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37 lines
1.8 KiB
37 lines
1.8 KiB
#include <vm_lifters.hpp>
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namespace vm
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{
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// our undefined behavior is that we don't model cases where the shift count is zero...
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llvm::Value *lifters_t::shr_flags( vm::devirt_t *rtn, std::uint8_t byte_size, llvm::Value *lhs, llvm::Value *rhs,
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llvm::Value *result )
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{
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auto op_size = llvm::IntegerType::get( *rtn->llvm_ctx, byte_size * 8 );
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auto msb = rtn->ir_builder->CreateLShr( lhs, ( byte_size * 8 ) - 1 );
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auto cf = rtn->ir_builder->CreateZExt( msb, llvm::IntegerType::get( *rtn->llvm_ctx, 64 ) );
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auto of =
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rtn->compute_sf( byte_size, lhs ); // we reuse the compute_sf helper since the flag expression is the same
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auto sf = rtn->compute_sf( byte_size, result );
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auto zf = rtn->compute_zf( byte_size, result );
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auto pf = llvm::ConstantInt::get( llvm::IntegerType::get( *rtn->llvm_ctx, 64 ), 0 );
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return rtn->combine_flags( cf, pf, llvm::ConstantInt::get( llvm::IntegerType::get( *rtn->llvm_ctx, 64 ), 0 ),
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zf, sf, of );
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}
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lifters_t::lifter_callback_t lifters_t::shrq =
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[ & ]( vm::devirt_t *rtn, const vm::instrs::code_block_t &vm_code_block,
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const vm::instrs::virt_instr_t &vinstr, llvm::IRBuilder<> *ir_builder ) {
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auto t1 = rtn->pop( 8 );
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auto t2 = rtn->pop( 2 );
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auto t3 = ir_builder->CreateIntCast( t2, llvm::IntegerType::get( *rtn->llvm_ctx, 64 ), false );
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auto t4 = ir_builder->CreateLShr( t1, t3 );
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auto &vmp_rtn = rtn->vmp_rtns.back();
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auto flags = lifters_t::shr_flags( rtn, 8, t1, t3, t4 );
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ir_builder->CreateStore( flags, vmp_rtn->flags );
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rtn->push( 8, t4 );
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rtn->push( 8, rtn->load_value( 8, vmp_rtn->flags ) );
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};
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} // namespace vm
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