package examples

import (
	"git.gammaspectra.live/WeebDataHoarder/compute-go/amd64"
	"git.gammaspectra.live/WeebDataHoarder/compute-go/assembler"
	"git.gammaspectra.live/WeebDataHoarder/compute-go/assembler/obj"
)

func Mul64() (mul func(a, b uint64) (hi, lo uint64), clean func() error, err error) {
	b, err := assembler.NewBuilder(amd64.ABIDefinition)
	if err != nil {
		return nil, nil, err
	}

	mul, clean, err = assembler.CreateFunction[func(a, b uint64) (hi, lo uint64)](b, obj.ABIInternal, "mul64",
		func(b *assembler.Builder, params []assembler.AddressableList, returns []assembler.AddressableList, regs *assembler.RegisterAllocator, data *assembler.DataAllocator) (frameSize, textFlag int, err error) {
			aReg := regs.AllocArgOutput(params[0])
			defer regs.Free(aReg)
			// this gets optimized out on ABI1
			amd64.Mov64(b, params[0].One(), aReg)
			amd64.Mov64(b, aReg, amd64.AX)
			amd64.MulUint64(b, params[1].One())

			amd64.Mov64(b, amd64.AX, returns[1].One())
			amd64.Mov64(b, amd64.DX, returns[0].One())
			amd64.Return(b)
			return 0, obj.NOFRAME | obj.NOSPLIT, nil
		},
		nil)
	if err != nil {
		return nil, nil, err
	}
	return mul, clean, nil
}