package build

import (
	"git.akyoto.dev/cli/q/src/build/asm"
	"git.akyoto.dev/cli/q/src/build/config"
	"git.akyoto.dev/cli/q/src/build/cpu"
)

// SaveRegister attempts to move a variable occupying this register to another register.
func (f *Function) SaveRegister(register cpu.Register) {
	if f.cpu.IsFree(register) {
		return
	}

	var variable *Variable

	for _, v := range f.variables {
		if v.Register == register {
			variable = v
			break
		}
	}

	if variable == nil || variable.Alive == 0 {
		return
	}

	newRegister, exists := f.cpu.FindFree(f.cpu.General)

	if !exists {
		panic("no free registers")
	}

	if config.Verbose {
		f.Logf("moving %s from %s to %s (alive: %d)", variable.Name, variable.Register, newRegister, variable.Alive)
	}

	f.assembler.RegisterRegister(asm.MOVE, newRegister, register)
	f.cpu.Free(register)
	f.cpu.Use(newRegister)
	variable.Register = newRegister
}