Small fixes for better cross-platform compatibility (#200)

* Add ifdef check before the Microsoft-specific movsq in memory.cc

* Added ifdef before Microsoft-specific movsq and replaced with memcpy in other cases. In memory.cc

* Update image_sha_bytes_ from 16 to 20  xex_module.h

The value 16 is less than the expected value 20, causing a buffer overflow during sha1 finalization.

* Update image_sha_bytes_ loop from 16 to 20 iterations xex_module.cc

* Update mapped_memory_posix.cc: Must resize file to map_length.

* Should not map nullptr with MAP_FIXED flag. Update memory_posix.cc.

src/xenia/base/mapped_memory_posix.cc

@@ -58,6 +58,7 @@ class PosixMappedMemory : public MappedMemory {
 
     void* data =
         mmap(0, map_length, protection, MAP_SHARED, file_descriptor, offset);
+    ftruncate(file_descriptor, map_length);
     if (!data) {
       close(file_descriptor);
       return nullptr;

src/xenia/base/memory.cc

@@ -176,8 +176,12 @@ static void vastcpy_impl_movdir64m(CacheLine* XE_RESTRICT physaddr,
 static void vastcpy_impl_repmovs(CacheLine* XE_RESTRICT physaddr,
                                  CacheLine* XE_RESTRICT rdmapping,
                                  uint32_t written_length) {
+#if XE_ARCH_AMD64 == 1 && XE_COMPILER_MSVC == 1
   __movsq((unsigned long long*)physaddr, (unsigned long long*)rdmapping,
           written_length / 8);
+#else
+  memcpy((unsigned char*)physaddr, (const unsigned char*)rdmapping, written_length);
+#endif
 }
 XE_COLD
 static void first_vastcpy(CacheLine* XE_RESTRICT physaddr,

src/xenia/base/memory_posix.cc

@@ -85,6 +85,12 @@ void* AllocFixed(void* base_address, size_t length,
                  AllocationType allocation_type, PageAccess access) {
   // mmap does not support reserve / commit, so ignore allocation_type.
   uint32_t prot = ToPosixProtectFlags(access);
+  int flags = 0;
+  if (base_address != nullptr) {
+    flags = MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS;
+  } else {
+    flags = MAP_PRIVATE | MAP_ANONYMOUS;
+  }
   void* result = mmap(base_address, length, prot,
                       MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
   if (result == MAP_FAILED) {

src/xenia/cpu/xex_module.cc

@@ -1120,7 +1120,7 @@ void XexModule::Precompile() {
 
   char fmtbuf[16];
 
-  for (unsigned i = 0; i < 16; ++i) {
+  for (unsigned i = 0; i < 20; ++i) {
     sprintf_s(fmtbuf, "%X", image_sha_bytes_[i]);
     image_sha_str_ += &fmtbuf[0];
   }

src/xenia/cpu/xex_module.h

@@ -282,7 +282,7 @@ class XexModule : public xe::cpu::Module {
   XexFormat xex_format_ = kFormatUnknown;
   SecurityInfoContext security_info_ = {};
 
-  uint8_t image_sha_bytes_[16];
+  uint8_t image_sha_bytes_[20];
   std::string image_sha_str_;
   XexInfoCache info_cache_;
 };