454 lines
12 KiB
Go
454 lines
12 KiB
Go
package commands
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import (
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"fmt"
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"os"
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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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// ShiftLCommand handles logical shift left operations
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// Syntax:
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//
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// SHIFTL <source> BY <amount> GIVING <dest> # old syntax with BY/GIVING
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// SHIFTL <source> << <amount> -> <dest> # old syntax with <</->
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// <dest> = <source> << <amount> # new syntax
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type ShiftLCommand struct {
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sourceVarName string
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sourceVarKind compiler.VarKind
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sourceValue uint16
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sourceIsVar bool
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amountVarName string
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amountVarKind compiler.VarKind
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amountValue uint16
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amountIsVar bool
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destVarName string
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destVarKind compiler.VarKind
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line preproc.Line // Store line info for warnings
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}
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func (c *ShiftLCommand) 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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// Old syntax: SHIFTL ... (must have exactly 6 params)
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if strings.ToUpper(params[0]) == "SHIFTL" && len(params) == 6 {
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return true
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}
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// New syntax: <dest> = <source> << <amount>
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if len(params) == 5 && params[1] == "=" && params[3] == "<<" {
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return true
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}
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return false
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}
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func (c *ShiftLCommand) Interpret(line preproc.Line, ctx *compiler.CompilerContext) error {
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// Clear state
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c.sourceVarName = ""
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c.sourceIsVar = false
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c.sourceValue = 0
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c.amountVarName = ""
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c.amountIsVar = false
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c.amountValue = 0
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c.destVarName = ""
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c.line = line // Store line for warnings
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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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paramCount := len(params)
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scope := ctx.CurrentScope()
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// Create constant lookup function
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constLookup := ctx.SymbolTable.ConstantLookupFunc(scope)
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// Determine syntax and parse accordingly
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if strings.ToUpper(params[0]) == "SHIFTL" {
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// Old syntax: SHIFTL <source> BY/<< <amount> GIVING/-> <dest>
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if paramCount != 6 {
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return fmt.Errorf("SHIFTL: wrong number of parameters (%d), expected 6", paramCount)
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}
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separator1 := strings.ToUpper(params[2])
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if separator1 != "BY" && separator1 != "<<" {
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return fmt.Errorf("SHIFTL: parameter #3 must be 'BY' or '<<', got %q", params[2])
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}
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separator2 := strings.ToUpper(params[4])
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if separator2 != "GIVING" && separator2 != "->" {
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return fmt.Errorf("SHIFTL: parameter #5 must be 'GIVING' or '->', got %q", params[4])
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}
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// Parse destination
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destName := params[5]
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destSym := ctx.SymbolTable.Lookup(destName, scope)
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if destSym == nil {
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return fmt.Errorf("SHIFTL: unknown variable %q", destName)
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}
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if destSym.IsConst() {
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return fmt.Errorf("SHIFTL: cannot assign to constant %q", destName)
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}
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c.destVarName = destSym.FullName()
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c.destVarKind = destSym.GetVarKind()
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// Parse source
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var err error
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c.sourceVarName, c.sourceVarKind, c.sourceValue, c.sourceIsVar, err = compiler.ParseOperandParam(
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params[1], ctx.SymbolTable, scope, constLookup)
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if err != nil {
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return fmt.Errorf("SHIFTL: source: %w", err)
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}
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// Parse amount
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c.amountVarName, c.amountVarKind, c.amountValue, c.amountIsVar, err = compiler.ParseOperandParam(
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params[3], ctx.SymbolTable, scope, constLookup)
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if err != nil {
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return fmt.Errorf("SHIFTL: amount: %w", err)
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}
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} else {
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// New syntax: <dest> = <source> << <amount>
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if paramCount != 5 {
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return fmt.Errorf("SHIFTL: wrong number of parameters (%d), expected 5", paramCount)
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}
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if params[1] != "=" {
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return fmt.Errorf("SHIFTL: expected '=' at position 2, got %q", params[1])
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}
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if params[3] != "<<" {
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return fmt.Errorf("SHIFTL: expected '<<' at position 4, got %q", params[3])
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}
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// Parse destination
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destName := params[0]
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destSym := ctx.SymbolTable.Lookup(destName, scope)
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if destSym == nil {
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return fmt.Errorf("SHIFTL: unknown variable %q", destName)
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}
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if destSym.IsConst() {
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return fmt.Errorf("SHIFTL: cannot assign to constant %q", destName)
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}
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c.destVarName = destSym.FullName()
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c.destVarKind = destSym.GetVarKind()
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// Parse source
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var err error
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c.sourceVarName, c.sourceVarKind, c.sourceValue, c.sourceIsVar, err = compiler.ParseOperandParam(
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params[2], ctx.SymbolTable, scope, constLookup)
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if err != nil {
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return fmt.Errorf("SHIFTL: source: %w", err)
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}
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// Parse amount
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c.amountVarName, c.amountVarKind, c.amountValue, c.amountIsVar, err = compiler.ParseOperandParam(
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params[4], ctx.SymbolTable, scope, constLookup)
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if err != nil {
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return fmt.Errorf("SHIFTL: amount: %w", err)
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}
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}
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// Validate amount
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if c.amountIsVar {
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if c.amountVarKind == compiler.KindWord {
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return fmt.Errorf("SHIFTL: amount must be BYTE variable, got WORD %q", c.amountVarName)
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}
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} else {
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if c.amountValue > 255 {
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return fmt.Errorf("SHIFTL: amount constant %d out of BYTE range (0-255)", c.amountValue)
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}
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}
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return nil
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}
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func (c *ShiftLCommand) Generate(ctx *compiler.CompilerContext) ([]string, error) {
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// Case 1: BYTE destination
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if c.destVarKind == compiler.KindByte {
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return c.generateByteShift(ctx)
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}
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// Case 2: WORD destination
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return c.generateWordShift(ctx)
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}
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// generateByteShift handles BYTE << amount
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func (c *ShiftLCommand) generateByteShift(ctx *compiler.CompilerContext) ([]string, error) {
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var asm []string
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// Constant shift amount
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if !c.amountIsVar {
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amount := c.amountValue
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// Shift >= 8 bits -> zero
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if amount >= 8 {
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if amount > 0 {
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_, _ = fmt.Fprintf(os.Stderr, "%s:%d: warning: shift amount %d >= 8 bits, value will be zero\n",
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c.line.Filename, c.line.LineNo, amount)
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}
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// Store zero
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if c.sourceIsVar && c.sourceVarName == c.destVarName {
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// Same variable: just zero it
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asm = append(asm, "\tlda #0")
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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} else {
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// Different: load zero and store
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asm = append(asm, "\tlda #0")
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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}
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return asm, nil
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}
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// Shift 0 -> copy source
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if amount == 0 {
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return c.generateByteCopy(), nil
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}
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// Constant shift 1-7
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return c.generateByteShiftConst(amount), nil
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}
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// Variable shift amount
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return c.generateByteShiftVar(ctx)
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}
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// generateByteCopy copies source to destination (BYTE)
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func (c *ShiftLCommand) generateByteCopy() []string {
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var asm []string
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if c.sourceIsVar {
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if c.sourceVarName == c.destVarName {
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// Same variable, no copy needed
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return asm
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}
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// Different variable
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asm = append(asm, fmt.Sprintf("\tlda %s", c.sourceVarName))
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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} else {
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// Literal
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val := uint8(c.sourceValue & 0xFF)
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asm = append(asm, fmt.Sprintf("\tlda #$%02x", val))
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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}
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return asm
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}
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// generateByteShiftConst generates BYTE << constant (1-7)
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func (c *ShiftLCommand) generateByteShiftConst(amount uint16) []string {
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var asm []string
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// Copy source to destination if needed
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copyAsm := c.generateByteCopy()
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asm = append(asm, copyAsm...)
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// Apply shift
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for i := uint16(0); i < amount; i++ {
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asm = append(asm, fmt.Sprintf("\tasl %s", c.destVarName))
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}
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return asm
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}
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// generateByteShiftVar generates BYTE << variable
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func (c *ShiftLCommand) generateByteShiftVar(ctx *compiler.CompilerContext) ([]string, error) {
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var asm []string
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// Copy source to destination if needed
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copyAsm := c.generateByteCopy()
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asm = append(asm, copyAsm...)
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// Generate labels
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loopLabel := ctx.GeneralStack.Push()
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ctx.GeneralStack.Pop()
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doneLabel := ctx.GeneralStack.Push()
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ctx.GeneralStack.Pop()
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// Variable shift loop
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asm = append(asm, fmt.Sprintf("\tldx %s", c.amountVarName))
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asm = append(asm, fmt.Sprintf("\tbeq %s", doneLabel))
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asm = append(asm, loopLabel)
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asm = append(asm, fmt.Sprintf("\tasl %s", c.destVarName))
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asm = append(asm, "\tdex")
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asm = append(asm, fmt.Sprintf("\tbne %s", loopLabel))
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asm = append(asm, doneLabel)
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return asm, nil
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}
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// generateWordShift handles WORD << amount
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func (c *ShiftLCommand) generateWordShift(ctx *compiler.CompilerContext) ([]string, error) {
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// Constant shift amount
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if !c.amountIsVar {
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amount := c.amountValue
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// Shift >= 16 bits -> zero
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if amount >= 16 {
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if amount > 0 {
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_, _ = fmt.Fprintf(os.Stderr, "%s:%d: warning: shift amount %d >= 16 bits, value will be zero\n",
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c.line.Filename, c.line.LineNo, amount)
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}
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// Store zero
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if c.sourceIsVar && c.sourceVarName == c.destVarName {
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// Same variable: zero both bytes
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asm := []string{
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"\tlda #0",
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fmt.Sprintf("\tsta %s", c.destVarName),
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fmt.Sprintf("\tsta %s+1", c.destVarName),
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}
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return asm, nil
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} else {
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// Different: load zero and store to both bytes
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asm := []string{
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"\tlda #0",
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fmt.Sprintf("\tsta %s", c.destVarName),
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fmt.Sprintf("\tsta %s+1", c.destVarName),
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}
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return asm, nil
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}
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}
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// Shift 0 -> copy source
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if amount == 0 {
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return c.generateWordCopy(), nil
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}
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// Constant shift 1-15
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return c.generateWordShiftConst(amount), nil
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}
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// Variable shift amount
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return c.generateWordShiftVar(ctx)
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}
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// generateWordCopy copies source to destination (WORD)
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func (c *ShiftLCommand) generateWordCopy() []string {
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var asm []string
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if c.sourceIsVar && c.sourceVarName == c.destVarName {
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// Same variable, no copy needed
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return asm
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}
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if c.sourceIsVar {
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// Variable source
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if c.sourceVarKind == compiler.KindByte {
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// Byte -> Word (zero-extend)
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asm = append(asm, fmt.Sprintf("\tlda %s", c.sourceVarName))
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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asm = append(asm, "\tlda #0")
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asm = append(asm, fmt.Sprintf("\tsta %s+1", c.destVarName))
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} else {
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// Word -> Word
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asm = append(asm, fmt.Sprintf("\tlda %s", c.sourceVarName))
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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asm = append(asm, fmt.Sprintf("\tlda %s+1", c.sourceVarName))
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asm = append(asm, fmt.Sprintf("\tsta %s+1", c.destVarName))
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}
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} else {
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// Literal source
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lo := uint8(c.sourceValue & 0xFF)
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hi := uint8((c.sourceValue >> 8) & 0xFF)
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asm = append(asm, fmt.Sprintf("\tlda #$%02x", lo))
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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if lo != hi {
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asm = append(asm, fmt.Sprintf("\tlda #$%02x", hi))
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}
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asm = append(asm, fmt.Sprintf("\tsta %s+1", c.destVarName))
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}
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return asm
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}
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// generateWordShiftConst generates WORD << constant (1-15)
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func (c *ShiftLCommand) generateWordShiftConst(amount uint16) []string {
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var asm []string
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// Special case: shift >= 8
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if amount >= 8 && amount < 16 {
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remaining := amount - 8
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// Get source low byte
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if c.sourceIsVar {
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if c.sourceVarName == c.destVarName {
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// Same variable: read from destination (already has value)
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asm = append(asm, fmt.Sprintf("\tlda %s", c.destVarName))
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} else {
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// Different: read from source
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asm = append(asm, fmt.Sprintf("\tlda %s", c.sourceVarName))
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}
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} else {
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// Literal
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lo := uint8(c.sourceValue & 0xFF)
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asm = append(asm, fmt.Sprintf("\tlda #$%02x", lo))
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}
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// Store to destination high byte
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asm = append(asm, fmt.Sprintf("\tsta %s+1", c.destVarName))
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// Zero low byte
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asm = append(asm, "\tlda #0")
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asm = append(asm, fmt.Sprintf("\tsta %s", c.destVarName))
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// Shift high byte remaining bits
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for i := uint16(0); i < remaining; i++ {
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asm = append(asm, fmt.Sprintf("\tasl %s+1", c.destVarName))
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}
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return asm
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}
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// Shift 1-7: normal copy and shift
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copyAsm := c.generateWordCopy()
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asm = append(asm, copyAsm...)
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// Apply shift
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for i := uint16(0); i < amount; i++ {
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asm = append(asm, fmt.Sprintf("\tasl %s", c.destVarName))
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asm = append(asm, fmt.Sprintf("\trol %s+1", c.destVarName))
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}
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return asm
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}
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// generateWordShiftVar generates WORD << variable
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func (c *ShiftLCommand) generateWordShiftVar(ctx *compiler.CompilerContext) ([]string, error) {
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var asm []string
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// Copy source to destination if needed
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copyAsm := c.generateWordCopy()
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asm = append(asm, copyAsm...)
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// Generate labels
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loopLabel := ctx.GeneralStack.Push()
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ctx.GeneralStack.Pop()
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doneLabel := ctx.GeneralStack.Push()
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ctx.GeneralStack.Pop()
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// Variable shift loop
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asm = append(asm, fmt.Sprintf("\tldx %s", c.amountVarName))
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asm = append(asm, fmt.Sprintf("\tbeq %s", doneLabel))
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asm = append(asm, loopLabel)
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asm = append(asm, fmt.Sprintf("\tasl %s", c.destVarName))
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asm = append(asm, fmt.Sprintf("\trol %s+1", c.destVarName))
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asm = append(asm, "\tdex")
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asm = append(asm, fmt.Sprintf("\tbne %s", loopLabel))
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asm = append(asm, doneLabel)
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return asm, nil
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}
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