suyu/src/video_core/shader/decode/shift.cpp
Lioncash cd2a12e78f decode/shift: Remove unused variable within Shift()
Removes a redundant variable that is already satisfied by the IsFull()
utility function.
2020-04-16 00:16:06 -04:00

153 lines
6.1 KiB
C++

// Copyright 2018 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/assert.h"
#include "common/common_types.h"
#include "video_core/engines/shader_bytecode.h"
#include "video_core/shader/node_helper.h"
#include "video_core/shader/shader_ir.h"
namespace VideoCommon::Shader {
using std::move;
using Tegra::Shader::Instruction;
using Tegra::Shader::OpCode;
using Tegra::Shader::ShfType;
using Tegra::Shader::ShfXmode;
namespace {
Node IsFull(Node shift) {
return Operation(OperationCode::LogicalIEqual, move(shift), Immediate(32));
}
Node Shift(OperationCode opcode, Node value, Node shift) {
Node shifted = Operation(opcode, move(value), shift);
return Operation(OperationCode::Select, IsFull(move(shift)), Immediate(0), move(shifted));
}
Node ClampShift(Node shift, s32 size = 32) {
shift = Operation(OperationCode::IMax, move(shift), Immediate(0));
return Operation(OperationCode::IMin, move(shift), Immediate(size));
}
Node WrapShift(Node shift, s32 size = 32) {
return Operation(OperationCode::UBitwiseAnd, move(shift), Immediate(size - 1));
}
Node ShiftRight(Node low, Node high, Node shift, Node low_shift, ShfType type) {
// These values are used when the shift value is less than 32
Node less_low = Shift(OperationCode::ILogicalShiftRight, low, shift);
Node less_high = Shift(OperationCode::ILogicalShiftLeft, high, low_shift);
Node less = Operation(OperationCode::IBitwiseOr, move(less_high), move(less_low));
if (type == ShfType::Bits32) {
// On 32 bit shifts we are either full (shifting 32) or shifting less than 32 bits
return Operation(OperationCode::Select, IsFull(move(shift)), move(high), move(less));
}
// And these when it's larger than or 32
const bool is_signed = type == ShfType::S64;
const auto opcode = SignedToUnsignedCode(OperationCode::IArithmeticShiftRight, is_signed);
Node reduced = Operation(OperationCode::IAdd, shift, Immediate(-32));
Node greater = Shift(opcode, high, move(reduced));
Node is_less = Operation(OperationCode::LogicalILessThan, shift, Immediate(32));
Node is_zero = Operation(OperationCode::LogicalIEqual, move(shift), Immediate(0));
Node value = Operation(OperationCode::Select, move(is_less), move(less), move(greater));
return Operation(OperationCode::Select, move(is_zero), move(high), move(value));
}
Node ShiftLeft(Node low, Node high, Node shift, Node low_shift, ShfType type) {
// These values are used when the shift value is less than 32
Node less_low = Operation(OperationCode::ILogicalShiftRight, low, low_shift);
Node less_high = Operation(OperationCode::ILogicalShiftLeft, high, shift);
Node less = Operation(OperationCode::IBitwiseOr, move(less_low), move(less_high));
if (type == ShfType::Bits32) {
// On 32 bit shifts we are either full (shifting 32) or shifting less than 32 bits
return Operation(OperationCode::Select, IsFull(move(shift)), move(low), move(less));
}
// And these when it's larger than or 32
Node reduced = Operation(OperationCode::IAdd, shift, Immediate(-32));
Node greater = Shift(OperationCode::ILogicalShiftLeft, move(low), move(reduced));
Node is_less = Operation(OperationCode::LogicalILessThan, shift, Immediate(32));
Node is_zero = Operation(OperationCode::LogicalIEqual, move(shift), Immediate(0));
Node value = Operation(OperationCode::Select, move(is_less), move(less), move(greater));
return Operation(OperationCode::Select, move(is_zero), move(high), move(value));
}
} // Anonymous namespace
u32 ShaderIR::DecodeShift(NodeBlock& bb, u32 pc) {
const Instruction instr = {program_code[pc]};
const auto opcode = OpCode::Decode(instr);
Node op_a = GetRegister(instr.gpr8);
Node op_b = [this, instr] {
if (instr.is_b_imm) {
return Immediate(instr.alu.GetSignedImm20_20());
} else if (instr.is_b_gpr) {
return GetRegister(instr.gpr20);
} else {
return GetConstBuffer(instr.cbuf34.index, instr.cbuf34.GetOffset());
}
}();
switch (const auto opid = opcode->get().GetId(); opid) {
case OpCode::Id::SHR_C:
case OpCode::Id::SHR_R:
case OpCode::Id::SHR_IMM: {
op_b = instr.shr.wrap ? WrapShift(move(op_b)) : ClampShift(move(op_b));
Node value = SignedOperation(OperationCode::IArithmeticShiftRight, instr.shift.is_signed,
move(op_a), move(op_b));
SetInternalFlagsFromInteger(bb, value, instr.generates_cc);
SetRegister(bb, instr.gpr0, move(value));
break;
}
case OpCode::Id::SHL_C:
case OpCode::Id::SHL_R:
case OpCode::Id::SHL_IMM: {
Node value = Operation(OperationCode::ILogicalShiftLeft, op_a, op_b);
SetInternalFlagsFromInteger(bb, value, instr.generates_cc);
SetRegister(bb, instr.gpr0, move(value));
break;
}
case OpCode::Id::SHF_RIGHT_R:
case OpCode::Id::SHF_RIGHT_IMM:
case OpCode::Id::SHF_LEFT_R:
case OpCode::Id::SHF_LEFT_IMM: {
UNIMPLEMENTED_IF(instr.generates_cc);
UNIMPLEMENTED_IF_MSG(instr.shf.xmode != ShfXmode::None, "xmode={}",
static_cast<int>(instr.shf.xmode.Value()));
if (instr.is_b_imm) {
op_b = Immediate(static_cast<u32>(instr.shf.immediate));
}
const s32 size = instr.shf.type == ShfType::Bits32 ? 32 : 64;
Node shift = instr.shf.wrap ? WrapShift(move(op_b), size) : ClampShift(move(op_b), size);
Node negated_shift = Operation(OperationCode::INegate, shift);
Node low_shift = Operation(OperationCode::IAdd, move(negated_shift), Immediate(32));
const bool is_right = opid == OpCode::Id::SHF_RIGHT_R || opid == OpCode::Id::SHF_RIGHT_IMM;
Node value = (is_right ? ShiftRight : ShiftLeft)(
move(op_a), GetRegister(instr.gpr39), move(shift), move(low_shift), instr.shf.type);
SetRegister(bb, instr.gpr0, move(value));
break;
}
default:
UNIMPLEMENTED_MSG("Unhandled shift instruction: {}", opcode->get().GetName());
}
return pc;
}
} // namespace VideoCommon::Shader