3 files changed, 28 insertions, 4 deletions

diff --git a/src/shader_recompiler/backend/glasm/emit_glasm.cpp b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
index 4fc7d2f2f..f110fd7f8 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
@@ -281,7 +281,8 @@ void SetupOptions(const IR::Program& program, const Profile& profile, std::strin
     if (info.uses_atomic_f16x2_add || info.uses_atomic_f16x2_min || info.uses_atomic_f16x2_max) {
         header += "OPTION NV_shader_atomic_fp16_vector;";
     }
-    if (info.uses_subgroup_invocation_id || info.uses_subgroup_mask || info.uses_subgroup_vote) {
+    if (info.uses_subgroup_invocation_id || info.uses_subgroup_mask || info.uses_subgroup_vote ||
+        info.uses_fswzadd) {
         header += "OPTION NV_shader_thread_group;";
     }
     if (info.uses_subgroup_shuffles) {
@@ -416,12 +417,25 @@ std::string EmitGLASM(const Profile& profile, IR::Program& program, Bindings& bi
     if (program.local_memory_size > 0) {
         header += fmt::format("lmem[{}],", program.local_memory_size);
     }
+    if (program.info.uses_fswzadd) {
+        header += "FSWZA[4],FSWZB[4],";
+    }
     header += "RC;"
               "LONG TEMP ";
     for (size_t index = 0; index < ctx.reg_alloc.NumUsedLongRegisters(); ++index) {
         header += fmt::format("D{},", index);
     }
     header += "DC;";
+    if (program.info.uses_fswzadd) {
+        header += "MOV.F FSWZA[0],-1;"
+                  "MOV.F FSWZA[1],1;"
+                  "MOV.F FSWZA[2],-1;"
+                  "MOV.F FSWZA[3],0;"
+                  "MOV.F FSWZB[0],-1;"
+                  "MOV.F FSWZB[1],-1;"
+                  "MOV.F FSWZB[2],1;"
+                  "MOV.F FSWZB[3],-1;";
+    }
     ctx.code.insert(0, header);
     ctx.code += "END";
     return ctx.code;
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h b/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
index 2eb1eb123..15380a955 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
@@ -616,7 +616,8 @@ void EmitShuffleDown(EmitContext& ctx, IR::Inst& inst, ScalarU32 value, ScalarU3
                      const IR::Value& clamp, const IR::Value& segmentation_mask);
 void EmitShuffleButterfly(EmitContext& ctx, IR::Inst& inst, ScalarU32 value, ScalarU32 index,
                           const IR::Value& clamp, const IR::Value& segmentation_mask);
-void EmitFSwizzleAdd(EmitContext& ctx, ScalarF32 op_a, ScalarF32 op_b, ScalarU32 swizzle);
+void EmitFSwizzleAdd(EmitContext& ctx, IR::Inst& inst, ScalarF32 op_a, ScalarF32 op_b,
+                     ScalarU32 swizzle);
 void EmitDPdxFine(EmitContext& ctx, IR::Inst& inst, ScalarF32 op_a);
 void EmitDPdyFine(EmitContext& ctx, IR::Inst& inst, ScalarF32 op_a);
 void EmitDPdxCoarse(EmitContext& ctx, IR::Inst& inst, ScalarF32 op_a);
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_warp.cpp b/src/shader_recompiler/backend/glasm/emit_glasm_warp.cpp
index 0f987daeb..af0e13d43 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_warp.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_warp.cpp
@@ -95,8 +95,17 @@ void EmitShuffleButterfly(EmitContext& ctx, IR::Inst& inst, ScalarU32 value, Sca
     Shuffle(ctx, inst, value, index, clamp, segmentation_mask, "XOR");
 }
 
-void EmitFSwizzleAdd(EmitContext&, ScalarF32, ScalarF32, ScalarU32) {
-    throw NotImplementedException("GLASM instruction");
+void EmitFSwizzleAdd(EmitContext& ctx, IR::Inst& inst, ScalarF32 op_a, ScalarF32 op_b,
+                     ScalarU32 swizzle) {
+    const auto ret{ctx.reg_alloc.Define(inst)};
+    ctx.Add("AND.U RC.z,{}.threadid,3;"
+            "SHL.U RC.z,RC.z,1;"
+            "SHR.U RC.z,{},RC.z;"
+            "AND.U RC.z,RC.z,3;"
+            "MUL.F RC.x,{},FSWZA[RC.z];"
+            "MUL.F RC.y,{},FSWZB[RC.z];"
+            "ADD.F {}.x,RC.x,RC.y;",
+            ctx.stage_name, swizzle, op_a, op_b, ret);
 }
 
 void EmitDPdxFine(EmitContext& ctx, IR::Inst& inst, ScalarF32 p) {