138 lines
2.8 KiB
Go
138 lines
2.8 KiB
Go
package script
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import (
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"fmt"
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"os"
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)
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func ParseFile(filename string, startAddr int) (*Script, error) {
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rawfile, err := os.ReadFile(filename)
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if err != nil {
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return nil, fmt.Errorf("unable to read file: %w", err)
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}
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return Parse(rawfile, startAddr)
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}
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func Parse(rawinput []byte, startAddr int) (*Script, error) {
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if len(rawinput) < 3 {
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return nil, fmt.Errorf("not enough bytes for script")
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}
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script := &Script{
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Tokens: []*Token{},
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Warnings: []string{},
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StackAddress: (int(rawinput[1])<<8) | int(rawinput[0]),
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StartAddress: startAddr,
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}
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for i := 2; i < len(rawinput); i++ {
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raw := rawinput[i]
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token := &Token{
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Offset: startAddr+i,
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Raw: raw,
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Inline: []InlineVal{},
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}
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script.Tokens = append(script.Tokens, token)
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if raw < 0x80 {
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continue
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}
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op, ok := InstrMap[raw]
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if !ok {
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return nil, fmt.Errorf("OP %02X not in instruction map", raw)
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}
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token.Instruction = op
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args := []InlineVal{}
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switch op.OpCount {
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case -1: // null terminated
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for ; i < len(rawinput); i++ {
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val := ByteVal(rawinput[i])
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args = append(args, val)
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if rawinput[i] == 0x00 {
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break
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}
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}
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case -2: // count then count words
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i++
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l := int(rawinput[i])
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args = append(args, ByteVal(l))
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i++
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for c := 0; c < l; c++ {
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args = append(args, WordVal([2]byte{rawinput[i], rawinput[i+1]}))
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i+=2
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}
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case -3: // count then count+1 words (extra is default case)
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i++
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l := int(rawinput[i])
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args = append(args, ByteVal(l))
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i++
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for c := 0; c < l+1; c++ {
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args = append(args, WordVal([2]byte{rawinput[i], rawinput[i+1]}))
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i+=2
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}
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case 2:
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args = append(args, WordVal([2]byte{rawinput[i+1], rawinput[i+2]}))
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i+=2
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case 1:
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i++
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args = append(args, ByteVal(rawinput[i]))
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}
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token.Inline = args
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}
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for _, t := range script.Tokens {
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switch t.Raw {
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case 0x84, 0x85, 0xBF, 0xC0: // jmp/call
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if len(t.Inline) == 0 {
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return nil, fmt.Errorf("jump/call missing address")
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}
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addr := t.Inline[0].Int()
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found := false
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for _, tok := range script.Tokens {
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if tok.Offset == addr {
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tok.IsTarget = true
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found = true
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break
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}
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}
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if !found {
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script.Warnings = append(script.Warnings, fmt.Sprintf("Warning: no target found for jump/call at offset $%04X; value $%04X", t.Offset, addr))
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}
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case 0xC1, 0xEE: // switches
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if len(t.Inline) < 2 {
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return nil, fmt.Errorf("jump/call switch missing addresses")
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}
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for _, v := range t.Inline[1:] {
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addr := v.Int()
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found := false
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for _, tok := range script.Tokens {
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if tok.Offset == addr {
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tok.IsTarget = true
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found = true
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break
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}
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}
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if !found {
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script.Warnings = append(script.Warnings, fmt.Sprintf("Warning: no target found for jump/call switch at offset $%04X; value: $%04X", t.Offset, addr))
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}
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}
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}
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}
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return script, nil
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}
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