Implement VMNMX shader instruction (#1032)

* Implement VMNMX shader instruction

* No need for the gap on the enum

* Fix typo

5 files changed, 232 insertions, 4 deletions

diff --git a/Ryujinx.Graphics.Shader/Decoders/OpCodeTable.cs b/Ryujinx.Graphics.Shader/Decoders/OpCodeTable.cs
index 3878dd87..4579d650 100644
--- a/Ryujinx.Graphics.Shader/Decoders/OpCodeTable.cs
+++ b/Ryujinx.Graphics.Shader/Decoders/OpCodeTable.cs
@@ -205,6 +205,7 @@ namespace Ryujinx.Graphics.Shader.Decoders
             Set("1101111101001x", InstEmit.Txq,     typeof(OpCodeTex));
             Set("1101111101010x", InstEmit.TxqB,    typeof(OpCodeTex));
             Set("01011111xxxxxx", InstEmit.Vmad,    typeof(OpCodeVideo));
+            Set("0011101xxxxxxx", InstEmit.Vmnmx,   typeof(OpCodeVideo));
             Set("0101000011011x", InstEmit.Vote,    typeof(OpCodeVote));
             Set("0100111xxxxxxx", InstEmit.Xmad,    typeof(OpCodeAluCbuf));
             Set("0011011x00xxxx", InstEmit.Xmad,    typeof(OpCodeAluImm));
diff --git a/Ryujinx.Graphics.Shader/Decoders/OpCodeVideo.cs b/Ryujinx.Graphics.Shader/Decoders/OpCodeVideo.cs
index 15dcfa98..c2bdc22f 100644
--- a/Ryujinx.Graphics.Shader/Decoders/OpCodeVideo.cs
+++ b/Ryujinx.Graphics.Shader/Decoders/OpCodeVideo.cs
@@ -6,19 +6,98 @@ namespace Ryujinx.Graphics.Shader.Decoders
     {
         public Register Rd { get; }
         public Register Ra { get; }
+        public Register Rb { get; }
         public Register Rc { get; }
 
-        public bool SetCondCode { get; protected set; }
-        public bool Saturate    { get; protected set; }
+        public int Immediate { get; }
+
+        public int RaSelection { get; }
+        public int RbSelection { get; }
+
+        public bool SetCondCode { get; }
+
+        public bool HasRb { get; }
+
+        public VideoType RaType { get; }
+        public VideoType RbType { get; }
+
+        public VideoPostOp PostOp { get; }
+
+        public bool DstSigned { get; }
+        public bool Saturate  { get; }
 
         public OpCodeVideo(InstEmitter emitter, ulong address, long opCode) : base(emitter, address, opCode)
         {
             Rd = new Register(opCode.Extract(0,  8), RegisterType.Gpr);
             Ra = new Register(opCode.Extract(8,  8), RegisterType.Gpr);
+            Rb = new Register(opCode.Extract(20, 8), RegisterType.Gpr);
             Rc = new Register(opCode.Extract(39, 8), RegisterType.Gpr);
 
+            RaSelection = opCode.Extract(36, 2);
+            RbSelection = opCode.Extract(28, 2);
+
+            RaType = opCode.Extract(37, 2) switch
+            {
+                2 => VideoType.U16,
+                3 => VideoType.U32,
+                _ => VideoType.U8
+            };
+
+            RbType = opCode.Extract(29, 2) switch
+            {
+                2 => VideoType.U16,
+                3 => VideoType.U32,
+                _ => VideoType.U8
+            };
+
+            if (opCode.Extract(48))
+            {
+                RaType |= VideoType.Signed;
+            }
+
+            if (!opCode.Extract(50))
+            {
+                // Immediate variant.
+                Immediate = opCode.Extract(16, 20);
+
+                RbType = opCode.Extract(49) ? VideoType.S16 : VideoType.U16;
+
+                if (RbType == VideoType.S16)
+                {
+                    Immediate = (Immediate << 12) >> 12;
+                }
+            }
+            else if (opCode.Extract(49))
+            {
+                RbType |= VideoType.Signed;
+            }
+
+            if (RaType == VideoType.U16)
+            {
+                RaSelection &= 1;
+            }
+            else if (RaType == VideoType.U32)
+            {
+                RaSelection = 0;
+            }
+
+            if (RbType == VideoType.U16)
+            {
+                RbSelection &= 1;
+            }
+            else if (RbType == VideoType.U32)
+            {
+                RbSelection = 0;
+            }
+
             SetCondCode = opCode.Extract(47);
-            Saturate    = opCode.Extract(55);
+
+            HasRb = opCode.Extract(50);
+
+            PostOp = (VideoPostOp)opCode.Extract(51, 3);
+
+            DstSigned = opCode.Extract(54);
+            Saturate  = opCode.Extract(55);
         }
     }
 }
\ No newline at end of file
diff --git a/Ryujinx.Graphics.Shader/Decoders/VideoPostOp.cs b/Ryujinx.Graphics.Shader/Decoders/VideoPostOp.cs
new file mode 100644
index 00000000..65891789
--- /dev/null
+++ b/Ryujinx.Graphics.Shader/Decoders/VideoPostOp.cs
@@ -0,0 +1,14 @@
+namespace Ryujinx.Graphics.Shader.Decoders
+{
+    enum VideoPostOp
+    {
+        Mrg16h,
+        Mrg16l,
+        Mrg8b0,
+        Mrg8b2,
+        Acc,
+        Min,
+        Max,
+        Pass
+    }
+}
diff --git a/Ryujinx.Graphics.Shader/Decoders/VideoType.cs b/Ryujinx.Graphics.Shader/Decoders/VideoType.cs
new file mode 100644
index 00000000..7186e7c3
--- /dev/null
+++ b/Ryujinx.Graphics.Shader/Decoders/VideoType.cs
@@ -0,0 +1,15 @@
+namespace Ryujinx.Graphics.Shader.Decoders
+{
+    enum VideoType
+    {
+        U8  = 0,
+        U16 = 1,
+        U32 = 2,
+
+        Signed = 1 << 2,
+
+        S8  = Signed | U8,
+        S16 = Signed | U16,
+        S32 = Signed | U32
+    }
+}
diff --git a/Ryujinx.Graphics.Shader/Instructions/InstEmitVideo.cs b/Ryujinx.Graphics.Shader/Instructions/InstEmitVideo.cs
index aac12c78..7b3d9ca5 100644
--- a/Ryujinx.Graphics.Shader/Instructions/InstEmitVideo.cs
+++ b/Ryujinx.Graphics.Shader/Instructions/InstEmitVideo.cs
@@ -1,7 +1,9 @@
 using Ryujinx.Graphics.Shader.Decoders;
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
 using Ryujinx.Graphics.Shader.Translation;
 
 using static Ryujinx.Graphics.Shader.Instructions.InstEmitHelper;
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
 
 namespace Ryujinx.Graphics.Shader.Instructions
 {
@@ -9,9 +11,126 @@ namespace Ryujinx.Graphics.Shader.Instructions
     {
         public static void Vmad(EmitterContext context)
         {
+            // TODO: Implement properly.
+            context.Copy(GetDest(context), GetSrcC(context));
+        }
+
+        public static void Vmnmx(EmitterContext context)
+        {
             OpCodeVideo op = (OpCodeVideo)context.CurrOp;
 
-            context.Copy(GetDest(context), GetSrcC(context));
+            bool max = op.RawOpCode.Extract(56);
+
+            Operand srcA = Extend(context, GetSrcA(context), op.RaSelection, op.RaType);
+            Operand srcC = GetSrcC(context);
+
+            Operand srcB;
+
+            if (op.HasRb)
+            {
+                srcB = Extend(context, Register(op.Rb), op.RbSelection, op.RbType);
+            }
+            else
+            {
+                srcB = Const(op.Immediate);
+            }
+
+            Operand res;
+
+            bool resSigned;
+
+            if ((op.RaType & VideoType.Signed) != (op.RbType & VideoType.Signed))
+            {
+                // Signedness is different, but for max, result will always fit a U32,
+                // since one of the inputs can't be negative, and the result is the one
+                // with highest value. For min, it will always fit on a S32, since
+                // one of the input can't be greater than INT_MAX and we want the lowest value.
+                resSigned = !max;
+
+                res = max ? context.IMaximumU32(srcA, srcB) : context.IMinimumS32(srcA, srcB);
+
+                if ((op.RaType & VideoType.Signed) != 0)
+                {
+                    Operand isBGtIntMax = context.ICompareLess(srcB, Const(0));
+
+                    res = context.ConditionalSelect(isBGtIntMax, srcB, res);
+                }
+                else
+                {
+                    Operand isAGtIntMax = context.ICompareLess(srcA, Const(0));
+
+                    res = context.ConditionalSelect(isAGtIntMax, srcA, res);
+                }
+            }
+            else
+            {
+                // Ra and Rb have the same signedness, so doesn't matter which one we test.
+                resSigned = (op.RaType & VideoType.Signed) != 0;
+
+                if (max)
+                {
+                    res = resSigned
+                        ? context.IMaximumS32(srcA, srcB)
+                        : context.IMaximumU32(srcA, srcB);
+                }
+                else
+                {
+                    res = resSigned
+                        ? context.IMinimumS32(srcA, srcB)
+                        : context.IMinimumU32(srcA, srcB);
+                }
+            }
+
+            if (op.Saturate)
+            {
+                if (op.DstSigned && !resSigned)
+                {
+                    res = context.IMinimumU32(res, Const(int.MaxValue));
+                }
+                else if (!op.DstSigned && resSigned)
+                {
+                    res = context.IMaximumS32(res, Const(0));
+                }
+            }
+
+            switch (op.PostOp)
+            {
+                case VideoPostOp.Acc:
+                    res = context.IAdd(res, srcC);
+                    break;
+                case VideoPostOp.Max:
+                    res = op.DstSigned ? context.IMaximumS32(res, srcC) : context.IMaximumU32(res, srcC);
+                    break;
+                case VideoPostOp.Min:
+                    res = op.DstSigned ? context.IMinimumS32(res, srcC) : context.IMinimumU32(res, srcC);
+                    break;
+                case VideoPostOp.Mrg16h:
+                    res = context.BitfieldInsert(srcC, res, Const(16), Const(16));
+                    break;
+                case VideoPostOp.Mrg16l:
+                    res = context.BitfieldInsert(srcC, res, Const(0), Const(16));
+                    break;
+                case VideoPostOp.Mrg8b0:
+                    res = context.BitfieldInsert(srcC, res, Const(0), Const(8));
+                    break;
+                case VideoPostOp.Mrg8b2:
+                    res = context.BitfieldInsert(srcC, res, Const(16), Const(8));
+                    break;
+            }
+
+            context.Copy(GetDest(context), res);
+        }
+
+        private static Operand Extend(EmitterContext context, Operand src, int sel, VideoType type)
+        {
+            return type switch
+            {
+                VideoType.U8  => ZeroExtendTo32(context, context.ShiftRightU32(src, Const(sel * 8)),  8),
+                VideoType.U16 => ZeroExtendTo32(context, context.ShiftRightU32(src, Const(sel * 16)), 16),
+                VideoType.S8  => SignExtendTo32(context, context.ShiftRightU32(src, Const(sel * 8)),  8),
+                VideoType.S16 => SignExtendTo32(context, context.ShiftRightU32(src, Const(sel * 16)), 16),
+                _ => src
+            };
         }
     }
 }
\ No newline at end of file