From d93cdc27505f86633d3a947fb48a6bcb92d790d0 Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Mon, 15 Oct 2018 02:07:16 -0300
Subject: gl_shader_decompiler: Implement HADD2_IMM and HMUL2_IMM

---
 .../renderer_opengl/gl_shader_decompiler.cpp       | 43 ++++++++++++++++++++++
 1 file changed, 43 insertions(+)

(limited to 'src/video_core/renderer_opengl')

diff --git a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
index a1a0babe8..ab30aafc3 100644
--- a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
@@ -920,6 +920,19 @@ private:
         return fmt::format("uintBitsToFloat({})", instr.alu.GetImm20_32());
     }
 
+    /// Generates code representing a vec2 pair unpacked from a half float immediate
+    static std::string UnpackHalfImmediate(const Instruction& instr, bool negate) {
+        const std::string immediate = GetHalfFloat(std::to_string(instr.half_imm.PackImmediates()));
+        if (!negate) {
+            return immediate;
+        }
+        const std::string negate_first = instr.half_imm.first_negate != 0 ? "-" : "";
+        const std::string negate_second = instr.half_imm.second_negate != 0 ? "-" : "";
+        const std::string negate_vec = "vec2(" + negate_first + "1, " + negate_second + "1)";
+
+        return '(' + immediate + " * " + negate_vec + ')';
+    }
+
     /// Generates code representing a texture sampler.
     std::string GetSampler(const Sampler& sampler, Tegra::Shader::TextureType type, bool is_array,
                            bool is_shadow) {
@@ -1877,6 +1890,36 @@ private:
                                         instr.alu_half.saturate != 0);
             break;
         }
+        case OpCode::Type::ArithmeticHalfImmediate: {
+            if (opcode->GetId() == OpCode::Id::HADD2_IMM) {
+                ASSERT_MSG(instr.alu_half_imm.ftz == 0, "Unimplemented");
+            } else {
+                ASSERT_MSG(instr.alu_half_imm.precision == Tegra::Shader::HalfPrecision::None,
+                           "Unimplemented");
+            }
+
+            const std::string op_a = GetHalfFloat(
+                regs.GetRegisterAsInteger(instr.gpr8, 0, false), instr.alu_half_imm.type_a,
+                instr.alu_half_imm.abs_a != 0, instr.alu_half_imm.negate_a != 0);
+
+            const std::string op_b = UnpackHalfImmediate(instr, true);
+
+            const std::string result = [&]() {
+                switch (opcode->GetId()) {
+                case OpCode::Id::HADD2_IMM:
+                    return op_a + " + " + op_b;
+                case OpCode::Id::HMUL2_IMM:
+                    return op_a + " * " + op_b;
+                default:
+                    UNREACHABLE();
+                    return std::string("0");
+                }
+            }();
+
+            regs.SetRegisterToHalfFloat(instr.gpr0, 0, result, instr.alu_half_imm.merge, 1, 1,
+                                        instr.alu_half_imm.saturate != 0);
+            break;
+        }
         case OpCode::Type::Ffma: {
             const std::string op_a = regs.GetRegisterAsFloat(instr.gpr8);
             std::string op_b = instr.ffma.negate_b ? "-" : "";
-- 
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