notenergydrinks/eden
1
0
Fork 0
forked from eden-emu/eden
Code Pull requests Activity

[dynarmic] pre-LZCNT count leading zeroes (integer)

Browse source
This commit is contained in:
lizzie 2025-07-27 19:20:11 +01:00
parent edbce61fa9
commit 16583284e0
Signed by untrusted user: Lizzie
GPG key ID: D9E134A23AD395CE
2 changed files with 50 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

20
externals/dynarmic/src/dynarmic/backend/x64/emit_x64_data_processing.cpp vendored
View file

@ -1568,14 +1568,14 @@ void EmitX64::EmitCountLeadingZeros32(EmitContext& ctx, IR::Inst* inst) {
} else {
const Xbyak::Reg32 source = ctx.reg_alloc.UseScratchGpr(args[0]).cvt32();
const Xbyak::Reg32 result = ctx.reg_alloc.ScratchGpr().cvt32();
const Xbyak::Reg32 temp = ctx.reg_alloc.ScratchGpr().cvt32();
// The result of a bsr of zero is undefined, but zf is set after it.
code.bsr(result, source);
code.mov(source, 0xFFFFFFFF);
code.cmovz(result, source);
code.neg(result);
code.add(result, 31);
code.mov(temp, 32);
code.xor_(result, 31);
code.test(source, source);
code.cmove(result, temp);
ctx.reg_alloc.DefineValue(inst, result);
}
}
@ -1592,14 +1592,14 @@ void EmitX64::EmitCountLeadingZeros64(EmitContext& ctx, IR::Inst* inst) {
} else {
const Xbyak::Reg64 source = ctx.reg_alloc.UseScratchGpr(args[0]).cvt64();
const Xbyak::Reg64 result = ctx.reg_alloc.ScratchGpr().cvt64();
const Xbyak::Reg64 temp = ctx.reg_alloc.ScratchGpr().cvt64();
// The result of a bsr of zero is undefined, but zf is set after it.
code.bsr(result, source);
code.mov(source.cvt32(), 0xFFFFFFFF);
code.cmovz(result.cvt32(), source.cvt32());
code.neg(result.cvt32());
code.add(result.cvt32(), 63);
code.mov(temp.cvt32(), 64);
code.xor_(result.cvt32(), 63);
code.test(source, source);
code.cmove(result.cvt32(), temp.cvt32());
ctx.reg_alloc.DefineValue(inst, result);
}
}

40
externals/dynarmic/tests/A64/a64.cpp vendored
View file

@ -2345,3 +2345,43 @@ TEST_CASE("A64: RBIT{16b}", "[a64]") {
REQUIRE(jit.GetVector(2)[0] == 0xcafedead);
REQUIRE(jit.GetVector(2)[1] == 0xbabebeef);
}
TEST_CASE("A64: CLZ{X}", "[a64]") {
A64TestEnv env;
A64::UserConfig conf{};
conf.callbacks = &env;
A64::Jit jit{conf};
env.code_mem.emplace_back(0xdac01060); // clz x0, x3
env.code_mem.emplace_back(0xdac01081); // clz x1, x4
env.code_mem.emplace_back(0xdac010a2); // clz x2, x5
env.code_mem.emplace_back(0x14000000); // b .
jit.SetRegister(3, 0xfffffffffffffff0);
jit.SetRegister(4, 0x0fffffff0ffffff0);
jit.SetRegister(5, 0x07fffffeffeffef0);
jit.SetPC(0); // at _start
env.ticks_left = 4;
jit.Run();
REQUIRE(jit.GetRegister(0) == 0);
REQUIRE(jit.GetRegister(1) == 4);
REQUIRE(jit.GetRegister(2) == 5);
}
TEST_CASE("A64: CLZ{W}", "[a64]") {
A64TestEnv env;
A64::UserConfig conf{};
conf.callbacks = &env;
A64::Jit jit{conf};
env.code_mem.emplace_back(0x5ac01060); // clz w0, w3
env.code_mem.emplace_back(0x5ac01081); // clz w1, w4
env.code_mem.emplace_back(0x5ac010a2); // clz w2, w5
env.code_mem.emplace_back(0x14000000); // b .
jit.SetRegister(3, 0xffff1110);
jit.SetRegister(4, 0x0fff1110);
jit.SetRegister(5, 0x07fffffe);
jit.SetPC(0); // at _start
env.ticks_left = 4;
jit.Run();
REQUIRE(jit.GetRegister(0) == 0);
REQUIRE(jit.GetRegister(1) == 4);
REQUIRE(jit.GetRegister(2) == 5);
}