Chore: improve tracing of code emits

2 files changed, 7 insertions, 3 deletions

diff --git a/vm/op_string.go b/vm/op_string.go
index ef3f3ee..ac5b557 100644
--- a/vm/op_string.go
+++ b/vm/op_string.go
@@ -42,11 +42,12 @@ func _() {
 	_ = x[Return-31]
 	_ = x[Sub-32]
 	_ = x[Subi-33]
+	_ = x[Swap-34]
 }
 
-const _Op_name = "NopAddAddrAssignFassignVassignCallCalliCallXDerefDupFdupEqualEqualSetExitFieldGreaterGrowIndexJumpJumpTrueJumpFalseJumpSetTrueJumpSetFalseLowerLoweriMulNewNotPopPushReturnSubSubi"
+const _Op_name = "NopAddAddrAssignFassignVassignCallCalliCallXDerefDupFdupEqualEqualSetExitFieldGreaterGrowIndexJumpJumpTrueJumpFalseJumpSetTrueJumpSetFalseLowerLoweriMulNewNotPopPushReturnSubSubiSwap"
 
-var _Op_index = [...]uint8{0, 3, 6, 10, 16, 23, 30, 34, 39, 44, 49, 52, 56, 61, 69, 73, 78, 85, 89, 94, 98, 106, 115, 126, 138, 143, 149, 152, 155, 158, 161, 165, 171, 174, 178}
+var _Op_index = [...]uint8{0, 3, 6, 10, 16, 23, 30, 34, 39, 44, 49, 52, 56, 61, 69, 73, 78, 85, 89, 94, 98, 106, 115, 126, 138, 143, 149, 152, 155, 158, 161, 165, 171, 174, 178, 182}
 
 func (i Op) String() string {
 	idx := int(i) - 0
diff --git a/vm/vm.go b/vm/vm.go
index 6c9f3e1..f981415 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -55,6 +55,7 @@ const (
 	Return                 // [r1 .. ri] -- ; exit frame: sp = fp, fp = pop
 	Sub                    // n1 n2 -- diff ; diff = n1 - n2
 	Subi                   // n1 -- diff ; diff = n1 - $1
+	Swap                   // --
 )
 
 // Instruction represents a virtual machine bytecode instruction.
@@ -65,7 +66,7 @@ type Instruction struct {
 }
 
 func (i Instruction) String() (s string) {
-	s = i.Op.String()
+	s = fmt.Sprintf("%4d: %v", i.Pos, i.Op)
 	var sb strings.Builder
 	for _, a := range i.Arg {
 		sb.WriteString(fmt.Sprintf(" %v", a))
@@ -226,6 +227,8 @@ func (m *Machine) Run() (err error) {
 			mem = mem[:sp-1]
 		case Subi:
 			mem[sp-1] = ValueOf(int(mem[sp-1].Data.Int()) - c.Arg[0])
+		case Swap:
+			mem[sp-2], mem[sp-1] = mem[sp-1], mem[sp-2]
 		case Index:
 			mem[sp-2].Data = mem[sp-1].Data.Index(int(mem[sp-2].Data.Int()))
 			mem = mem[:sp-1]