58 lines
1.4 KiB
Plaintext
58 lines
1.4 KiB
Plaintext
Windows :: #import "Windows.kl"
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#import "Windows.kl"
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SizeU :: #strict U64
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OS_PAGE_SIZE :: 4096
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OS_Memory :: struct
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commit : SizeU
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reserve: SizeU
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data : *U8
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Arena :: struct
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memory: OS_Memory
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alignment: U64
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len: SizeU
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clamp_top_sizeu :: (val: SizeU, max: SizeU): SizeU
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if val > max
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return max
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return val
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get_align_offset :: (size: SizeU, align: SizeU): SizeU
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mask := align - 1
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val := size & mask
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if val != 0
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val = align - val
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return val
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align_up :: (size: SizeU, align: SizeU): SizeU
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result := size + get_align_offset(size, align)
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return result
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reserve :: (size: SizeU): OS_Memory
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result := OS_Memory{reserve=align_up(size, OS_PAGE_SIZE)}
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result.data = Windows.VirtualAlloc(
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flProtect = Windows.PAGE_READWRITE,
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dwSize = result.reserve,
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flAllocationType = Windows.MEM_RESERVE,
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lpAddress = 0)->*U8
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return result
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commit :: (m: *OS_Memory, size: SizeU): Bool
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commit_size := align_up(size, OS_PAGE_SIZE)
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total_commit := m.commit + commit_size
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clamped_commit := clamp_top_sizeu(total_commit, m.reserve)
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adjusted_commit := clamped_commit - m.commit
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if adjusted_commit != 0
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result := Windows.VirtualAlloc(
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lpAddress = (m.data + m.commit)->*void,
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dwSize = adjusted_commit,
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flAllocationType = Windows.MEM_COMMIT,
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flProtect = Windows.PAGE_READWRITE,
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)
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m.commit += adjusted_commit
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return true
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return false
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