45 lines
1.2 KiB
Go
45 lines
1.2 KiB
Go
// 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
|
|
}
|