53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
package core
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import (
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"git.akyoto.dev/cli/q/src/build/asm"
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"git.akyoto.dev/cli/q/src/build/expression"
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)
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// CompileCall executes a function call.
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// All call registers must hold the correct parameter values before the function invocation.
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// Registers that are in use must be saved if they are modified by the function.
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// After the function call, they must be restored in reverse order.
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func (f *Function) CompileCall(root *expression.Expression) error {
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funcName := root.Children[0].Token.Text()
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parameters := root.Children[1:]
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registers := f.cpu.Input[:len(parameters)]
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isSyscall := funcName == "syscall"
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if isSyscall {
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registers = f.cpu.Syscall[:len(parameters)]
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}
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err := f.ExpressionsToRegisters(parameters, registers)
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if err != nil {
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return err
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}
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// Push
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for _, register := range f.cpu.General {
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if !f.cpu.IsFree(register) {
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f.assembler.Register(asm.PUSH, register)
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}
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}
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// Call
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if isSyscall {
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f.assembler.Syscall()
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} else {
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f.assembler.Call(funcName)
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}
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// Pop
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for i := len(f.cpu.General) - 1; i >= 0; i-- {
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register := f.cpu.General[i]
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if !f.cpu.IsFree(register) {
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f.assembler.Register(asm.POP, register)
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}
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}
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return nil
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}
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