/
asm.go
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/
asm.go
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// This file is part of ngaro - https://github.com/db47h/ngaro
//
// Copyright 2016 Denis Bernard <[email protected]>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package asm
import (
"io"
"strconv"
"github.com/db47h/ngaro/vm"
)
var opcodes = [...][]string{
{"nop"},
{"lit"},
{"dup"},
{"drop"},
{"swap"},
{"push"},
{"pop"},
{"loop"},
{"jump", "jmp"},
{";", "ret"},
{">jump", "jgt"},
{"<jump", "jlt"},
{"!jump", "jne"},
{"=jump", "jeq"},
{"@"},
{"!"},
{"+", "add"},
{"-", "sub"},
{"*", "mul"},
{"/mod"},
{"and"},
{"or"},
{"xor"},
{"<<", "shl"},
{">>", "asr"},
{"0;", "0ret"},
{"1+", "inc"},
{"1-", "dec"},
{"in"},
{"out"},
{"wait"},
}
// Assemble compiles assembly read from the supplied io.Reader and returns the
// resulting image and error if any.
//
// Then name parameter is used only in error messages to name the source of the
// error. If the io.Reader is a file, name should be the file name.
//
// The returned error, if not nil, can safely be cast to an ErrAsm value that
// will contain up to 10 entries.
func Assemble(name string, r io.Reader) (img []vm.Cell, err error) {
p := newParser()
img, err = p.Parse(name, r)
if err != nil {
return nil, err
}
return img, nil
}
// Disassemble disassembles the cells in the given slice at position pc to the
// specified io.Writer and returns the position of the next valid opcode.
func Disassemble(i []vm.Cell, pc int, w io.Writer) (next int) {
op := i[pc]
if op < 0 || op >= vm.Cell(len(opcodes)) {
io.WriteString(w, "call ")
io.WriteString(w, strconv.Itoa(int(op)))
} else if op != vm.OpLit {
io.WriteString(w, opcodes[op][0])
}
pc++
switch op {
case vm.OpLoop, vm.OpJump, vm.OpGtJump, vm.OpLtJump, vm.OpNeJump, vm.OpEqJump:
if pc < len(i) {
w.Write([]byte{' '})
}
fallthrough
case vm.OpLit:
if pc < len(i) {
io.WriteString(w, strconv.Itoa(int(i[pc])))
return pc + 1
}
io.WriteString(w, "???")
}
return pc
}