43 lines
1.1 KiB
Go
43 lines
1.1 KiB
Go
|
package main
|
||
|
|
|
||
|
|
import "fmt"
|
||
|
|
|
||
|
|
// Memory provides an addressable map of integer cells
|
||
|
|
type Memory struct {
|
||
|
|
intern map[int]int
|
||
|
|
nextFree int
|
||
|
|
}
|
||
|
|
|
||
|
|
// Read takes a starting address and a count of cells to read after it;
|
||
|
|
// (0, 2) reads the first two cells out of memory, for example.
|
||
|
|
func (m *Memory) Read(addr int, count int) []int {
|
||
|
|
r := []int{}
|
||
|
|
for i := 0; i < count; i++ {
|
||
|
|
r = append(r, m.intern[addr+i])
|
||
|
|
}
|
||
|
|
return r
|
||
|
|
}
|
||
|
|
|
||
|
|
// Write inserts the given values into memory, overwriting any existing contents,
|
||
|
|
// starting at the provided memory address and incrementing upward.
|
||
|
|
func (m *Memory) Write(addr int, values []int) error {
|
||
|
|
if addr < 0 {
|
||
|
|
return fmt.Errorf("addr out of range")
|
||
|
|
}
|
||
|
|
for i := range values {
|
||
|
|
m.intern[addr+i] = values[i]
|
||
|
|
}
|
||
|
|
// we've written past our marker, note that
|
||
|
|
if m.nextFree < addr+len(values) {
|
||
|
|
m.nextFree = addr + len(values)
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// NextFreeAddress provides the furthest "out" address, beyond which is uninitialized memory.
|
||
|
|
// Old memory is never "reclaimed", even if the program manually 0s it out.
|
||
|
|
// If you want to build your own GC, knock yourself out.
|
||
|
|
func (m *Memory) NextFreeAddress() int {
|
||
|
|
return m.nextFree
|
||
|
|
}
|