From d1e62b99932a3404a4a9ad641ebcf2711af7eb5b Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Mon, 3 May 2021 22:33:37 +0100
Subject: [PATCH] T32: Add VFP instructions

---
 .../A32/translate/translate_thumb.cpp         | 13 ++++++++++
 tests/A32/fuzz_arm.cpp                        | 24 +++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/src/frontend/A32/translate/translate_thumb.cpp b/src/frontend/A32/translate/translate_thumb.cpp
index 1f2f41b6..9f93c11d 100644
--- a/src/frontend/A32/translate/translate_thumb.cpp
+++ b/src/frontend/A32/translate/translate_thumb.cpp
@@ -11,6 +11,7 @@
 #include "common/bit_util.h"
 #include "frontend/A32/decoder/thumb16.h"
 #include "frontend/A32/decoder/thumb32.h"
+#include "frontend/A32/decoder/vfp.h"
 #include "frontend/A32/ir_emitter.h"
 #include "frontend/A32/location_descriptor.h"
 #include "frontend/A32/translate/conditional_state.h"
@@ -88,6 +89,12 @@ IR::Block TranslateThumb(LocationDescriptor descriptor, MemoryReadCodeFuncType m
             } else {
                 if (const auto decoder = DecodeThumb32<TranslatorVisitor>(thumb_instruction)) {
                     should_continue = decoder->get().call(visitor, thumb_instruction);
+                } else if ((thumb_instruction & 0xEC000000) == 0xEC000000) {
+                    if (const auto vfp_decoder = DecodeVFP<TranslatorVisitor>(thumb_instruction)) {
+                        should_continue = vfp_decoder->get().call(visitor, thumb_instruction);
+                    } else {
+                        should_continue = visitor.thumb32_UDF();
+                    }
                 } else {
                     should_continue = visitor.thumb32_UDF();
                 }
@@ -134,6 +141,12 @@ bool TranslateSingleThumbInstruction(IR::Block& block, LocationDescriptor descri
         thumb_instruction = Common::SwapHalves32(thumb_instruction);
         if (const auto decoder = DecodeThumb32<TranslatorVisitor>(thumb_instruction)) {
             should_continue = decoder->get().call(visitor, thumb_instruction);
+        } else if ((thumb_instruction & 0xEC000000) == 0xEC000000) {
+            if (const auto vfp_decoder = DecodeVFP<TranslatorVisitor>(thumb_instruction)) {
+                should_continue = vfp_decoder->get().call(visitor, thumb_instruction);
+            } else {
+                should_continue = visitor.thumb32_UDF();
+            }
         } else {
             should_continue = visitor.thumb32_UDF();
         }
diff --git a/tests/A32/fuzz_arm.cpp b/tests/A32/fuzz_arm.cpp
index 89ec80bc..8dcbf7ed 100644
--- a/tests/A32/fuzz_arm.cpp
+++ b/tests/A32/fuzz_arm.cpp
@@ -158,6 +158,12 @@ std::vector<u16> GenRandomThumbInst(u32 pc, bool is_last_inst, A32::ITState it_s
 #undef INST
         };
 
+        const std::vector<std::tuple<std::string, const char*>> vfp_list {
+#define INST(fn, name, bitstring) {#fn, bitstring},
+#include "frontend/A32/decoder/vfp.inc"
+#undef INST
+        };
+
         std::vector<InstructionGenerator> generators;
         std::vector<InstructionGenerator> invalid;
 
@@ -176,6 +182,13 @@ std::vector<u16> GenRandomThumbInst(u32 pc, bool is_last_inst, A32::ITState it_s
             "thumb32_STREXB",
             "thumb32_STREXD",
             "thumb32_STREXH",
+
+            // FPSCR is inaccurate
+            "vfp_VMRS",
+
+            // Unicorn has incorrect implementation (incorrect rounding and unsets CPSR.T??)
+            "vfp_VCVT_to_fixed",
+            "vfp_VCVT_from_fixed",
         };
 
         for (const auto& [fn, bitstring] : list) {
@@ -185,6 +198,17 @@ std::vector<u16> GenRandomThumbInst(u32 pc, bool is_last_inst, A32::ITState it_s
             }
             generators.emplace_back(InstructionGenerator{bitstring});
         }
+        for (const auto& [fn, bs] : vfp_list) {
+            std::string bitstring = bs;
+            if (bitstring.substr(0, 4) == "cccc" || bitstring.substr(0, 4) == "----") {
+                bitstring.replace(0, 4, "1110");
+            }
+            if (std::find(do_not_test.begin(), do_not_test.end(), fn) != do_not_test.end()) {
+                invalid.emplace_back(InstructionGenerator{bitstring.c_str()});
+                continue;
+            }
+            generators.emplace_back(InstructionGenerator{bitstring.c_str()});
+        }
         return InstructionGeneratorInfo{generators, invalid};
     }();