62 lines
1.5 KiB
Go
62 lines
1.5 KiB
Go
package commands
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import (
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"fmt"
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"strings"
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"c65gm/internal/compiler"
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"c65gm/internal/preproc"
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"c65gm/internal/utils"
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)
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// OriginCommand handles ORIGIN declarations
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// Syntax: ORIGIN <address>
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// Sets the assembly origin address (ACME: *= address)
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type OriginCommand struct {
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address uint16
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}
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func (c *OriginCommand) WillHandle(line preproc.Line) bool {
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params, err := utils.ParseParams(line.Text)
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if err != nil || len(params) == 0 {
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return false
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}
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upper := strings.ToUpper(params[0])
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return upper == "ORIGIN" || upper == "ORGIN" // Support common typo
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}
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func (c *OriginCommand) Interpret(line preproc.Line, ctx *compiler.CompilerContext) error {
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params, err := utils.ParseParams(line.Text)
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if err != nil {
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return err
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}
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if len(params) != 2 {
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return fmt.Errorf("ORIGIN: expected 2 parameters, got %d", len(params))
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}
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scope := ctx.CurrentScope()
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constLookup := func(name string) (int64, bool) {
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sym := ctx.SymbolTable.Lookup(name, scope)
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if sym != nil && sym.IsConst() {
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return int64(sym.Value), true
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}
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return 0, false
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}
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val, err := utils.EvaluateExpression(params[1], constLookup)
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if err != nil {
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return fmt.Errorf("ORIGIN: invalid address expression: %w", err)
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}
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if val < 0 || val > 65535 {
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return fmt.Errorf("ORIGIN: address %d out of range (0-65535)", val)
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}
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c.address = uint16(val)
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return nil
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}
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func (c *OriginCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
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return []string{fmt.Sprintf("*= $%04x", c.address)}, nil
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}
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