Implement soft float64 conversion on shaders when host has no support (#5159)

* Implement soft float64 conversion on shaders when host has no support

* Shader cache version bump

* Fix rebase error

4 files changed, 171 insertions, 3 deletions

diff --git a/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs b/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs
index 7dd267f3..6958b86f 100644
--- a/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs
+++ b/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs
@@ -45,12 +45,101 @@ namespace Ryujinx.Graphics.Shader.Translation
         {
             return functionName switch
             {
+                HelperFunctionName.ConvertDoubleToFloat => GenerateConvertDoubleToFloatFunction(),
+                HelperFunctionName.ConvertFloatToDouble => GenerateConvertFloatToDoubleFunction(),
                 HelperFunctionName.TexelFetchScale => GenerateTexelFetchScaleFunction(),
                 HelperFunctionName.TextureSizeUnscale => GenerateTextureSizeUnscaleFunction(),
                 _ => throw new ArgumentException($"Invalid function name {functionName}")
             };
         }
 
+        private Function GenerateConvertDoubleToFloatFunction()
+        {
+            EmitterContext context = new EmitterContext();
+
+            Operand valueLow = Argument(0);
+            Operand valueHigh = Argument(1);
+
+            Operand mantissaLow = context.BitwiseAnd(valueLow, Const(((1 << 22) - 1)));
+            Operand mantissa = context.ShiftRightU32(valueLow, Const(22));
+
+            mantissa = context.BitwiseOr(mantissa, context.ShiftLeft(context.BitwiseAnd(valueHigh, Const(0xfffff)), Const(10)));
+            mantissa = context.BitwiseOr(mantissa, context.ConditionalSelect(mantissaLow, Const(1), Const(0)));
+
+            Operand exp = context.BitwiseAnd(context.ShiftRightU32(valueHigh, Const(20)), Const(0x7ff));
+            Operand sign = context.ShiftRightS32(valueHigh, Const(31));
+
+            Operand resultSign = context.ShiftLeft(sign, Const(31));
+
+            Operand notZero = context.BitwiseOr(mantissa, exp);
+
+            Operand lblNotZero = Label();
+
+            context.BranchIfTrue(lblNotZero, notZero);
+
+            context.Return(resultSign);
+
+            context.MarkLabel(lblNotZero);
+
+            Operand notNaNOrInf = context.ICompareNotEqual(exp, Const(0x7ff));
+
+            mantissa = context.BitwiseOr(mantissa, Const(0x40000000));
+            exp = context.ISubtract(exp, Const(0x381));
+
+            // Note: Overflow cases are not handled here and might produce incorrect results.
+
+            Operand roundBits = context.BitwiseAnd(mantissa, Const(0x7f));
+            Operand roundBitsXor64 = context.BitwiseExclusiveOr(roundBits, Const(0x40));
+            mantissa = context.ShiftRightU32(context.IAdd(mantissa, Const(0x40)), Const(7));
+            mantissa = context.BitwiseAnd(mantissa, context.ConditionalSelect(roundBitsXor64, Const(~0), Const(~1)));
+
+            exp = context.ConditionalSelect(mantissa, exp, Const(0));
+            exp = context.ConditionalSelect(notNaNOrInf, exp, Const(0xff));
+
+            Operand result = context.IAdd(context.IAdd(mantissa, context.ShiftLeft(exp, Const(23))), resultSign);
+
+            context.Return(result);
+
+            return new Function(ControlFlowGraph.Create(context.GetOperations()).Blocks, "ConvertDoubleToFloat", true, 2, 0);
+        }
+
+        private Function GenerateConvertFloatToDoubleFunction()
+        {
+            EmitterContext context = new EmitterContext();
+
+            Operand value = Argument(0);
+
+            Operand mantissa = context.BitwiseAnd(value, Const(0x7fffff));
+            Operand exp = context.BitwiseAnd(context.ShiftRightU32(value, Const(23)), Const(0xff));
+            Operand sign = context.ShiftRightS32(value, Const(31));
+
+            Operand notNaNOrInf = context.ICompareNotEqual(exp, Const(0xff));
+            Operand expNotZero = context.ICompareNotEqual(exp, Const(0));
+            Operand notDenorm = context.BitwiseOr(expNotZero, context.ICompareEqual(mantissa, Const(0)));
+
+            exp = context.IAdd(exp, Const(0x380));
+
+            Operand shiftDist = context.ISubtract(Const(32), context.FindMSBU32(mantissa));
+            Operand normExp = context.ISubtract(context.ISubtract(Const(1), shiftDist), Const(1));
+            Operand normMant = context.ShiftLeft(mantissa, shiftDist);
+
+            exp = context.ConditionalSelect(notNaNOrInf, exp, Const(0x7ff));
+            exp = context.ConditionalSelect(notDenorm, exp, normExp);
+            mantissa = context.ConditionalSelect(expNotZero, mantissa, normMant);
+
+            Operand resultLow = context.ShiftLeft(mantissa, Const(29));
+            Operand resultHigh = context.ShiftRightU32(mantissa, Const(3));
+
+            resultHigh = context.IAdd(resultHigh, context.ShiftLeft(exp, Const(20)));
+            resultHigh = context.IAdd(resultHigh, context.ShiftLeft(sign, Const(31)));
+
+            context.Copy(Argument(1), resultLow);
+            context.Copy(Argument(2), resultHigh);
+            context.Return();
+
+            return new Function(ControlFlowGraph.Create(context.GetOperations()).Blocks, "ConvertFloatToDouble", false, 1, 2);
+        }
+
         private Function GenerateTexelFetchScaleFunction()
         {
             EmitterContext context = new EmitterContext();
diff --git a/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionName.cs b/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionName.cs
index 5accdf65..8c37c34c 100644
--- a/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionName.cs
+++ b/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionName.cs
@@ -1,10 +1,9 @@
-using Ryujinx.Graphics.Shader.IntermediateRepresentation;
-using System.Collections.Generic;
-
 namespace Ryujinx.Graphics.Shader.Translation
 {
     enum HelperFunctionName
     {
+        ConvertDoubleToFloat,
+        ConvertFloatToDouble,
         TexelFetchScale,
         TextureSizeUnscale
     }
diff --git a/src/Ryujinx.Graphics.Shader/Translation/Optimizations/DoubleToFloat.cs b/src/Ryujinx.Graphics.Shader/Translation/Optimizations/DoubleToFloat.cs
new file mode 100644
index 00000000..42bce5cc
--- /dev/null
+++ b/src/Ryujinx.Graphics.Shader/Translation/Optimizations/DoubleToFloat.cs
@@ -0,0 +1,70 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System.Collections.Generic;
+
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class DoubleToFloat
+    {
+        public static void RunPass(HelperFunctionManager hfm, BasicBlock block)
+        {
+            for (LinkedListNode<INode> node = block.Operations.First; node != null; node = node.Next)
+            {
+                if (node.Value is not Operation operation)
+                {
+                    continue;
+                }
+
+                node = InsertSoftFloat64(hfm, node);
+            }
+        }
+
+        private static LinkedListNode<INode> InsertSoftFloat64(HelperFunctionManager hfm, LinkedListNode<INode> node)
+        {
+            Operation operation = (Operation)node.Value;
+
+            if (operation.Inst == Instruction.PackDouble2x32)
+            {
+                int functionId = hfm.GetOrCreateFunctionId(HelperFunctionName.ConvertDoubleToFloat);
+
+                Operand[] callArgs = new Operand[] { Const(functionId), operation.GetSource(0), operation.GetSource(1) };
+
+                Operand floatValue = operation.Dest;
+
+                operation.Dest = null;
+
+                LinkedListNode<INode> newNode = node.List.AddBefore(node, new Operation(Instruction.Call, 0, floatValue, callArgs));
+
+                Utils.DeleteNode(node, operation);
+
+                return newNode;
+            }
+            else if (operation.Inst == Instruction.UnpackDouble2x32)
+            {
+                int functionId = hfm.GetOrCreateFunctionId(HelperFunctionName.ConvertFloatToDouble);
+
+                // TODO: Allow UnpackDouble2x32 to produce two outputs and get rid of "operation.Index".
+
+                Operand resultLow = operation.Index == 0 ? operation.Dest : Local();
+                Operand resultHigh = operation.Index == 1 ? operation.Dest : Local();
+
+                operation.Dest = null;
+
+                Operand[] callArgs = new Operand[] { Const(functionId), operation.GetSource(0), resultLow, resultHigh };
+
+                LinkedListNode<INode> newNode = node.List.AddBefore(node, new Operation(Instruction.Call, 0, (Operand)null, callArgs));
+
+                Utils.DeleteNode(node, operation);
+
+                return newNode;
+            }
+            else
+            {
+                operation.TurnDoubleIntoFloat();
+
+                return node;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs b/src/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs
index bdb3a62e..8d2669c0 100644
--- a/src/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs
+++ b/src/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs
@@ -11,8 +11,12 @@ namespace Ryujinx.Graphics.Shader.Translation.Optimizations
         {
             RunOptimizationPasses(blocks, config);
 
+            // TODO: Some of those are not optimizations and shouldn't be here.
+
             GlobalToStorage.RunPass(hfm, blocks, config);
 
+            bool hostSupportsShaderFloat64 = config.GpuAccessor.QueryHostSupportsShaderFloat64();
+
             // Those passes are looking for specific patterns and only needs to run once.
             for (int blkIndex = 0; blkIndex < blocks.Length; blkIndex++)
             {
@@ -24,6 +28,12 @@ namespace Ryujinx.Graphics.Shader.Translation.Optimizations
                 {
                     EliminateMultiplyByFragmentCoordW(blocks[blkIndex]);
                 }
+
+                // If the host does not support double operations, we need to turn them into float operations.
+                if (!hostSupportsShaderFloat64)
+                {
+                    DoubleToFloat.RunPass(hfm, blocks[blkIndex]);
+                }
             }
 
             // Run optimizations one last time to remove any code that is now optimizable after above passes.