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Merge pull request #505 from degasus/page_table

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A64/x64: Create a global_offset optimization for the page table.
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Merry 2019-12-31 18:52:10 +00:00 committed by MerryMage
commit 8c4bf322a1
2 changed files with 10 additions and 0 deletions
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7
include/dynarmic/A64/config.h
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@ -163,6 +163,13 @@ struct UserConfig {
/// relevant memory callback. /// relevant memory callback.
/// This is only used if page_table is not nullptr. /// This is only used if page_table is not nullptr.
bool silently_mirror_page_table = true; bool silently_mirror_page_table = true;
/// Determines if the pointer in the page_table shall be offseted locally or globally.
/// 'false' will access page_table[addr >> bits][addr & mask]
/// 'true' will access page_table[addr >> bits][addr]
/// Note: page_table[addr >> bits] will still be checked to verify active pages.
/// So there might be wrongly faulted pages which maps to nullptr.
/// This can be avoided by carefully allocating the memory region.
bool absolute_offset_page_table = false;
/// This option relates to translation. Generally when we run into an unpredictable /// This option relates to translation. Generally when we run into an unpredictable
/// instruction the ExceptionRaised callback is called. If this is true, we define /// instruction the ExceptionRaised callback is called. If this is true, we define

3
src/backend/x64/a64_emit_x64.cpp
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@ -737,6 +737,9 @@ static Xbyak::RegExp EmitVAddrLookup(BlockOfCode& code, A64EmitContext& ctx, Xby
code.mov(page_table, qword[page_table + tmp * sizeof(void*)]); code.mov(page_table, qword[page_table + tmp * sizeof(void*)]);
code.test(page_table, page_table); code.test(page_table, page_table);
code.jz(abort, code.T_NEAR); code.jz(abort, code.T_NEAR);
if (ctx.conf.absolute_offset_page_table) {
return page_table + vaddr;
}
code.mov(tmp, vaddr); code.mov(tmp, vaddr);
code.and_(tmp, static_cast<u32>(page_size - 1)); code.and_(tmp, static_cast<u32>(page_size - 1));
return page_table + tmp; return page_table + tmp;