Editing Talk:PS2 Emulation
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| Latest revision | Your text | ||
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--ee-cache-breaks-block | --ee-cache-breaks-block | ||
No matter which value is used, 1 is set. | No matter which value is used, 1 is set. | ||
== Few popular misunderstandings == | |||
*vu-xgkick-delay take integer between 0-31 (confirmed on both emulator and compiler side), and not float (0.5 is invalid, will be truncated to 0 probably). | |||
*Cop2 rounding in PCSX2 is governed by "EE/FPU" rounding setting, not by VU or VU0. | |||
*Cop2 clamping is hardcoded in PCSX2 as far as i know, if no then is likely also governed by EE/FPU setting not VU/VU0. | |||
*xx-no-clamping setting is not really no clamping known from PCSX2. This is a special mode which can be used regardless of other clamp commands. For comparison, PCSX2 have similar mode only for FPU (Full). To fully mimic that mode, we still need fpu-to-double enabled. | |||
== ee-native-function == | == ee-native-function == | ||
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Same goes for "kernel" injections, they are also based on ID + Hash + address. Generally all "injections" should be safe to be enabled by configs. There is really small chance for hash/address(and id) collision. Not to be confused with "native" / "native-patch" ! | Same goes for "kernel" injections, they are also based on ID + Hash + address. Generally all "injections" should be safe to be enabled by configs. There is really small chance for hash/address(and id) collision. Not to be confused with "native" / "native-patch" ! | ||
== Fast Accurate MUL Implementation == | |||
Whilst Accurate MUL is implemented as very resource heavy fully fledged soft float operation, there is theoretically less accurate but very fast "accurate MUL" available. Surprisingly this is not a copy pasted PS3 implementation (no need to reach Olympus from Lop Nor this time). While this implementation is assumed to be less accurate (than soft floats), the result should be the same as with soft floats. r14 and esi are source floats for operation. So, here it comes: | |||
<pre> | |||
mov edx, r14d | |||
mov eax, esi | |||
xor eax, r14d | |||
shr edx, 23 | |||
and eax, 80000000h | |||
and edx, 0FFh | |||
jz mul_end ; mul by denormal | |||
mov ecx, 817h | |||
bextr ecx, esi, ecx ; esi >> 23 & 0xFF | |||
jz mul_end ; mul by denormal | |||
and r14d, 7FFFFFh | |||
and esi, 7FFFFFh | |||
add edx, ecx | |||
or r14d, 800000h | |||
or esi, 800000h | |||
imul rsi, r14 | |||
shr rsi, 23 | |||
vcvtsi2ss xmm0, xmm0, rsi | |||
vaddss xmm0, xmm0, cs:(float)0.5 | |||
vmovd ecx, xmm0 | |||
shr ecx, 23 | |||
lea edx, [rcx+rdx-115h] | |||
cmp edx, 0FFh | |||
jle case1 | |||
mov ecx, 7F800000h | |||
mov esi, 7FFFFFh | |||
jmp case2 | |||
case1: | |||
add ecx, -150 | |||
xor ebx, ebx | |||
shr esi, cl | |||
mov ecx, edx | |||
and esi, 0FF7FFFFFh | |||
shl ecx, 23 | |||
test edx, edx | |||
cmovle esi, ebx | |||
cmovle ecx, ebx | |||
case2: | |||
or esi, eax | |||
or esi, ecx | |||
mov eax, esi | |||
mul_end: | |||
ret | |||
</pre> | |||
= RESEARCH TO DO = | = RESEARCH TO DO = | ||
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