[dynarmic] unconditional branches always take

Signed-off-by: lizzie <lizzie@eden-emu.dev>

src/dynarmic/src/dynarmic/backend/x64/block_of_code.cpp

@@ -364,8 +364,7 @@ void BlockOfCode::GenRunCode(std::function<void(BlockOfCode&)> rcp) {
 
     cmp(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], 0);
     jne(return_to_caller_mxcsr_already_exited, T_NEAR);
-    lock();
-    or_(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], static_cast<u32>(HaltReason::Step));
+    lock(); or_(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], static_cast<u32>(HaltReason::Step));
 
     SwitchMxcsrOnEntry();
     jmp(ABI_PARAM2);
@@ -415,7 +414,6 @@ void BlockOfCode::GenRunCode(std::function<void(BlockOfCode&)> rcp) {
     }
 
     xor_(eax, eax);
-    lock();
     xchg(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], eax);
 
     ABI_PopCalleeSaveRegistersAndAdjustStack(*this, sizeof(StackLayout));

src/dynarmic/src/dynarmic/backend/x64/reg_alloc.cpp

@@ -9,6 +9,7 @@
 #include "dynarmic/backend/x64/reg_alloc.h"
 
 #include <algorithm>
+#include <limits>
 #include <numeric>
 #include <utility>
 
@@ -152,19 +153,19 @@ bool Argument::GetImmediateU1() const noexcept {
 
 u8 Argument::GetImmediateU8() const noexcept {
     const u64 imm = value.GetImmediateAsU64();
-    ASSERT(imm < 0x100);
+    ASSERT(imm <= u64(std::numeric_limits<u8>::max()));
     return u8(imm);
 }
 
 u16 Argument::GetImmediateU16() const noexcept {
     const u64 imm = value.GetImmediateAsU64();
-    ASSERT(imm < 0x10000);
+    ASSERT(imm <= u64(std::numeric_limits<u16>::max()));
     return u16(imm);
 }
 
 u32 Argument::GetImmediateU32() const noexcept {
     const u64 imm = value.GetImmediateAsU64();
-    ASSERT(imm < 0x100000000);
+    ASSERT(imm <= u64(std::numeric_limits<u32>::max()));
     return u32(imm);
 }
 

src/dynarmic/src/dynarmic/frontend/A64/translate/impl/a64_branch.cpp

@@ -20,9 +20,12 @@ bool TranslatorVisitor::B_cond(Imm<19> imm19, Cond cond) {
 bool TranslatorVisitor::B_uncond(Imm<26> imm26) {
     const s64 offset = concatenate(imm26, Imm<2>{0}).SignExtend<s64>();
     const u64 target = ir.PC() + offset;
-
-    //ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location->SetPC(target)});
-    ir.SetTerm(IR::Term::LinkBlock{ir.current_location->SetPC(target)});
+    // Pattern to halt execution (B .)
+    if (target == ir.PC()) {
+        ir.SetTerm(IR::Term::LinkBlock{ir.current_location->SetPC(target)});
+        return false;
+    }
+    ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location->SetPC(target)});
     return false;
 }