From bce0b1dcca4e83ab8bb6692e98d021ded5c0ad5f Mon Sep 17 00:00:00 2001
From: ameerj <52414509+ameerj@users.noreply.github.com>
Date: Mon, 1 Mar 2021 00:18:30 -0500
Subject: [PATCH] shader: Implement ICMP

---
 src/shader_recompiler/CMakeLists.txt          |  1 +
 .../translate/impl/integer_compare.cpp        | 83 +++++++++++++++++++
 .../translate/impl/not_implemented.cpp        | 16 ----
 3 files changed, 84 insertions(+), 16 deletions(-)
 create mode 100644 src/shader_recompiler/frontend/maxwell/translate/impl/integer_compare.cpp

diff --git a/src/shader_recompiler/CMakeLists.txt b/src/shader_recompiler/CMakeLists.txt
index e0568a0580..a227ce21b0 100644
--- a/src/shader_recompiler/CMakeLists.txt
+++ b/src/shader_recompiler/CMakeLists.txt
@@ -71,6 +71,7 @@ add_library(shader_recompiler STATIC
     frontend/maxwell/translate/impl/impl.cpp
     frontend/maxwell/translate/impl/impl.h
     frontend/maxwell/translate/impl/integer_add.cpp
+    frontend/maxwell/translate/impl/integer_compare.cpp
     frontend/maxwell/translate/impl/integer_minimum_maximum.cpp
     frontend/maxwell/translate/impl/integer_popcount.cpp
     frontend/maxwell/translate/impl/integer_scaled_add.cpp
diff --git a/src/shader_recompiler/frontend/maxwell/translate/impl/integer_compare.cpp b/src/shader_recompiler/frontend/maxwell/translate/impl/integer_compare.cpp
new file mode 100644
index 0000000000..1f604b0ee8
--- /dev/null
+++ b/src/shader_recompiler/frontend/maxwell/translate/impl/integer_compare.cpp
@@ -0,0 +1,83 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/bit_field.h"
+#include "common/common_types.h"
+#include "shader_recompiler/frontend/maxwell/translate/impl/impl.h"
+
+namespace Shader::Maxwell {
+namespace {
+enum class ComparisonOp : u64 {
+    False,
+    LessThan,
+    Equal,
+    LessThanEqual,
+    GreaterThan,
+    NotEqual,
+    GreaterThanEqual,
+    True,
+};
+
+[[nodiscard]] IR::U1 CompareToZero(TranslatorVisitor& v, const IR::U32& operand,
+                                   ComparisonOp compare_op, bool is_signed) {
+    const IR::U32 zero{v.ir.Imm32(0)};
+    switch (compare_op) {
+    case ComparisonOp::False:
+        return v.ir.Imm1(false);
+    case ComparisonOp::LessThan:
+        return v.ir.ILessThan(operand, zero, is_signed);
+    case ComparisonOp::Equal:
+        return v.ir.IEqual(operand, zero);
+    case ComparisonOp::LessThanEqual:
+        return v.ir.ILessThanEqual(operand, zero, is_signed);
+    case ComparisonOp::GreaterThan:
+        return v.ir.IGreaterThan(operand, zero, is_signed);
+    case ComparisonOp::NotEqual:
+        return v.ir.INotEqual(operand, zero);
+    case ComparisonOp::GreaterThanEqual:
+        return v.ir.IGreaterThanEqual(operand, zero, is_signed);
+    case ComparisonOp::True:
+        return v.ir.Imm1(true);
+    default:
+        throw NotImplementedException("ICMP.CMP");
+    }
+}
+
+void ICMP(TranslatorVisitor& v, u64 insn, const IR::U32& src_a, const IR::U32& operand) {
+    union {
+        u64 insn;
+        BitField<0, 8, IR::Reg> dest_reg;
+        BitField<8, 8, IR::Reg> src_reg;
+        BitField<48, 1, u64> is_signed;
+        BitField<49, 3, ComparisonOp> compare_op;
+    } const icmp{insn};
+
+    const IR::U32 zero{v.ir.Imm32(0)};
+    const bool is_signed{icmp.is_signed != 0};
+    const IR::U1 cmp_result{CompareToZero(v, operand, icmp.compare_op, is_signed)};
+
+    const IR::U32 src_reg{v.X(icmp.src_reg)};
+    const IR::U32 result{v.ir.Select(cmp_result, src_reg, src_a)};
+
+    v.X(icmp.dest_reg, result);
+}
+} // Anonymous namespace
+
+void TranslatorVisitor::ICMP_reg(u64 insn) {
+    ICMP(*this, insn, GetReg20(insn), GetReg39(insn));
+}
+
+void TranslatorVisitor::ICMP_rc(u64 insn) {
+    ICMP(*this, insn, GetReg39(insn), GetCbuf(insn));
+}
+
+void TranslatorVisitor::ICMP_cr(u64 insn) {
+    ICMP(*this, insn, GetCbuf(insn), GetReg39(insn));
+}
+
+void TranslatorVisitor::ICMP_imm(u64 insn) {
+    ICMP(*this, insn, GetImm20(insn), GetReg39(insn));
+}
+
+} // namespace Shader::Maxwell
diff --git a/src/shader_recompiler/frontend/maxwell/translate/impl/not_implemented.cpp b/src/shader_recompiler/frontend/maxwell/translate/impl/not_implemented.cpp
index 615e3c3b5b..8d4044ee86 100644
--- a/src/shader_recompiler/frontend/maxwell/translate/impl/not_implemented.cpp
+++ b/src/shader_recompiler/frontend/maxwell/translate/impl/not_implemented.cpp
@@ -389,22 +389,6 @@ void TranslatorVisitor::IADD3_imm(u64) {
     ThrowNotImplemented(Opcode::IADD3_imm);
 }
 
-void TranslatorVisitor::ICMP_reg(u64) {
-    ThrowNotImplemented(Opcode::ICMP_reg);
-}
-
-void TranslatorVisitor::ICMP_rc(u64) {
-    ThrowNotImplemented(Opcode::ICMP_rc);
-}
-
-void TranslatorVisitor::ICMP_cr(u64) {
-    ThrowNotImplemented(Opcode::ICMP_cr);
-}
-
-void TranslatorVisitor::ICMP_imm(u64) {
-    ThrowNotImplemented(Opcode::ICMP_imm);
-}
-
 void TranslatorVisitor::IDE(u64) {
     ThrowNotImplemented(Opcode::IDE);
 }