Merge pull request #3369 from ReinUsesLisp/shf

shader/shift: Implement SHF

2 files changed, 122 insertions, 11 deletions

diff --git a/src/video_core/engines/shader_bytecode.h b/src/video_core/engines/shader_bytecode.h
index 81b6d9eff..402869fde 100644
--- a/src/video_core/engines/shader_bytecode.h
+++ b/src/video_core/engines/shader_bytecode.h
@@ -624,6 +624,19 @@ enum class ShuffleOperation : u64 {
     Bfly = 3, // shuffleXorNV
 };
 
+enum class ShfType : u64 {
+    Bits32 = 0,
+    U64 = 2,
+    S64 = 3,
+};
+
+enum class ShfXmode : u64 {
+    None = 0,
+    HI = 1,
+    X = 2,
+    XHI = 3,
+};
+
 union Instruction {
     constexpr Instruction& operator=(const Instruction& instr) {
         value = instr.value;
@@ -776,6 +789,13 @@ union Instruction {
     } shr;
 
     union {
+        BitField<37, 2, ShfType> type;
+        BitField<48, 2, ShfXmode> xmode;
+        BitField<50, 1, u64> wrap;
+        BitField<20, 6, u64> immediate;
+    } shf;
+
+    union {
         BitField<39, 5, u64> shift_amount;
         BitField<48, 1, u64> negate_b;
         BitField<49, 1, u64> negate_a;
diff --git a/src/video_core/shader/decode/shift.cpp b/src/video_core/shader/decode/shift.cpp
index d419e9c45..3b391d3e6 100644
--- a/src/video_core/shader/decode/shift.cpp
+++ b/src/video_core/shader/decode/shift.cpp
@@ -10,8 +10,80 @@
 
 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 is_full = Operation(OperationCode::LogicalIEqual, shift, Immediate(32));
+    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]};
@@ -28,29 +100,48 @@ u32 ShaderIR::DecodeShift(NodeBlock& bb, u32 pc) {
         }
     }();
 
-    switch (opcode->get().GetId()) {
+    switch (const auto opid = opcode->get().GetId(); opid) {
     case OpCode::Id::SHR_C:
     case OpCode::Id::SHR_R:
     case OpCode::Id::SHR_IMM: {
-        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));
-        }
+        op_b = instr.shr.wrap ? WrapShift(move(op_b)) : ClampShift(move(op_b));
 
         Node value = SignedOperation(OperationCode::IArithmeticShiftRight, instr.shift.is_signed,
-                                     std::move(op_a), std::move(op_b));
+                                     move(op_a), move(op_b));
         SetInternalFlagsFromInteger(bb, value, instr.generates_cc);
-        SetRegister(bb, instr.gpr0, std::move(value));
+        SetRegister(bb, instr.gpr0, move(value));
         break;
     }
     case OpCode::Id::SHL_C:
     case OpCode::Id::SHL_R:
     case OpCode::Id::SHL_IMM: {
-        const Node value = Operation(OperationCode::ILogicalShiftLeft, op_a, op_b);
+        Node value = Operation(OperationCode::ILogicalShiftLeft, op_a, op_b);
         SetInternalFlagsFromInteger(bb, value, instr.generates_cc);
-        SetRegister(bb, instr.gpr0, value);
+        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: