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[dynarmic] use LinkBlockFast for branches which are guarnateed to be unconditional (or conditionally unconditional) (#4177)

CBZ is basically
```c
if (thing) {
  jump(A);
} else  {
 jump(B);
}
```
those jumps are locally unconditional so we can add the LinkBlockFast
without much repercussions for a small win in JIT opts

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

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4177
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
lizzie/maxwell-use-params-instead-of-template
lizzie 3 days ago
committed by crueter
parent
commit
f22fd1714b
No known key found for this signature in database GPG Key ID: 425ACD2D4830EBC6
  1. 5
      docs/dynarmic/Design.md
  2. 12
      src/dynarmic/src/dynarmic/frontend/A32/translate/impl/a32_branch.cpp
  3. 5
      src/dynarmic/src/dynarmic/frontend/A32/translate/impl/status_register_access.cpp
  4. 21
      src/dynarmic/src/dynarmic/frontend/A32/translate/impl/thumb16.cpp
  5. 37
      src/dynarmic/src/dynarmic/frontend/A32/translate/impl/thumb32_branch.cpp
  6. 24
      src/dynarmic/src/dynarmic/frontend/A64/translate/impl/a64_branch.cpp

5
docs/dynarmic/Design.md

@ -311,8 +311,9 @@ dispatcher, which will return control to the host.
SetTerm(IR::Term::LinkBlockFast{next})
```
This terminal instruction jumps to the basic block described by `next` unconditionally.
This promises guarantees that must be held at runtime - i.e that the program wont hang,
This terminal instruction jumps to the basic block described by `next` unconditionally. This promises guarantees that must be held at runtime - i.e that the program wont hang,
This is a valid expression if contained within another block (say a `Terminal::If`) and the semantics allow it to be so.
### Terminal: PopRSBHint

12
src/dynarmic/src/dynarmic/frontend/A32/translate/impl/a32_branch.cpp

@ -17,10 +17,14 @@ bool TranslatorVisitor::arm_B(Cond cond, Imm<24> imm24) {
if (!ArmConditionPassed(cond)) {
return true;
}
const u32 imm32 = mcl::bit::sign_extend<26, u32>(imm24.ZeroExtend() << 2) + 8;
const auto new_location = ir.current_location.AdvancePC(imm32);
ir.SetTerm(IR::Term::LinkBlock{new_location});
// pattern match => b .
if (imm32 == 0) {
ir.SetTerm(IR::Term::LinkBlock{new_location});
} else {
ir.SetTerm(IR::Term::LinkBlockFast{new_location});
}
return false;
}
@ -35,7 +39,7 @@ bool TranslatorVisitor::arm_BL(Cond cond, Imm<24> imm24) {
const u32 imm32 = mcl::bit::sign_extend<26, u32>(imm24.ZeroExtend() << 2) + 8;
const auto new_location = ir.current_location.AdvancePC(imm32);
ir.SetTerm(IR::Term::LinkBlock{new_location});
ir.SetTerm(IR::Term::LinkBlockFast{new_location});
return false;
}
@ -46,7 +50,7 @@ bool TranslatorVisitor::arm_BLX_imm(bool H, Imm<24> imm24) {
const u32 imm32 = mcl::bit::sign_extend<26, u32>((imm24.ZeroExtend() << 2)) + (H ? 2 : 0) + 8;
const auto new_location = ir.current_location.AdvancePC(imm32).SetTFlag(true);
ir.SetTerm(IR::Term::LinkBlock{new_location});
ir.SetTerm(IR::Term::LinkBlockFast{new_location});
return false;
}

5
src/dynarmic/src/dynarmic/frontend/A32/translate/impl/status_register_access.cpp

@ -56,11 +56,10 @@ bool TranslatorVisitor::arm_MSR_imm(Cond cond, unsigned mask, int rotate, Imm<8>
if (write_e) {
const bool E = (imm32 & 0x00000200) != 0;
if (E != ir.current_location.EFlag()) {
ir.SetTerm(IR::Term::LinkBlock{ir.current_location.AdvancePC(4).SetEFlag(E)});
ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location.AdvancePC(4).SetEFlag(E)});
return false;
}
}
return true;
}
@ -112,7 +111,7 @@ bool TranslatorVisitor::arm_RFE() {
// SETEND <endian_specifier>
bool TranslatorVisitor::arm_SETEND(bool E) {
ir.SetTerm(IR::Term::LinkBlock{ir.current_location.AdvancePC(4).SetEFlag(E)});
ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location.AdvancePC(4).SetEFlag(E)});
return false;
}

21
src/dynarmic/src/dynarmic/frontend/A32/translate/impl/thumb16.cpp

@ -803,7 +803,7 @@ bool TranslatorVisitor::thumb16_SETEND(bool E) {
return true;
}
ir.SetTerm(IR::Term::LinkBlock{ir.current_location.AdvancePC(2).SetEFlag(E).AdvanceIT()});
ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location.AdvancePC(2).SetEFlag(E).AdvanceIT()});
return false;
}
@ -906,9 +906,8 @@ bool TranslatorVisitor::thumb16_CBZ_CBNZ(bool nonzero, Imm<1> i, Imm<5> imm5, Re
ir.SetCheckBit(ir.IsZero(rn));
const auto [cond_pass, cond_fail] = [this, imm, nonzero] {
const auto skip = IR::Term::LinkBlock{ir.current_location.AdvancePC(2).AdvanceIT()};
const auto branch = IR::Term::LinkBlock{ir.current_location.AdvancePC(imm + 4).AdvanceIT()};
const auto skip = IR::Term::LinkBlockFast{ir.current_location.AdvancePC(2).AdvanceIT()};
const auto branch = IR::Term::LinkBlockFast{ir.current_location.AdvancePC(imm + 4).AdvanceIT()};
if (nonzero) {
return std::make_pair(skip, branch);
} else {
@ -975,10 +974,10 @@ bool TranslatorVisitor::thumb16_B_t1(Cond cond, Imm<8> imm8) {
}
const s32 imm32 = static_cast<s32>((imm8.SignExtend<u32>() << 1) + 4);
const auto then_location = ir.current_location.AdvancePC(imm32).AdvanceIT();
const auto else_location = ir.current_location.AdvancePC(2).AdvanceIT();
const auto then_ = IR::Term::LinkBlockFast{ir.current_location.AdvancePC(imm32).AdvanceIT()};
const auto else_ = IR::Term::LinkBlockFast{ir.current_location.AdvancePC(2).AdvanceIT()};
ir.SetTerm(IR::Term::If{cond, IR::Term::LinkBlock{then_location}, IR::Term::LinkBlock{else_location}});
ir.SetTerm(IR::Term::If{cond, then_, else_});
return false;
}
@ -990,8 +989,12 @@ bool TranslatorVisitor::thumb16_B_t2(Imm<11> imm11) {
const s32 imm32 = static_cast<s32>((imm11.SignExtend<u32>() << 1) + 4);
const auto next_location = ir.current_location.AdvancePC(imm32).AdvanceIT();
ir.SetTerm(IR::Term::LinkBlock{next_location});
// pattern (b +#0)
if (imm32 == 0) {
ir.SetTerm(IR::Term::LinkBlock{next_location});
} else {
ir.SetTerm(IR::Term::LinkBlockFast{next_location});
}
return false;
}

37
src/dynarmic/src/dynarmic/frontend/A32/translate/impl/thumb32_branch.cpp

@ -1,3 +1,6 @@
// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
// SPDX-License-Identifier: GPL-3.0-or-later
/* This file is part of the dynarmic project.
* Copyright (c) 2016 MerryMage
* SPDX-License-Identifier: 0BSD
@ -20,10 +23,8 @@ bool TranslatorVisitor::thumb32_BL_imm(Imm<1> S, Imm<10> hi, Imm<1> j1, Imm<1> j
ir.SetRegister(Reg::LR, ir.Imm32((ir.current_location.PC() + 4) | 1));
const s32 imm32 = static_cast<s32>((concatenate(S, i1, i2, hi, lo).SignExtend<u32>() << 1) + 4);
const auto new_location = ir.current_location
.AdvancePC(imm32)
.AdvanceIT();
ir.SetTerm(IR::Term::LinkBlock{new_location});
auto const new_location = ir.current_location.AdvancePC(imm32).AdvanceIT();
ir.SetTerm(IR::Term::LinkBlockFast{new_location});
return false;
}
@ -44,11 +45,8 @@ bool TranslatorVisitor::thumb32_BLX_imm(Imm<1> S, Imm<10> hi, Imm<1> j1, Imm<1>
ir.SetRegister(Reg::LR, ir.Imm32((ir.current_location.PC() + 4) | 1));
const s32 imm32 = static_cast<s32>(concatenate(S, i1, i2, hi, lo).SignExtend<u32>() << 1);
const auto new_location = ir.current_location
.SetPC(ir.AlignPC(4) + imm32)
.SetTFlag(false)
.AdvanceIT();
ir.SetTerm(IR::Term::LinkBlock{new_location});
const auto new_location = ir.current_location.SetPC(ir.AlignPC(4) + imm32).SetTFlag(false).AdvanceIT();
ir.SetTerm(IR::Term::LinkBlockFast{new_location});
return false;
}
@ -61,10 +59,13 @@ bool TranslatorVisitor::thumb32_B(Imm<1> S, Imm<10> hi, Imm<1> j1, Imm<1> j2, Im
}
const s32 imm32 = static_cast<s32>((concatenate(S, i1, i2, hi, lo).SignExtend<u32>() << 1) + 4);
const auto new_location = ir.current_location
.AdvancePC(imm32)
.AdvanceIT();
ir.SetTerm(IR::Term::LinkBlock{new_location});
auto const new_location = ir.current_location.AdvancePC(imm32).AdvanceIT();
// Pattern to halt execution (b +#0)
if (imm32 == 0) {
ir.SetTerm(IR::Term::LinkBlock{new_location});
} else {
ir.SetTerm(IR::Term::LinkBlockFast{new_location});
}
return false;
}
@ -75,13 +76,9 @@ bool TranslatorVisitor::thumb32_B_cond(Imm<1> S, Cond cond, Imm<6> hi, Imm<1> i1
// Note: i1 and i2 were not inverted from encoding and are opposite compared to the other B instructions.
const s32 imm32 = static_cast<s32>((concatenate(S, i2, i1, hi, lo).SignExtend<u32>() << 1) + 4);
const auto then_location = ir.current_location
.AdvancePC(imm32)
.AdvanceIT();
const auto else_location = ir.current_location
.AdvancePC(4)
.AdvanceIT();
ir.SetTerm(IR::Term::If{cond, IR::Term::LinkBlock{then_location}, IR::Term::LinkBlock{else_location}});
const auto then_ = IR::Term::LinkBlockFast{ir.current_location.AdvancePC(imm32).AdvanceIT()};
const auto else_ = IR::Term::LinkBlockFast{ir.current_location.AdvancePC(4).AdvanceIT()};
ir.SetTerm(IR::Term::If{cond, then_, else_});
return false;
}

24
src/dynarmic/src/dynarmic/frontend/A64/translate/impl/a64_branch.cpp

@ -14,8 +14,8 @@ bool TranslatorVisitor::B_cond(Imm<19> imm19, Cond cond) {
const s64 offset = concatenate(imm19, Imm<2>{0}).SignExtend<s64>();
const u64 target = ir.PC() + offset;
const auto cond_pass = IR::Term::LinkBlock{ir.current_location->SetPC(target)};
const auto cond_fail = IR::Term::LinkBlock{ir.current_location->AdvancePC(4)};
const auto cond_pass = IR::Term::LinkBlockFast{ir.current_location->SetPC(target)};
const auto cond_fail = IR::Term::LinkBlockFast{ir.current_location->AdvancePC(4)};
ir.SetTerm(IR::Term::If{cond, cond_pass, cond_fail});
return false;
}
@ -26,9 +26,9 @@ bool TranslatorVisitor::B_uncond(Imm<26> imm26) {
// Pattern to halt execution (B .)
if (target == ir.PC()) {
ir.SetTerm(IR::Term::LinkBlock{ir.current_location->SetPC(target)});
return false;
} else {
ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location->SetPC(target)});
}
ir.SetTerm(IR::Term::LinkBlockFast{ir.current_location->SetPC(target)});
return false;
}
@ -79,8 +79,8 @@ bool TranslatorVisitor::CBZ(bool sf, Imm<19> imm19, Reg Rt) {
ir.SetCheckBit(ir.IsZero(operand1));
const u64 target = ir.PC() + offset;
const auto cond_pass = IR::Term::LinkBlock{ir.current_location->SetPC(target)};
const auto cond_fail = IR::Term::LinkBlock{ir.current_location->AdvancePC(4)};
const auto cond_pass = IR::Term::LinkBlockFast{ir.current_location->SetPC(target)};
const auto cond_fail = IR::Term::LinkBlockFast{ir.current_location->AdvancePC(4)};
ir.SetTerm(IR::Term::CheckBit{cond_pass, cond_fail});
return false;
}
@ -94,8 +94,8 @@ bool TranslatorVisitor::CBNZ(bool sf, Imm<19> imm19, Reg Rt) {
ir.SetCheckBit(ir.IsZero(operand1));
const u64 target = ir.PC() + offset;
const auto cond_pass = IR::Term::LinkBlock{ir.current_location->AdvancePC(4)};
const auto cond_fail = IR::Term::LinkBlock{ir.current_location->SetPC(target)};
const auto cond_pass = IR::Term::LinkBlockFast{ir.current_location->AdvancePC(4)};
const auto cond_fail = IR::Term::LinkBlockFast{ir.current_location->SetPC(target)};
ir.SetTerm(IR::Term::CheckBit{cond_pass, cond_fail});
return false;
}
@ -110,8 +110,8 @@ bool TranslatorVisitor::TBZ(Imm<1> b5, Imm<5> b40, Imm<14> imm14, Reg Rt) {
ir.SetCheckBit(ir.TestBit(operand, ir.Imm8(bit_pos)));
const u64 target = ir.PC() + offset;
const auto cond_1 = IR::Term::LinkBlock{ir.current_location->AdvancePC(4)};
const auto cond_0 = IR::Term::LinkBlock{ir.current_location->SetPC(target)};
const auto cond_1 = IR::Term::LinkBlockFast{ir.current_location->AdvancePC(4)};
const auto cond_0 = IR::Term::LinkBlockFast{ir.current_location->SetPC(target)};
ir.SetTerm(IR::Term::CheckBit{cond_1, cond_0});
return false;
}
@ -126,8 +126,8 @@ bool TranslatorVisitor::TBNZ(Imm<1> b5, Imm<5> b40, Imm<14> imm14, Reg Rt) {
ir.SetCheckBit(ir.TestBit(operand, ir.Imm8(bit_pos)));
const u64 target = ir.PC() + offset;
const auto cond_1 = IR::Term::LinkBlock{ir.current_location->SetPC(target)};
const auto cond_0 = IR::Term::LinkBlock{ir.current_location->AdvancePC(4)};
const auto cond_1 = IR::Term::LinkBlockFast{ir.current_location->SetPC(target)};
const auto cond_0 = IR::Term::LinkBlockFast{ir.current_location->AdvancePC(4)};
ir.SetTerm(IR::Term::CheckBit{cond_1, cond_0});
return false;
}

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