mirror of
https://github.com/taigrr/gopher-os
synced 2025-01-18 04:43:13 -08:00
8dfc5d4e92
By setting up pwd as a Go workspace, we can trim import paths from something like "github.com/achilleasa/gopher-os/kernel" to just "kernel". These changes make forking easier and also allows us to move the code to a different git hosting provider without having to rewrite the imports.
50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
package mem
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import (
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"reflect"
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"unsafe"
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)
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// Memset sets size bytes at the given address to the supplied value. The implementation
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// is based on bytes.Repeat; instead of using a for loop, this function uses
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// log2(size) copy calls which should give us a speed boost as page addresses
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// are always aligned.
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func Memset(addr uintptr, value byte, size Size) {
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if size == 0 {
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return
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}
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// overlay a slice on top of this address region
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target := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
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Len: int(size),
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Cap: int(size),
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Data: addr,
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}))
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// Set first element and make log2(size) optimized copies
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target[0] = value
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for index := Size(1); index < size; index *= 2 {
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copy(target[index:], target[:index])
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}
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}
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// Memcopy copies size bytes from src to dst.
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func Memcopy(src, dst uintptr, size Size) {
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if size == 0 {
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return
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}
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srcSlice := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
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Len: int(size),
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Cap: int(size),
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Data: src,
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}))
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dstSlice := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
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Len: int(size),
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Cap: int(size),
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Data: dst,
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}))
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copy(dstSlice, srcSlice)
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}
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