From 77ef4fa9078b56c3fcaded3a618cf95fe21e66d4 Mon Sep 17 00:00:00 2001 From: ReinUsesLisp Date: Sat, 31 Aug 2019 17:06:00 -0300 Subject: shader/shift: Implement SHR wrapped and clamped variants Nvidia defaults to wrapped shifts, but this is undefined behaviour on OpenGL's spec. Explicitly mask/clamp according to what the guest shader requires. --- src/video_core/shader/decode/shift.cpp | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) (limited to 'src/video_core/shader/decode') diff --git a/src/video_core/shader/decode/shift.cpp b/src/video_core/shader/decode/shift.cpp index 2ac16eeb0..f6ee68a54 100644 --- a/src/video_core/shader/decode/shift.cpp +++ b/src/video_core/shader/decode/shift.cpp @@ -17,8 +17,8 @@ u32 ShaderIR::DecodeShift(NodeBlock& bb, u32 pc) { const Instruction instr = {program_code[pc]}; const auto opcode = OpCode::Decode(instr); - const Node op_a = GetRegister(instr.gpr8); - const Node op_b = [&]() { + Node op_a = GetRegister(instr.gpr8); + Node op_b = [&]() { if (instr.is_b_imm) { return Immediate(instr.alu.GetSignedImm20_20()); } else if (instr.is_b_gpr) { @@ -32,16 +32,23 @@ u32 ShaderIR::DecodeShift(NodeBlock& bb, u32 pc) { case OpCode::Id::SHR_C: case OpCode::Id::SHR_R: case OpCode::Id::SHR_IMM: { - const Node value = SignedOperation(OperationCode::IArithmeticShiftRight, - instr.shift.is_signed, PRECISE, op_a, op_b); + if (instr.shr.wrap) { + op_b = Operation(OperationCode::UBitwiseAnd, std::move(op_b), Immediate(0x1f)); + } else { + op_b = Operation(OperationCode::IMax, std::move(op_b), Immediate(0)); + op_b = Operation(OperationCode::IMin, std::move(op_b), Immediate(31)); + } + + Node value = SignedOperation(OperationCode::IArithmeticShiftRight, instr.shift.is_signed, + std::move(op_a), std::move(op_b)); SetInternalFlagsFromInteger(bb, value, instr.generates_cc); - SetRegister(bb, instr.gpr0, value); + SetRegister(bb, instr.gpr0, std::move(value)); break; } case OpCode::Id::SHL_C: case OpCode::Id::SHL_R: case OpCode::Id::SHL_IMM: { - const Node value = Operation(OperationCode::ILogicalShiftLeft, PRECISE, op_a, op_b); + const Node value = Operation(OperationCode::ILogicalShiftLeft, op_a, op_b); SetInternalFlagsFromInteger(bb, value, instr.generates_cc); SetRegister(bb, instr.gpr0, value); break; -- cgit v1.2.3