76 lines
1.3 KiB
Go
76 lines
1.3 KiB
Go
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package gmachine
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import (
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"fmt"
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"log"
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)
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// DefaultMemSize is the number of 64-bit words of memory which will be
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// allocated to a new G-machine by default.
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const DefaultMemSize = 1024
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const (
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OpHALT uint64 = iota
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OpNOOP
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OpINCA
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OpDECA
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OpSETA
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)
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type gMachine struct {
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// Memory 64-bit words of memory
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Memory []uint64
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// P (Program counter)
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P uint64
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// A (Register A)
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A uint64
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// Debugging flag, if turned on will print OpCodes
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DebugOn bool
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}
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func New() *gMachine {
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return &gMachine{
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P: 0,
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Memory: make([]uint64, DefaultMemSize),
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DebugOn: false,
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}
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}
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func (m *gMachine) NewProgram(program []uint64) {
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copy(m.Memory, program)
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m.Run()
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}
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func (m *gMachine) Run() {
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for {
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pointer := m.P
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m.P++
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switch m.Memory[pointer] {
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case OpHALT:
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m.printIfDebug("OpHALT")
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return
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case OpNOOP:
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m.printIfDebug("OpNOOP")
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case OpINCA:
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m.printIfDebug("OpINCA")
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m.A++
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case OpDECA:
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m.printIfDebug("OpDECA")
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m.A--
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case OpSETA:
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m.A = m.Memory[m.P]
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m.P++
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m.printIfDebug(fmt.Sprintf("OpSETA %d", m.A))
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default:
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m.printIfDebug(fmt.Sprintf("COULD NOT DETERMINE OP CODE, code:%d, pointer:%d", m.Memory[pointer], pointer))
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panic(pointer)
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}
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}
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}
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func (m *gMachine) printIfDebug(message string) {
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if m.DebugOn {
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log.Println(message)
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}
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}
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