From ac4a2bac00e4d794349e6af922fa0f7bcf4c47f2 Mon Sep 17 00:00:00 2001
From: lash <dev@holbrook.no>
Date: Sun, 2 Apr 2023 15:00:56 +0100
Subject: [PATCH] Add disasembler-ish - bytecode to instruction debug output

---
 README.md             |   9 ++++
 go/dev/disasm/main.go |  27 ++++++++++
 go/vm/debug.go        |  93 ++++++++++++++++++++++++++++++++++
 go/vm/debug_test.go   | 114 ++++++++++++++++++++++++++++++++++++++++++
 go/vm/opcodes.go      |  14 ++++++
 go/vm/runner.go       |   4 --
 go/vm/vm.go           |   2 +-
 7 files changed, 258 insertions(+), 5 deletions(-)
 create mode 100644 go/dev/disasm/main.go
 create mode 100644 go/vm/debug.go
 create mode 100644 go/vm/debug_test.go

diff --git a/README.md b/README.md
index 0ee3724..ddf8c2b 100644
--- a/README.md
+++ b/README.md
@@ -163,6 +163,15 @@ If `data_directory` is not set, current directory will be used.
 if `root_symbol` is not set, the symbol `root` will be used.
 
 
+### Disassembler
+
+`go run ./dev/testdata/ <binary_file>`
+
+The output from this tool is to be considered debugging output, as the assembly language isn't formalized yet.
+
+In the meantime, it will at least list all the instructions, and thus validate the file.
+
+
 ### Assembler
 
 **TBD**
diff --git a/go/dev/disasm/main.go b/go/dev/disasm/main.go
new file mode 100644
index 0000000..c5f8954
--- /dev/null
+++ b/go/dev/disasm/main.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"io/ioutil"
+
+	"git.defalsify.org/festive/vm"
+)
+
+func main() {
+	if (len(os.Args) < 2) {
+		os.Exit(1)
+	}
+	fp := os.Args[1]
+	v, err := ioutil.ReadFile(fp)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "read error: %v", err)
+		os.Exit(1)
+	}
+	r, err := vm.ToString(v)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "parse error: %v", err)
+		os.Exit(1)
+	}
+	fmt.Printf(r)
+}
diff --git a/go/vm/debug.go b/go/vm/debug.go
new file mode 100644
index 0000000..d74533e
--- /dev/null
+++ b/go/vm/debug.go
@@ -0,0 +1,93 @@
+package vm
+
+import (
+	"fmt"
+)
+
+
+func ToString(b []byte) (string, error) {
+	var s string
+	running := true
+	for running {
+		op, bb, err := opSplit(b)
+		b = bb
+		if err != nil {
+			return "", err
+		}
+		opString := OpcodeString[op]
+		if opString == "" {
+			return "", fmt.Errorf("unknown opcode: %v", op)
+		}
+		s += opString
+
+		switch op {
+		case CATCH:
+			r, n, m, bb, err := ParseCatch(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			vv := 0
+			if m {
+				vv = 1
+			}
+			s = fmt.Sprintf("%s %s %v %v # invertmatch=%v", s, r, n, vv, m)
+		case CROAK:
+			n, m, bb, err := ParseCroak(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			vv := 0
+			if m {
+				vv = 1
+			}
+			s = fmt.Sprintf("%s %v %v # invertmatch=%v", s, n, vv, m)
+		case LOAD:
+			r, n, bb, err := ParseLoad(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %s %v", s, r, n)
+		case RELOAD:
+			r, bb, err := ParseReload(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %s", s, r)
+		case MAP:
+			r, bb, err := ParseMap(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %s", s, r)
+		case MOVE:
+			r, bb, err := ParseMove(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %s", s, r)
+		case INCMP:
+			r, v, bb, err := ParseInCmp(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %s %s", s, r, v)
+		case HALT:
+			b, err = ParseHalt(b)
+			if err != nil {
+				return "", err
+			}
+		}
+		s += "\n"
+		if len(b) == 0 {
+			running = false
+		}
+	}
+	return s, nil
+}
diff --git a/go/vm/debug_test.go b/go/vm/debug_test.go
new file mode 100644
index 0000000..1e1ba65
--- /dev/null
+++ b/go/vm/debug_test.go
@@ -0,0 +1,114 @@
+package vm
+
+import (
+	"testing"
+)
+
+
+func TestToString(t *testing.T) {
+	var b []byte
+	var r string
+	var expect string
+	var err error
+
+	b = NewLine(nil, CATCH, []string{"xyzzy"}, []byte{0x0d}, []uint8{1})
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "CATCH xyzzy 13 1 # invertmatch=true\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, CROAK, nil, []byte{0x0d}, []uint8{1})
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "CROAK 13 1 # invertmatch=true\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, LOAD, []string{"foo"}, []byte{0x0a}, nil)
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "LOAD foo 10\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, RELOAD, []string{"bar"}, nil, nil)
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "RELOAD bar\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, MAP, []string{"inky_pinky"}, nil, nil) 
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "MAP inky_pinky\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, MOVE, []string{"blinky_clyde"}, nil, nil) 
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "MOVE blinky_clyde\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, HALT, nil, nil, nil) 
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "HALT\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+
+	b = NewLine(nil, INCMP, []string{"13", "baz"}, nil, nil) 
+	r, err = ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect = "INCMP 13 baz\n"
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+}
+
+func TestToStringMultiple(t *testing.T) {
+	b := NewLine(nil, INCMP, []string{"1", "foo"}, nil, nil)
+	b = NewLine(b, INCMP, []string{"2", "bar"}, nil, nil)
+	b = NewLine(b, CATCH, []string{"aiee"}, []byte{0x02, 0x9a}, []uint8{0})
+	b = NewLine(b, LOAD, []string{"inky"}, []byte{0x2a}, nil)
+	b = NewLine(b, HALT, nil, nil, nil)
+	r, err := ToString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect := `INCMP 1 foo
+INCMP 2 bar
+CATCH aiee 666 0 # invertmatch=false
+LOAD inky 42
+HALT
+`
+	if r != expect {
+		t.Fatalf("expected:\n\t%v\ngot:\n\t%v", expect, r)
+	}
+}
diff --git a/go/vm/opcodes.go b/go/vm/opcodes.go
index d375e88..b7ec627 100644
--- a/go/vm/opcodes.go
+++ b/go/vm/opcodes.go
@@ -17,3 +17,17 @@ const (
 	INCMP = 8
 	_MAX = 8
 )
+
+var (
+	OpcodeString = map[Opcode]string{
+		NOOP: "NOOP",
+		CATCH: "CATCH",
+		CROAK: "CROAK",
+		LOAD: "LOAD",
+		RELOAD: "RELOAD",
+		MAP: "MAP",
+		MOVE: "MOVE",
+		HALT: "HALT",
+		INCMP: "INCMP",
+	}
+)
diff --git a/go/vm/runner.go b/go/vm/runner.go
index 9e3185f..ca03cf0 100644
--- a/go/vm/runner.go
+++ b/go/vm/runner.go
@@ -19,13 +19,11 @@ import (
 func Run(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
 	running := true
 	for running {
-		log.Printf("code before 0x%x", b)
 		op, bb, err := opSplit(b)
 		if err != nil {
 			return b, err
 		}
 		b = bb
-		log.Printf("code after 0x%x", b)
 		switch op {
 		case CATCH:
 			b, err = RunCatch(b, st, rs, ctx)
@@ -41,7 +39,6 @@ func Run(b []byte, st *state.State, rs resource.Resource, ctx context.Context) (
 			b, err = RunMove(b, st, rs, ctx)
 		case INCMP:
 			b, err = RunInCmp(b, st, rs, ctx)
-			log.Printf("bb %v", b)
 		case HALT:
 			b, err = RunHalt(b, st, rs, ctx)
 			return b, err
@@ -51,7 +48,6 @@ func Run(b []byte, st *state.State, rs resource.Resource, ctx context.Context) (
 		if err != nil {
 			return b, err
 		}
-		log.Printf("aa %v", b)
 		if len(b) == 0 {
 			return []byte{}, nil
 		}
diff --git a/go/vm/vm.go b/go/vm/vm.go
index db00c6b..60db316 100644
--- a/go/vm/vm.go
+++ b/go/vm/vm.go
@@ -7,7 +7,7 @@ import (
 	"git.defalsify.org/festive/state"
 )
 
-func Parse(b []byte) (Opcode, []byte, error) {
+func ParseOp(b []byte) (Opcode, []byte, error) {
 	op, b, err := opSplit(b)
 	if err != nil {
 		return NOOP, b, err