diff options
Diffstat (limited to 'vm/vm.go')
| -rw-r--r-- | vm/vm.go | 11 |
1 files changed, 11 insertions, 0 deletions
@@ -1,3 +1,4 @@ +// Package vm implement a stack based virtual machine. package vm import ( @@ -85,6 +86,7 @@ var strop = [...]string{ // for VM tracing. Vassign: "Vassign", } +// Code represents the virtual machine byte code. type Code [][]int64 // Machine represents a virtual machine. @@ -256,19 +258,24 @@ func (m *Machine) Run() (err error) { } } +// PushCode adds instructions to the machine code. func (m *Machine) PushCode(code ...[]int64) (p int) { p = len(m.code) m.code = append(m.code, code...) return p } +// SetIP sets the value of machine instruction pointer to given index. func (m *Machine) SetIP(ip int) { m.ip = ip } + +// Push pushes data values on top of machine memory stack. func (m *Machine) Push(v ...Value) (l int) { l = len(m.mem) m.mem = append(m.mem, v...) return l } +// Pop removes and returns the value on the top of machine stack. func (m *Machine) Pop() (v Value) { l := len(m.mem) - 1 v = m.mem[l] @@ -276,6 +283,7 @@ func (m *Machine) Pop() (v Value) { return v } +// Top returns (but not remove) the value on the top of machine stack. func (m *Machine) Top() (v Value) { if l := len(m.mem); l > 0 { v = m.mem[l-1] @@ -283,12 +291,14 @@ func (m *Machine) Top() (v Value) { return v } +// PopExit removes the last machine code instruction if is Exit. func (m *Machine) PopExit() { if l := len(m.code); l > 0 && m.code[l-1][1] == Exit { m.code = m.code[:l-1] } } +// CodeString returns the string representation of a machine code instruction. func CodeString(op []int64) string { switch len(op) { case 2: @@ -317,6 +327,7 @@ func slint(a []int64) []int { return r } +// Vstring returns the string repreentation of a list of values. func Vstring(lv []Value) string { s := "[" for _, v := range lv { |