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Accurate FI

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RipleyTom 2024-01-24 05:59:17 +01:00 • committed by Elad.Ash
parent 85f4c38b4e
commit a92b8acba7
2 changed files with 43 additions and 48 deletions
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69
rpcs3/Emu/Cell/SPULLVMRecompiler.cpp
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@ -6075,45 +6075,24 @@ public:
{
register_intrinsic("spu_fi", [&](llvm::CallInst* ci)
{
// TODO: adjustment for denormals(for accurate xfloat only?)
const auto a = bitcast<u32[4]>(value<f32[4]>(ci->getOperand(0)));
const auto b = bitcast<u32[4]>(value<f32[4]>(ci->getOperand(1)));
const auto base = (b & 0x007ffc00u) << 9; // Base fraction
const auto ymul = (b & 0x3ff) * (a & 0x7ffff); // Step fraction * Y fraction (fixed point at 2^-32)
const auto bnew = bitcast<s32[4]>((base - ymul) >> 9) + (sext<s32[4]>(ymul <= base) & (1 << 23)); // Subtract and correct invisible fraction bit
return bitcast<f32[4]>((b & 0xff800000u) | (bitcast<u32[4]>(fpcast<f32[4]>(bnew)) & ~0xff800000u)); // Inject old sign and exponent
const auto comparison = (ymul > base); // Should exponent be adjusted?
const auto bnew = (base - ymul) >> (zext<u32[4]>(comparison) ^ 9); // Shift one less bit if exponent is adjusted
const auto base_result = (b & 0xff800000u) | (bnew & ~0xff800000u); // Inject old sign and exponent
const auto adjustment = bitcast<u32[4]>(sext<s32[4]>(comparison)) & (1 << 23); // exponent adjustement for negative bnew
return bitcast<f32[4]>(base_result - adjustment);
});
const auto [a, b] = get_vrs<f32[4]>(op.ra, op.rb);
if (g_cfg.core.spu_xfloat_accuracy == xfloat_accuracy::accurate)
if (g_cfg.core.spu_xfloat_accuracy == xfloat_accuracy::relaxed)
{
const auto r = eval(fi(a, b));
set_vr(op.rt, r);
return;
}
if (g_cfg.core.spu_xfloat_accuracy == xfloat_accuracy::approximate)
{
register_intrinsic("spu_re", [&](llvm::CallInst* ci)
{
const auto a = value<f32[4]>(ci->getOperand(0));
// Gives accuracy penalty, frest result is within one newton-raphson iteration for accuracy
const auto approx_result = fsplat<f32[4]>(0.999875069f) / a;
return approx_result;
});
register_intrinsic("spu_rsqrte", [&](llvm::CallInst* ci)
{
const auto a = value<f32[4]>(ci->getOperand(0));
// Gives accuracy penalty, frsqest result is within one newton-raphson iteration for accuracy
const auto approx_result = fsplat<f32[4]>(0.999763668f) / fsqrt(fabs(a));
return approx_result;
});
}
else
{
// For relaxed use intrinsics, those make the results vary per cpu
// For relaxed, agressively optimize and use intrinsics, those make the results vary per cpu
register_intrinsic("spu_re", [&](llvm::CallInst* ci)
{
const auto a = value<f32[4]>(ci->getOperand(0));
@ -6125,25 +6104,27 @@ public:
const auto a = value<f32[4]>(ci->getOperand(0));
return frsqe(a);
});
if (const auto [ok, mb] = match_expr(b, frest(match<f32[4]>())); ok && mb.eq(a))
{
erase_stores(b);
set_vr(op.rt, spu_re(a));
return;
}
if (const auto [ok, mb] = match_expr(b, frsqest(match<f32[4]>())); ok && mb.eq(a))
{
erase_stores(b);
set_vr(op.rt, spu_rsqrte(a));
return;
}
}
if (const auto [ok, mb] = match_expr(b, frest(match<f32[4]>())); ok && mb.eq(a))
{
erase_stores(b);
set_vr(op.rt, spu_re(a));
return;
}
if (const auto [ok, mb] = match_expr(b, frsqest(match<f32[4]>())); ok && mb.eq(a))
{
erase_stores(b);
set_vr(op.rt, spu_rsqrte(a));
return;
}
// Do not optimize yet for approximate until we have a full accuracy sequence
const auto r = eval(fi(a, b));
if (!m_interp_magn)
spu_log.todo("[%s:0x%05x] Unmatched spu_fi found", m_hash, m_pos);
// if (!m_interp_magn)
// spu_log.todo("[%s:0x%05x] Unmatched spu_fi found", m_hash, m_pos);
set_vr(op.rt, r);
}