct {
 	//Arg   uint8
-	Reset bool
+	Reset bool // what does this mean?  what is special about the value 0xF0?
 	Type  uint8
 
 	address  int
@@ -251,7 +251,8 @@ func (p *packetMarkDataEnd) Asm() string {
 	for _, b := range p.RawBytes() {
 		s = append(s, fmt.Sprintf("%02X", b))
 	}
-	return fmt.Sprintf("mark_datatype_end %s ; %s Checksum: %02X", tstr, strings.Join(s, " "), p.checksum)
+	return fmt.Sprintf("mark_datatype_end %s ; %s Checksum: %02X",
+		tstr, strings.Join(s, " "), p.checksum)
 }
 
 func (p *packetMarkDataEnd) Address() int {

script/instructions.go

@@ -52,6 +52,8 @@ var Instructions []*Instruction = []*Instruction{
 	&Instruction{ 0x9B, 0, 0, 0,  "halt"},
 	&Instruction{ 0x9C, 0, 0, 0,  "toggle_44FE"},
 	&Instruction{ 0x9D, 2, 0, 0,  "something_tape"},
+
+	// Calls 0xEB draw_overlay.  Seems to draw a whole screen.
 	&Instruction{ 0x9E, 2, 0, 0,  ""},
 	&Instruction{ 0x9F, 6, 0, 0,  ""},
 
@@ -135,7 +137,14 @@ var Instructions []*Instruction = []*Instruction{
 	&Instruction{ 0xDA, 1, 0, 16, "to_int_string"},
 	&Instruction{ 0xDB, 3, 0, 0,  ""},
 	&Instruction{ 0xDC, 5, 0, 0,  ""},
-	&Instruction{ 0xDD, 5, 0, 0,  ""},
+
+	// ArgA, ArgB: X,Y of corner A
+	// ArgC, ArgD: X,Y of corner B
+	// ArgE: fill value.  This is an index into
+	//       the table at $B451.
+	// Fills a box with a tile
+	&Instruction{ 0xDD, 5, 0, 0,  "fill_box"},
+
 	&Instruction{ 0xDE, 3, 0, 0,  ""},
 	&Instruction{ 0xDF, 3, 0, 0,  ""},
 
@@ -153,7 +162,14 @@ var Instructions []*Instruction = []*Instruction{
 	&Instruction{ 0xE8, 1, 0, 0,  "setup_tape_nmi"},
 	&Instruction{ 0xE9, 0, 1, 0,  "setup_loop"},
 	&Instruction{ 0xEA, 0, 0, 0,  "string_write_to_table"},
-	&Instruction{ 0xEB, 4, 0, 0,  ""},
+
+	// Reads and saves tiles from the PPU, then draws over them.
+	// This is used to draw dialog boxes, so saving what it overwrites
+	// so it can re-draw them later makes sense.
+	// Not sure what the arguments actually mean.
+	// ArgB and ArgC are probably coordinates.
+	&Instruction{ 0xEB, 4, 0, 0,  "draw_overlay"},
+
 	&Instruction{ 0xEC, 2, 0, 0,  "scroll"},
 	&Instruction{ 0xED, 1, 0, 0,  "disable_sprites"},
 	&Instruction{ 0xEE, 1, -3, 0, "call_switch"},

script/parser.go

@@ -24,7 +24,9 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 		Warnings: []string{},
 		StackAddress: (int(rawinput[1])<<8) | int(rawinput[0]),
 		StartAddress: startAddr,
+		Labels: make(map[int]string), // map[location]name
 	}
+	tokenMap := make(map[int]*Token)
 
 	for i := 2; i < len(rawinput); i++ {
 		raw := rawinput[i]
@@ -35,6 +37,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 			Inline: []InlineVal{},
 		}
 		script.Tokens = append(script.Tokens, token)
+		tokenMap[token.Offset] = token
 
 		if raw < 0x80 {
 			continue
@@ -102,6 +105,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 				if tok.Offset == addr {
 					tok.IsTarget = true
 					found = true
+					script.Labels[addr] = fmt.Sprintf("L%04X", addr)
 					break
 				}
 			}
@@ -122,6 +126,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 					if tok.Offset == addr {
 						tok.IsTarget = true
 						found = true
+						script.Labels[addr] = fmt.Sprintf("L%04X", addr)
 						break
 					}
 				}
@@ -130,6 +135,19 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 					script.Warnings = append(script.Warnings, fmt.Sprintf("Warning: no target found for jump/call switch at offset $%04X; value: $%04X", t.Offset, addr))
 				}
 			}
+
+		default:
+			// if word arg, see if it's something in this script
+			if t.Instruction == nil {
+				continue
+			}
+			if t.Instruction.OpCount == 2 {
+				addr := t.Inline[0].Int()
+				if tok, ok := tokenMap[addr]; ok {
+					tok.IsVariable = true
+					script.Labels[addr] = fmt.Sprintf("Var_%04X", addr)
+				}
+			}
 		}
 	}
 

script/script.go

@@ -9,4 +9,6 @@ type Script struct {
 
 	StartAddress int
 	StackAddress int
+
+	Labels map[int]string
 }

script/tokens.go

@@ -10,11 +10,12 @@ type Token struct {
 	Raw      byte
 	Inline   []InlineVal
 	IsTarget bool   // target of a call/jump?
+	IsVariable bool // target of something else
 
 	Instruction *Instruction
 }
 
-func (t Token) String() string {
+func (t Token) String(labels map[int]string) string {
 	suffix := ""
 	switch t.Raw {
 	case 0x86:
@@ -22,9 +23,13 @@ func (t Token) String() string {
 	}
 
 	prefix := ""
-	if t.IsTarget {
+	if t.IsTarget || t.IsVariable {
+		if lbl, ok := labels[t.Offset]; ok {
+			prefix = "\n"+lbl+":\n"
+		} else {
 			prefix = fmt.Sprintf("\nL%04X:\n", t.Offset)
 		}
+	}
 
 	if t.Raw < 0x80 {
 		return fmt.Sprintf("%s[%04X] %02X %-5s : %d%s",
@@ -50,18 +55,26 @@ func (t Token) String() string {
 
 	argstr := []string{}
 	for _, a := range t.Inline {
+		if lbl, ok := labels[a.Int()]; ok {
+			argstr = append(argstr, lbl)
+		} else {
 			argstr = append(argstr, a.HexString())
 		}
+	}
 
 	bytestr := []string{}
 	for _, a := range t.Inline {
 		for _, b := range a.Bytes() {
+			//if lbl, ok := labels[a.Int()]; ok {
+			//	bytestr = append(bytestr, lbl)
+			//} else {
 				bytestr = append(bytestr, fmt.Sprintf("%02X", b))
+			//}
 		}
 	}
 
 	switch t.Raw {
-	case 0xBB:
+	case 0xBB: // push_data
 		bs := []byte{}
 		for _, val := range t.Inline {
 			bs = append(bs, val.Bytes()...)