SPU Precise interpreter: More efficient float exceptions detection #4155
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GCC is clearly optimizing setting the floating point rounding mode as soon as you actually tun on compiler optimization. https://godbolt.org/g/j1f1GH |
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Just a reminder that our appimages are built with Clang 5.0 |
Marthgun
reviewed
Feb 8, 2018
rpcs3/Emu/Cell/SPUInterpreter.cpp
Outdated
| @@ -1899,18 +1899,19 @@ static void DFASM(SPUThread& spu, spu_opcode_t op, DoubleOp operation) | |||
| case DFASM_S: result = a - b; break; | |||
| case DFASM_M: result = a * b; break; | |||
| } | |||
| if (fetestexcept(FE_INVALID)) | |||
| const u32 e = fetestexcept(FE_ALL_EXCEPT); | |||
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a shortcut for exceptions
Nekotekina
reviewed
Feb 8, 2018
rpcs3/Emu/Cell/SPUThread.cpp
Outdated
| @@ -1262,34 +1262,32 @@ bool SPUThread::set_ch_value(u32 ch, u32 value) | |||
| if (code < 64) | |||
| { | |||
| /* ===== sys_spu_thread_send_event (used by spu_printf) ===== */ | |||
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| u32 spup = code & 63; | |||
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@elad335 I don't see where your problem is. The call to fesetround is clearly inlined. The copy of set_rounding is created because that function might be exported. It won't happen if you declare it static which is the case in SPUInterpreter. See https://godbolt.org/g/kyFsfP |
Nekotekina
reviewed
Feb 28, 2018
rpcs3/Emu/Cell/SPUInterpreter.cpp
Outdated
| { | ||
| spu.fpscr.setDoublePrecisionExceptionFlags(i, FPSCR_DINV); | ||
| result = DOUBLE_NAN; | ||
| } | ||
| else | ||
| { | ||
| if (fetestexcept(FE_OVERFLOW)) | ||
| if (e & FE_OVERFLOW) |
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_mm_getcsr is not compatible with these constants.
There are _MM_MASK_OVERFLOW and similar ones.
read once the MXCSR register and use his value to check for all exceptions
elad335
changed the title
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Optimize floating point exception checking :
read once the MXCSR register and use his value to check for all exceptions.
Optimize setting the floating point's rounding mode with constant values ( also the first commit ) ,cause the compiler won't do it on his own ,as tested in godbolt .