mirror of
https://github.com/taigrr/gopher-os
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30 lines
732 B
Go
30 lines
732 B
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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