// Copyright 2017 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package x86 // argListMax specifies upper arg count limit expected to be carried by obj.Prog. // Max len(obj.Prog.RestArgs) can be inferred from this to be 4. const argListMax int = 6 type argList [argListMax]uint8 type ytab struct { zcase uint8 zoffset uint8 // Last arg is usually destination. // For unary instructions unaryDst is used to determine // if single argument is a source or destination. args argList } // Returns true if yt is compatible with args. // // Elements from args and yt.args are used // to index ycover table like `ycover[args[i]+yt.args[i]]`. // This means that args should contain values that already // multiplied by Ymax. func (yt *ytab) match(args []int) bool { // Trailing Yxxx check is required to avoid a case // where shorter arg list is matched. // If we had exact yt.args length, it could be `yt.argc != len(args)`. if len(args) < len(yt.args) && yt.args[len(args)] != Yxxx { return false } for i := range args { if ycover[args[i]+int(yt.args[i])] == 0 { return false } } return true }